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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0705.4398 | Martin Bojowald | Martin Bojowald | The Dark Side of a Patchwork Universe | 24 pages, 2 figures, Contribution to the special issue on Dark Energy
by Gen. Rel. Grav | Gen.Rel.Grav.40:639-660,2008 | 10.1007/s10714-007-0558-4 | IGPG-07/5-5 | gr-qc astro-ph hep-th | null | While observational cosmology has recently progressed fast, it revealed a
serious dilemma called dark energy: an unknown source of exotic energy with
negative pressure driving a current accelerating phase of the universe. All
attempts so far to find a convincing theoretical explanation have failed, so
that one of the last hopes is the yet to be developed quantum theory of
gravity. In this article, loop quantum gravity is considered as a candidate,
with an emphasis on properties which might play a role for the dark energy
problem. Its basic feature is the discrete structure of space, often associated
with quantum theories of gravity on general grounds. This gives rise to
well-defined matter Hamiltonian operators and thus sheds light on conceptual
questions related to the cosmological constant problem. It also implies typical
quantum geometry effects which, from a more phenomenological point of view, may
result in dark energy. In particular the latter scenario allows several
non-trivial tests which can be made more precise by detailed observations in
combination with a quantitative study of numerical quantum gravity. If the
speculative possibility of a loop quantum gravitational origin of dark energy
turns out to be realized, a program as outlined here will help to hammer out
our ideas for a quantum theory of gravity, and at the same time allow
predictions for the distant future of our universe.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:30:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bojowald",
"Martin",
""
]
] |
0705.4399 | M. S. Nanda Kumar | M. S. N. Kumar and J. M. C. Grave | Spitzer-IRAC GLIMPSE of high mass protostellar objects. I Infrared point
sources and nebulae | 13 pages, 7 figures, accepted by A&A | Astron.Astrophys.472:155-161,2007 | 10.1051/0004-6361:20077103 | null | astro-ph | null | The GLIMPSE archive was used to obtain 3.6--8.0micron, point source
photometry and images for 381 massive protostellar candidates lying in the
Galactic mid-plane. The colours, magnitudes and spectral indicies of sources in
each of the 381 target fields were analysed and compared with the predictions
of 2D radiative transfer model simulations. Although no discernable embedded
clusters were found in any targets, multiple sources or associations of
redenned young stellar objects were found in many sources indicating
multiplicity at birth. The spectral index ($\alpha$) of these point sources in
3.6--8.0mum bands display large values of $\alpha$=2--5. A color-magnitude
analog plot was used to identify 79 infrared counterparts to the HMPOs. Compact
nebulae are found in 75% of the detected sources with morphologies that can be
well described by core-halo, cometary, shell-like and bipolar geometries
similar to those observed in ultra-compact HII regions. The IRAC band SEDs of
the IR counterparts of HMPOs are best described to represent YSOs with a mass
range of 8--20\msun in their Class I stages when compared with 2D radiative
transfer models. They also suggest that the high $\alpha$ values represent
reprocessed star/star+disk emission that is arising in the dense envelopes.
Thus we are witnessing the luminous envelopes around the protostars rather than
their photospheres or disks. We argue that the compact infrared nebulae likely
reflect the underlying physical structure of the dense cores and are found to
imitate the morphologies of known UCHII regions. Our results favour models of
continuuing accretion involving both molecular and ionised accretion components
to build the most massive stars rather than purely molecular rapid accretion
flows.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:27:09 GMT"
}
] | 2009-05-11T00:00:00 | [
[
"Kumar",
"M. S. N.",
""
],
[
"Grave",
"J. M. C.",
""
]
] |
0705.4400 | Denis Terwagne | D. Terwagne, S. Dorbolo and N. Vandewalle | About the lifetime of a bouncing droplet | (5 pages, 7 figures) | null | 10.1103/PhysRevE.76.056311 | null | nlin.CD | null | When a droplet is gently laid onto the surface of the same liquid, it stays
at rest for a moment before coalescence. The coalescence can be delayed and
sometimes inhibited by injecting fresh air under the droplet. This can happen
when the surface of the bath oscillates vertically, in this case the droplet
basically bounces on the interface. The lifetime of the droplet has been
studied with respect to the amplitude and the frequency of the excitation. The
lifetime decreases when the acceleration increases. The thickness of the air
film between the droplet and the bath has been investigated using interference
fringes obtained when the system is illuminated by low pressure sodium lamps.
Moreover, both the shape evolution and the motion of the droplet center of mass
have been recorded in order to evidence the phase offset between the
deformation and the trajectory. A short lifetime is correlated to a small air
film thickness and to a large phase offset between the maximum of deformation
and the minimum of the vertical position of the centre of mass.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:27:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Terwagne",
"D.",
""
],
[
"Dorbolo",
"S.",
""
],
[
"Vandewalle",
"N.",
""
]
] |
0705.4401 | Li-Xin Li | Li-Xin Li | Are Gamma-Ray Bursts Standard Candles? | 4 pages, including 4 figures. To appear in the proceedings of
"070228: The Next Decade of GRB afterglows", Amsterdam, 19-23 March 2007 | null | null | null | astro-ph | null | By dividing a sample of 48 long-duration gamma-ray bursts (GRBs) into four
groups with redshift from low to high and fitting each group with the Amati
relation log Eiso = a + b log Epeak, I find that parameters a and b vary with
the mean redshift of the GRBs in each group systematically and significantly.
The results suggest that GRBs evolve strongly with the cosmic redshift and
hence are not standard candles.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:28:07 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Li",
"Li-Xin",
""
]
] |
0705.4402 | Reinhard Alkofer | R. Alkofer, C.S. Fischer, F. Llanes-Estrada, K. Schwenzer | What the Infrared Behaviour of QCD Vertex Functions in Landau gauge can
tell us about Confinement | 13 pages, 13 figures; to appear in the Proceedings of ``X Hadron
Physics 2007'', Florianopolis, Brazil, March 26 - 31, 2007 | Int.J.Mod.Phys.E16:2720-2732,2007 | 10.1142/S0218301307008367 | null | hep-ph | null | The infrared behaviour of Landau gauge QCD vertex functions is investigated
employing a skeleton expansion of the Dyson-Schwinger and Renormalization Group
equations. Results for the ghost-gluon, three-gluon, four-gluon and quark-gluon
vertex functions are presented. Positivity violation of the gluon propagator,
and thus gluon confinement, is demonstrated. Results of the Dyson-Schwinger
equations for a finite volume are compared to corresponding lattice data. It is
analytically demonstrated that a linear rising potential between heavy quarks
can be generated by infrared singularities in the dressed quark-gluon vertex.
The selfconsistent mechanism that generates these singularities necessarily
entails the scalar Dirac amplitudes of the full vertex and the quark
propagator. These can only be present when chiral symmetry is broken, either
explicitly or dynamically.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:29:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Alkofer",
"R.",
""
],
[
"Fischer",
"C. S.",
""
],
[
"Llanes-Estrada",
"F.",
""
],
[
"Schwenzer",
"K.",
""
]
] |
0705.4403 | Anthony Minter | Anthony H. Minter, Fernando Camilo, Scott M. Ransom, Jules P. Halpern,
and Neil Zimmerman | Neutral Hydrogen Absorption Toward XTE J1810-197: the Distance to a
Radio-Emitting Magnetar | 35 pages, 11 figures, 5 Tables Submitted to ApJ | null | 10.1086/529005 | null | astro-ph | null | We have used the Green Bank Telescope to measure HI absorption against the
anomalous X-ray pulsar XTE J1810-197. Assuming a flat rotation curve, we find
that XTE J1810-197 is located at a distance of 3.4(+0.5,-0.7) kpc. For a
rotation curve that incorporates a model of the Galactic bar, we obtain a
distance of 4.0(+0.3,-0.8) kpc. Using a rotation curve that incorporates a
model of the Galactic bar and the spiral arms of the Galaxy, the distance is
3.7(+/-0.6) kpc. These values are consistent with the distance to XTE J1810-197
of about 3.3 kpc derived from its dispersion measure, and estimates of 2-5 kpc
obtained from fits to its X-ray spectra. Overall, we determine that XTE
J1810-197 is located at a distance of 3.5(+/-0.5) kpc, possibly not far in
front of the infrared dark cloud G10.74-0.13. We also used the GBT in an
attempt to measure absorption in the OH 1612, 1665, 1667, and 1720 MHz lines
against XTE J1810-197. We were unsuccessful in this, mainly because of its
declining radio flux density. Analysis of HI 21 cm, OH, and CO(2-1) emission
toward XTE J1810-197 allows us to place a lower limit of $N_{\rm H} \ga 4.6
\times 10^{21}$ cm$^{-2}$ on the non-ionized hydrogen column density to
\magnetar, consistent with estimates obtained from fits to its X-ray spectra.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:32:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Minter",
"Anthony H.",
""
],
[
"Camilo",
"Fernando",
""
],
[
"Ransom",
"Scott M.",
""
],
[
"Halpern",
"Jules P.",
""
],
[
"Zimmerman",
"Neil",
""
]
] |
0705.4404 | Clarisse Tur | Clarisse Tur, Alexander Heger, Sam M. Austin | On the Sensitivity of Massive Star Nucleosynthesis and Evolution to
Solar Abundances and to Uncertainties in Helium Burning Reaction Rates | Accepted for publication by the Astrophysical Journal | null | 10.1086/523095 | LAUR 07-4279 | astro-ph | null | We explore the dependence of pre-supernova evolution and supernova
nucleosynthesis yields on the uncertainties in helium burning reaction rates.
Using the revised solar abundances of Lodders (2003) for the initial stellar
composition, instead of those of Anders & Grevesse (1989), changes the
supernova yields and limits the constraints that those yields place on the
12C(a,g)16O reaction rate. The production factors of medium-weight elements (A
= 16-40) were found to be in reasonable agreement with observed solar ratios
within the current experimental uncertainties in the triple alpha reaction
rate. Simultaneous variations by the same amount in both reaction rates or in
either of them separately, however, can induce significant changes in the
central 12C abundance at core carbon ignition and in the mass of the supernova
remnant. It therefore remains important to have experimental determinations of
the helium burning rates so that their ratio and absolute values are known with
an accuracy of 10% or better.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:39:17 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Jun 2007 14:37:15 GMT"
},
{
"version": "v3",
"created": "Wed, 8 Aug 2007 17:48:59 GMT"
},
{
"version": "v4",
"created": "Mon, 10 Sep 2007 21:07:22 GMT"
},
{
"version": "v5",
"created": "Sun, 9 Dec 2007 17:36:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tur",
"Clarisse",
""
],
[
"Heger",
"Alexander",
""
],
[
"Austin",
"Sam M.",
""
]
] |
0705.4405 | Pierre-Henri Chavanis | Pierre-Henri Chavanis | Hamiltonian and Brownian systems with long-range interactions: III. The
BBGKY hierarchy for spatially inhomogeneous systems | null | Physica A, 387, 787 (2008) | 10.1016/j.physa.2007.10.026 | null | cond-mat.stat-mech | null | We study the growth of correlations in systems with weak long-range
interactions. Starting from the BBGKY hierarchy, we determine the evolution of
the two-body correlation function by using an expansion of the solutions of the
hierarchy in powers of 1/N in a proper thermodynamic limit $N\to +\infty$.
These correlations are responsible for the ``collisional'' evolution of the
system beyond the Vlasov regime due to finite $N$ effects. We obtain a general
kinetic equation that can be applied to spatially inhomogeneous systems and
that takes into account memory effects. These peculiarities are specific to
systems with unshielded long-range interactions. For spatially homogeneous
systems with short memory time like plasmas, we recover the classical Landau
(or Lenard-Balescu) equations. An interest of our approach is to develop a
formalism that remains in physical space (instead of Fourier space) and that
can deal with spatially inhomogeneous systems. This enlightens the basic
physics and provides novel kinetic equations with a clear physical
interpretation. However, unless we restrict ourselves to spatially homogeneous
systems, closed kinetic equations can be obtained only if we ignore some
collective effects between particles. General exact coupled equations taking
into account collective effects are also given. We use this kinetic theory to
discuss the processes of violent collisionless relaxation and slow collisional
relaxation in systems with weak long-range interactions. In particular, we
investigate the dependence of the relaxation time with the system size and
provide a coherent discussion of all the numerical results obtained for these
systems.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:42:53 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 12:43:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chavanis",
"Pierre-Henri",
""
]
] |
0705.4406 | Anders Kock | Anders Kock | Infinitesimal cubical structure, and higher connections | 31 pages | null | null | null | math.CT | null | In the context of Synthetic Differential Geometry, we describe a notion of
higher connection with values in a cubical groupoid. We do this by exploiting a
certain structure of cubical complex derived from the first neighbourhood of
the diagonal of a manifold. This cubical complex consists of infinitesimal
parallelelpipeda.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 14:43:17 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Kock",
"Anders",
""
]
] |
0705.4407 | Christian Fischer | Christian S. Fischer, Dominik Nickel and Jochen Wambach | Hadronic unquenching effects in the quark propagator | 27 pages, 15 figures, minor corrections and clarifications; version
to appear in PRD | Phys.Rev.D76:094009,2007 | 10.1103/PhysRevD.76.094009 | null | hep-ph hep-lat nucl-th | null | We investigate hadronic unquenching effects in light quarks and mesons.
Within the non-perturbative continuum framework of Schwinger-Dyson and
Bethe-Salpeter equations we quantify the strength of the back reaction of the
pion onto the quark-gluon interaction. To this end we add a Yang-Mills part of
the interaction such that unquenched lattice results for various current quark
masses are reproduced. We find considerable effects in the quark mass function
at low momenta as well as for the chiral condensate. The quark wave function is
less affected. The Gell--Mann-Oakes-Renner relation is valid to good accuracy
up to pion masses of 400-500 MeV. As a byproduct of our investigation we verify
the Coleman theorem, that chiral symmetry cannot be broken spontaneously when
QCD is reduced to 1+1 dimensions.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:05:55 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Nov 2007 10:06:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fischer",
"Christian S.",
""
],
[
"Nickel",
"Dominik",
""
],
[
"Wambach",
"Jochen",
""
]
] |
0705.4408 | Paolo Massarotti | F. Ambrosino, A. Antonelli, M. Antonelli, F. Archilli, C. Bacci, P.
Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C. Bloise, S. Bocchetta, V.
Bocci, F. Bossi, P. Branchini, R. Caloi, P. Campana, G. Capon, T. Capussela,
F. Ceradini, S. Chi, G. Chiefari, P. Ciambrone, E. De Lucia, A. De Santis, P.
De Simone, G. De Zorzi, A. Denig, A. Di Domenico, C. Di Donato, S. Di Falco,
B. Di Micco, A. Doria, M. Dreucci, G. Felici, A. Ferrari, M. L. Ferrer, G.
Finocchiaro, S. Fiore, C. Forti, P. Franzini, C. Gatti, P. Gauzzi, S.
Giovannella, E. Gorini, E. Graziani, M. Incagli, W. Kluge, V. Kulikov, F.
Lacava, G. Lanfranchi, J. Lee-Franzini, D. Leone, M. Martini, P. Massarotti,
W. Mei, S. Meola, S. Miscetti, M. Moulson, S. M\"uller, F. Murtas, M.
Napolitano, F. Nguyen, M. Palutan, E. Pasqualucci, A. Passeri, V. Patera, F.
Perfetto, M. Primavera, P. Santangelo, G. Saracino, B. Sciascia, A. Sciubba,
F. Scuri, I. Sfiligoi, T. Spadaro, M. Testa, L. Tortora, P. Valente, B.
Valeriani, G. Venanzoni, R. Versaci, G. Xu (KLOE collaboration, presented by
Paolo Massarotti) | Charged kaon lifetime at KLOE | 3 pages, 3 figures, to appear in the proceedings of 42nd Rencontres
de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta
Valley, Italy, 10-17 Mar 2007 | null | null | null | hep-ex | null | Preliminary result on the charged kaon lifetime, obtained by the KLOE
experiment operating at DA$\Phi$NE, the Frascati $\phi$-factory, is presented
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:04:55 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Jun 2007 13:18:05 GMT"
},
{
"version": "v3",
"created": "Mon, 16 Jul 2007 10:24:54 GMT"
}
] | 2019-08-12T00:00:00 | [
[
"Ambrosino",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Antonelli",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Antonelli",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Archilli",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bacci",
"C.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Beltrame",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bencivenni",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bertolucci",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bini",
"C.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bloise",
"C.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bocchetta",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bocci",
"V.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Bossi",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Branchini",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Caloi",
"R.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Campana",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Capon",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Capussela",
"T.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Ceradini",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Chi",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Chiefari",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Ciambrone",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"De Lucia",
"E.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"De Santis",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"De Simone",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"De Zorzi",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Denig",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Di Domenico",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Di Donato",
"C.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Di Falco",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Di Micco",
"B.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Doria",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Dreucci",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Felici",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Ferrari",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Ferrer",
"M. L.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Finocchiaro",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Fiore",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Forti",
"C.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Franzini",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Gatti",
"C.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Gauzzi",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Giovannella",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Gorini",
"E.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Graziani",
"E.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Incagli",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Kluge",
"W.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Kulikov",
"V.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Lacava",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Lanfranchi",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Lee-Franzini",
"J.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Leone",
"D.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Martini",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Massarotti",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Mei",
"W.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Meola",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Miscetti",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Moulson",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Müller",
"S.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Murtas",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Napolitano",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Nguyen",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Palutan",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Pasqualucci",
"E.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Passeri",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Patera",
"V.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Perfetto",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Primavera",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Santangelo",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Saracino",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Sciascia",
"B.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Sciubba",
"A.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Scuri",
"F.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Sfiligoi",
"I.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Spadaro",
"T.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Testa",
"M.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Tortora",
"L.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Valente",
"P.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Valeriani",
"B.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Venanzoni",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Versaci",
"R.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
],
[
"Xu",
"G.",
"",
"KLOE collaboration, presented by\n Paolo Massarotti"
]
] |
0705.4409 | Hongbao Zhang | Hongbao Zhang, Wuhan Zhong, Zong-Hong Zhu, and Song He | Exploring holographic dark energy model with Sandage-Loeb test | Typos corrected, version to appear in PRD | Phys.Rev.D76:123508,2007 | 10.1103/PhysRevD.76.123508 | null | astro-ph | null | Taking into account that Sandage-Loeb test is unique in its coverage of the
redshift desert and available in the near future, we explore the cosmic time
evolution behavior of the source redshift for holographic dark energy model, an
important competing cosmological model. As a result, we find that Sandage-Loeb
test can provide a extremely strong bound on $\Omega^0_m$, while its constraint
on another dimensionless parameter $\lambda$ is weak. In addition, it is
proposed here for the first time that we can also constrain various
cosmological model by measuring the value of $z_{max}$ at which the peak of
redshift velocity occurs. Combining this new proposed method with the
traditional Sandage-Loeb test, we should be able to provide a better constraint
on $\lambda$, at least from the theoretical perspective.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:32:55 GMT"
},
{
"version": "v2",
"created": "Thu, 31 May 2007 04:31:54 GMT"
},
{
"version": "v3",
"created": "Wed, 14 Nov 2007 01:12:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Zhang",
"Hongbao",
""
],
[
"Zhong",
"Wuhan",
""
],
[
"Zhu",
"Zong-Hong",
""
],
[
"He",
"Song",
""
]
] |
0705.4410 | Tijl Verhoelst | T. Verhoelst, E. van Aarle, B. Acke | Direct diameter measurement of a star filling its Roche Lobe: The
semi-detached binary SS Leporis spatially resolved with VINCI/VLTI | 4 pages, 2 figures, accepted for publication in A&A Letters on
26/05/2007 | null | 10.1051/0004-6361:20077840 | null | astro-ph | null | Stellar evolution in close binary systems is strongly influenced by mass
transfer from one star to the other when one component fills its zero-velocity
surface or Roche Lobe. SS Lep is a fairly nearby close binary showing the Algol
paradox and a shell spectrum, both indicative of (past) mass transfer. To study
the process of mass transfer and its evolutionary consequences, we aim at a
direct characterisation of the spatial dimensions of the different components
of SS Lep with IR interferometry. We use VINCI/VLTI interferometric
observations in the K band and photometric observations from the UV to the
far-IR. The visibilities are interpreted with simple geometrical models and the
Spectral Energy Distribution (SED) is decomposed into the three main
components: A star, M star and dust shell/disk. From the SED, we find that the
main emitters in the K band are the M star and the circumstellar environment.
Both are spatially resolved with the VINCI observations, showing the excess to
be circumbinary and showing the M star to have a size equal to its Roche Lobe.
We conclude that we have, for the first time, directly resolved a star filling
its Roche Lobe. The resulting mass transfer is probably the cause of (1) the
circumbinary dust disk of which we see the hot inner region spatially resolved
in our observations, (2) the unusually high luminosity of the A star and (3)
the shell spectrum seen in the UV and optical spectra.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:13:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Verhoelst",
"T.",
""
],
[
"van Aarle",
"E.",
""
],
[
"Acke",
"B.",
""
]
] |
0705.4411 | Dr. Anirudh Pradhan | Anirudh Pradhan, P. K. Singh and A. K. Yadav | A Plane-Symmetric Inhomogeneous Cosmological Model of Perfect Fluid
Distribution with Electromagnetic Field I | 11 pages, no figure | Commun.Theor.Phys.54:191-196,2010 | 10.1088/0253-6102/54/1/35 | null | gr-qc | null | A plane-symmetric inhomogeneous cosmological model of perfect fluid
distribution with electro-magnetic field is obtained. The source of the
magnetic field is due to an electric current produced along the z-axis.
$F_{12}$ is the non-vanishing component of electromagnetic field tensor. To get
a deterministic solution, we assume the free gravitational field is Petrov
type-II non-degenerate. The behaviour of the electro-magnetic field tensor
together with some physical aspects of the model are also discussed.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:15:22 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2007 14:08:24 GMT"
}
] | 2010-09-27T00:00:00 | [
[
"Pradhan",
"Anirudh",
""
],
[
"Singh",
"P. K.",
""
],
[
"Yadav",
"A. K.",
""
]
] |
0705.4412 | Yohan Payan | Pierre Mozer (TIMC - IMAG), Pierre Conort, Antoine Leroy (TIMC -
IMAG), Michael Baumann (TIMC - IMAG), Yohan Payan (TIMC - IMAG), Jocelyne
Troccaz (TIMC - IMAG), Emmanuel Chartier-Kastler, Fran\c{c}ois Richard | Aid to Percutaneous Renal Access by Virtual Projection of the Ultrasound
Puncture Tract onto Fluoroscopic Images | null | Journal of Endourology 21, 5 (2007) 460-5 | 10.1089/end.2006.0168 | null | physics.med-ph | null | Background and Purpose: Percutaneous renal access in the context of
percutaneous nephrolithotomy (PCNL) is a difficult technique, requiring rapid
and precise access to a particular calix. We present a computerized system
designed to improve percutaneous renal access by projecting the ultrasound
puncture tract onto fluoroscopic images. Materials and Methods: The system
consists of a computer and a localizer allowing spatial localization of the
position of the various instruments. Without any human intervention, the
ultrasound nephrostomy tract is superimposed in real time onto fluoroscopic
images acquired in various views. Results: We tested our approach by laboratory
experiments on a phantom. Also, after approval by our institution's Ethics
Committee, we validated this technique in the operating room during PCNL in one
patient. Conclusion: Our system is reliable, and the absence of
image-processing procedures makes it robust. We have initiated a prospective
study to validate this technique both for PCNL specialists and as a learning
tool.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:26:56 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Mozer",
"Pierre",
"",
"TIMC - IMAG"
],
[
"Conort",
"Pierre",
"",
"TIMC -\n IMAG"
],
[
"Leroy",
"Antoine",
"",
"TIMC -\n IMAG"
],
[
"Baumann",
"Michael",
"",
"TIMC - IMAG"
],
[
"Payan",
"Yohan",
"",
"TIMC - IMAG"
],
[
"Troccaz",
"Jocelyne",
"",
"TIMC - IMAG"
],
[
"Chartier-Kastler",
"Emmanuel",
""
],
[
"Richard",
"François",
""
]
] |
0705.4413 | Evgeny Plekhanov | E. Plekhanov, A. Avella, and F. Mancini | Entanglement in the 1D extended anisotropic Heisenberg model | 2 pages, 3 figures, presented at SCES'07 Houston, May 2007 | Physica B 403, 1282 (2008) | 10.1016/j.physb.2007.10.127 | null | cond-mat.mes-hall cond-mat.str-el quant-ph | null | We present a study of entanglement in the case of the 1D extended anisotropic
Heisenberg model. We investigate two quantum phase transitions (QPTs) within
the previously found ergodicity phase diagram [E. Plekhanov, A. Avella, and F.
Mancini Phys. Rev. B \textbf{74}, 115120 (2006)]. Our calculations are done by
means of the numerically exact Lanczos method at T=0, followed by a finite-size
scaling. As a measure of entanglement we use the concurrence for two spins out
of the system. We conclude from our studies that these QPTs are accompanied by
a qualitative entanglement change.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:27:17 GMT"
}
] | 2018-04-09T00:00:00 | [
[
"Plekhanov",
"E.",
""
],
[
"Avella",
"A.",
""
],
[
"Mancini",
"F.",
""
]
] |
0705.4414 | Antonio Bassetto | A. Bassetto and G. De Pol | SYM N=4 in light-cone gauge and the "bridge" identities | 12 pages, LaTeX, uses cernrep, axodraw, cancel; figures included;
minor improvements, references added, version accepted for publication in
Phys. Rev. D | Phys.Rev.D77:045001,2008 | 10.1103/PhysRevD.77.045001 | DFPD/TH 07-07 | hep-th | null | The light-cone gauge allows to single out a set of ``transverse'' fields
(TF), whose Green functions are free from UV divergences in SYM N=4. Green
functions with external lines involving the remaining fields do instead exhibit
divergences: indeed those fields can be expressed, by solving their equations
of motion, as composite operators in terms of ``transverse'' fields. A set of
exact identities (bridge identities) automatically realize their insertions in
a path-integral formulation.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:30:36 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Dec 2007 11:30:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bassetto",
"A.",
""
],
[
"De Pol",
"G.",
""
]
] |
0705.4415 | Cnrs : Umr 6057 Laboratoire Parole Et Langage | Carine Andr\'e (LPL), Alain Ghio (LPL), Christian Cav\'e (LPL),
Bernard Teston (LPL) | PERCEVAL: a Computer-Driven System for Experimentation on Auditory and
Visual Perception | null | Proceedings of International Congress of Phonetic Sciences (ICPhS)
(2003) 1421-1424 | null | 1557 | cs.SE | null | Since perception tests are highly time-consuming, there is a need to automate
as many operations as possible, such as stimulus generation, procedure control,
perception testing, and data analysis. The computer-driven system we are
presenting here meets these objectives. To achieve large flexibility, the tests
are controlled by scripts. The system's core software resembles that of a
lexical-syntactic analyzer, which reads and interprets script files sent to it.
The execution sequence (trial) is modified in accordance with the commands and
data received. This type of operation provides a great deal of flexibility and
supports a wide variety of tests such as auditory-lexical decision making,
phoneme monitoring, gating, phonetic categorization, word identification, voice
quality, etc. To achieve good performance, we were careful about timing
accuracy, which is the greatest problem in computerized perception tests.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:31:07 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"André",
"Carine",
"",
"LPL"
],
[
"Ghio",
"Alain",
"",
"LPL"
],
[
"Cavé",
"Christian",
"",
"LPL"
],
[
"Teston",
"Bernard",
"",
"LPL"
]
] |
0705.4416 | Zhihui Wang | Caterina Guiot, Nicola Pugno, Pier Paolo Delsanto, Thomas S. Deisboeck | Physical Aspects of Cancer Invasion | 20 pages, 2 figures | null | 10.1088/1478-3975/4/4/P01 | null | physics.bio-ph | null | Invasiveness, one of the hallmarks of tumor progression, represents the
tumor's ability to expand into the host tissue by means of several complex
biochemical and biomechanical processes. Since certain aspects of the problem
present a striking resemblance with well known physical mechanisms, such as the
mechanical insertion of a solid inclusion in an elastic material specimen [1,
2] or a water drop impinging on a surface [3], we propose here an analogy
between these physical processes and a cancer system's invasive branching into
the surrounding tissue. Accounting for its solid and viscous properties, we
present a unifying concept that the tumor behaves as a granular solid. While
our model has been explicitly formulated for multicellular tumor spheroids in
vitro, it should also contribute to a better understanding of tumor invasion in
vivo.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:35:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Guiot",
"Caterina",
""
],
[
"Pugno",
"Nicola",
""
],
[
"Delsanto",
"Pier Paolo",
""
],
[
"Deisboeck",
"Thomas S.",
""
]
] |
0705.4417 | Alexander V. Milovanov Dr. | Alexander V. Milovanov (Department of Physics and Technology,
University of Tromso, Tromso, Norway), Jens Juul Rasmussen (Optics and Plasma
Research Department, Riso National Laboratory, Technical University of
Denmark, Roskilde, Denmark), Kristoffer Rypdal (Department of Physics and
Technology, University of Tromso, Tromso, Norway) | Stretched exponential relaxation and ac universality in disordered
dielectrics | 8 pages, 2 figures | null | 10.1103/PhysRevB.76.104201 | null | cond-mat.dis-nn cond-mat.stat-mech | null | This paper is concerned with the connection between the properties of
dielectric relaxation and ac (alternating-current) conduction in disordered
dielectrics. The discussion is divided between the classical linear-response
theory and a self-consistent dynamical modeling. The key issues are, stretched
exponential character of dielectric relaxation, power-law power spectral
density, and anomalous dependence of ac conduction coefficient on frequency. We
propose a self-consistent model of dielectric relaxation, in which the
relaxations are described by a stretched exponential decay function.
Mathematically, our study refers to the expanding area of fractional calculus
and we propose a systematic derivation of the fractional relaxation and
fractional diffusion equations from the property of ac universality.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:43:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Milovanov",
"Alexander V.",
"",
"Department of Physics and Technology,\n University of Tromso, Tromso, Norway"
],
[
"Rasmussen",
"Jens Juul",
"",
"Optics and Plasma\n Research Department, Riso National Laboratory, Technical University of\n Denmark, Roskilde, Denmark"
],
[
"Rypdal",
"Kristoffer",
"",
"Department of Physics and\n Technology, University of Tromso, Tromso, Norway"
]
] |
0705.4418 | Giuseppe Pagliara | A. Drago, G. Pagliara, J. Schaffner-Bielich | Formation of Quark Phases in compact stars and their connection to
Gamma-Ray-Bursts | 6 pages, 3 figures, to appear in the proceedings of 3th International
Conference on Nuclear Physics in Astrophysics (NPAIII), 26 - 31 March 2007
Dresden, Germany | J.Phys.G35:014052,2008 | 10.1088/0954-3899/35/1/014052 | null | astro-ph | null | We analyse the occurrence of quiescent times in the temporal structure of the
Gamma-Ray-Bursts (GRBs) light curves. We show that if a long quiescent time is
present, it is possible to divide the total duration of GRBs into three
periods: the pre-quiescence emission, the quiescent time and the
post-quiescence emission. We then discuss a model of the GRBs inner engine
based on the formation of quark phases during the life of an hadronic star.
Within this model the pre-quiescence emission is interpreted as due to the
deconfinement of quark inside an hadronic star and the formation of 2SC quark
matter. The post-quiescence emission is due to the conversion of 2SC into the
Color-Flavor-Locking (CFL) phase. The temporal delay between these two
processes is connected with the nucleation time of the CFL phase in the 2SC
phase and it can be associated with the observed quiescent times in the GRBs
light curves. The stability of CFL cores in compact stars is also discussed.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:36:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Drago",
"A.",
""
],
[
"Pagliara",
"G.",
""
],
[
"Schaffner-Bielich",
"J.",
""
]
] |
0705.4419 | Zurab Tavartkiladze | K.S. Babu, Abdel G. Bachri, Zurab Tavartkiladze | Predictive Model of Inverted Neutrino Mass Hierarchy and Resonant
Leptogenesis | Model slightly improved, references added, version will appear in
IJMP | Int.J.Mod.Phys.A23:1679-1696,2008 | 10.1142/S0217751X08039761 | OSU-HEP-07-01 | hep-ph | null | We present a new realization of inverted neutrino mass hierarchy based on
$S_3 \times {\cal U}(1)$ flavor symmetry. In this scenario, the deviation of
the solar oscillation angle from $\pi/4$ is correlated with the value of
$\theta_{13}$, as they are both induced by a common mixing angle in the charged
lepton sector. We find several interesting predictions: $\te_{13}\geq 0.13$,
$\sin^2\te_{12}\geq 0.31$, $\sin^2\te_{23}\simeq 0.5$ and $0\leq \cos \de \leq
0.7$ for the neutrino oscillation parameters and $0.01 {\rm
eV}\stackrel{<}{_\sim}m_{\bt \bt}\stackrel{<}{_\sim} 0.02 {\rm eV}$ for the
effective neutrino mass in neutrino-less double $\bt $-decay. We show that our
scenario can also explain naturally the observed baryon asymmetry of the
universe via resonant leptogenesis. The masses of the decaying right--handed
neutrinos can be in the range $(10^3 - 10^7)$ GeV, which would avoid the
generic gravitino problem of supersymmetric models.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:40:59 GMT"
},
{
"version": "v2",
"created": "Sat, 11 Aug 2007 00:15:44 GMT"
},
{
"version": "v3",
"created": "Mon, 3 Mar 2008 19:17:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Babu",
"K. S.",
""
],
[
"Bachri",
"Abdel G.",
""
],
[
"Tavartkiladze",
"Zurab",
""
]
] |
0705.4420 | Savino Longo | P.Diomede, S.Longo and M.Capitelli | Non equilibrium velocity distributions of H- ions in H2 plasmas and
photodetachment measurements | 17 pages, 8 figures | null | null | null | physics.plasm-ph | null | A theoretical study of the energy distribution function of the negative
hydrogen ion H- in typical conditions for multicusp ion sources is presented.
The case of H/H2 mixture is studied by a Monte Carlo solution of the kinetic
equation for H- transport. A simple analytical model is obtained for the case
of a fully dissociated H plasma and uniform reduced electric field (E/N).
Results are in good agreement with the two-group distribution deduced from
laser photodetachment experiments and explain the low energy group as an effect
of the charge exchange collisions of negative ions with H atoms.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 15:55:21 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Diomede",
"P.",
""
],
[
"Longo",
"S.",
""
],
[
"Capitelli",
"M.",
""
]
] |
0705.4421 | Robert Fleischer | Robert Fleischer (CERN) | Exploring CP Violation and Penguin Effects through $B^0_d \to D^+ D^-$
and $B^0_s \to D^+_s D^-_s$ | 18 pages, 6 figures | Eur.Phys.J.C51:849-858,2007 | 10.1140/epjc/s10052-007-0341-4 | CERN-PH-TH/2007-092 | hep-ph | null | The decay $B^0_d \to D^+ D^-$ offers an interesting probe of CP violation,
but requires control of penguin effects, which can be done through $B^0_s \to
D^+_s D^-_s$ by means of the $U$-spin flavour symmetry of strong interactions.
Recently, the Belle collaboration reported indications of large CP violation in
the $B^0_d$ decay, which were, however, not confirmed by BaBar, and first
signals of the $B^0_s$ channel were observed at the Tevatron. In view of these
developments and the quickly approaching start of the LHC, we explore the
allowed region in observable space for CP violation in $B^0_d \to D^+ D^-$,
perform theoretical estimates of the relevant hadronic penguin parameters and
observables, and address questions both about the most promising strategies for
the extraction of CP-violating phases and about the interplay with other
measurements of CP violation and the search for new physics. As far as the
latter aspect is concerned, we point out that the $B^0_{q} \to D_{q}^+ D^-_{q}$
system provides a setting for the determination of the $B^0_q$-$\bar B^0_q$
mixing phases ($q\in\{d,s\}$) that is complementary to the conventional
$B^0_d\to J/\psi K_S$ and $B^0_s\to J/\psi \phi$ modes with respect to possible
new-physics effects in the electroweak penguin sector.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:12:51 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fleischer",
"Robert",
"",
"CERN"
]
] |
0705.4422 | Vincent Tatischeff | V. Tatischeff and M. Hernanz | Evidence for nonlinear diffusive shock acceleration of cosmic-rays in
the 2006 outburst of the recurrent nova RS Ophiuchi | Accepted for publication in ApJL | null | 10.1086/520049 | null | astro-ph | null | Spectroscopic observations of the 2006 outburst of the recurrent nova RS
Ophiuchi at both infrared (IR) and X-ray wavelengths have shown that the blast
wave has decelerated at a higher rate than predicted by the standard
test-particle adiabatic shock-wave model. Here we show that the observed
evolution of the nova remnant can be explained by the diffusive shock
acceleration of particles at the blast wave and the subsequent escape of the
highest energy ions from the shock region. Nonlinear particle acceleration can
also account for the difference of shock velocities deduced from the IR and
X-ray data. The maximum energy that accelerated electrons and protons can have
achieved in few days after outburst is found to be as high as a few TeV. Using
the semi-analytic model of nonlinear diffusive shock acceleration developed by
Berezhko & Ellison, we show that the postshock temperature of the shocked gas
measured with RXTE/PCA and Swift/XRT imply a relatively moderate acceleration
efficiency.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:17:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tatischeff",
"V.",
""
],
[
"Hernanz",
"M.",
""
]
] |
0705.4423 | Sin\'ead Keegan | Sin\'ead Keegan | Algebraic K-Theory and Partition Functions in Conformal Field Theory | 153 pages; minor changes to PhD thesis | null | null | DIAS-STP-07-09 | hep-th | null | Certain integrable models are described by pairs (X,Y) of ADET Dynkin
diagrams. At high energy these models are expected to have a conformally
invariant limit. The S-matrix of the model determines algebraic equations,
whose solutions are mapped to the central charge and scaling dimensions of the
corresponding conformal field theory. We study the equations of the (D_m,A_n)
model and find all solutions explicitly using the representation theory of Lie
algebras and related Yangians. These mathematically rigorous results are in
agreement with the expectations arising from physics. We also investigate the
overlap between certain q-hypergeometric series and modular functions. We study
a particular class of 2-fold q-hypergeometric series, denoted f_{A,B,C}. Here A
is a positive definite, symmetric, 2x2 matrix, B is a vector of length 2, and C
is a scalar, all three with rational entries. It turns out that for certain
choices of the matrix A, the function f_{A,B,C} can be made modular. We
calculate the corresponding values of B and C. It is expected that functions
f_{A,B,C} arising in this way are characters of some rational conformal field
theory. We show that this is true in at least one case.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:28:22 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 16:28:20 GMT"
}
] | 2007-09-19T00:00:00 | [
[
"Keegan",
"Sinéad",
""
]
] |
0705.4424 | Frank Kr\"uger | F. Kr\"uger, S. D. Wilson, L. Shan, S. Li, Y. Huang, H.- H. Wen, S.-C.
Zhang, Pengcheng Dai, J. Zaanen | Magnetic fluctuations in n-type high-$T_c$ superconductors reveal
breakdown of fermiology | 10 pages, 9 figures, 1 table | Phys. Rev. B 76, 094506 (2007) | 10.1103/PhysRevB.76.094506 | null | cond-mat.supr-con | null | By combining experimental measurements of the quasiparticle and dynamical
magnetic properties of optimally electron-doped Pr$_{0.88}$LaCe$_{0.12}$CuO$_4$
with theoretical calculations we demonstrate that the conventional fermiology
approach cannot possibly account for the magnetic fluctuations in these
materials. In particular, we perform tunneling experiments on the very same
sample for which a dynamical magnetic resonance has been reported recently and
use photoemission data by others on a similar sample to characterize the
fermionic quasiparticle excitations in great detail. We subsequently use this
information to calculate the magnetic response within the conventional
fermiology framework as applied in a large body of work for the hole-doped
superconductors to find a profound disagreement between the theoretical
expectations and the measurements: this approach predicts a step-like feature
rather than a sharp resonance peak, it underestimates the intensity of the
resonance by an order of magnitude, it suggests an unreasonable temperature
dependence of the resonance, and most severely, it predicts that most of the
spectral weight resides in incommensurate wings which are a key feature of the
hole-doped cuprates but have never been observed in the electron-doped
counterparts. Our findings strongly suggest that the magnetic fluctuations
reflect the quantum-mechanical competition between antiferromagnetic and
superconducting orders.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:28:54 GMT"
}
] | 2007-09-11T00:00:00 | [
[
"Krüger",
"F.",
""
],
[
"Wilson",
"S. D.",
""
],
[
"Shan",
"L.",
""
],
[
"Li",
"S.",
""
],
[
"Huang",
"Y.",
""
],
[
"Wen",
"H. - H.",
""
],
[
"Zhang",
"S. -C.",
""
],
[
"Dai",
"Pengcheng",
""
],
[
"Zaanen",
"J.",
""
]
] |
0705.4425 | Marianna Safronova | E. Iskrenova-Tchoukova, M. S. Safronova, (University of Delaware), and
U. I. Safronova (University of Nevada, Reno) | High-precision study of Cs polarizabilities | 19 pages | null | null | null | physics.atom-ph | null | We present results of the first-principles calculation of Cs dipole static
polarizabilities for the Ns (N = 6 - 12), Np_j (N = 6 - 10), and Nd_j (N = 5 -
10) states using the relativistic all-order method. In our implementation of
the all-order method, single and double excitations of Dirac-Fock wave
functions are included to all orders in perturbation theory. Additional
calculations are carried out for the dominant terms and the uncertainties of
our final values are estimated for all states. A comprehensive review of the
existing theoretical and experimental studies of the Cs polarizabilities is
also carried out. Our results are compared with other values where they are
available. These calculations provide a theoretical benchmark for a large
number of Cs polarizabilities.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:42:01 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Iskrenova-Tchoukova",
"E.",
"",
"University of Nevada, Reno"
],
[
"Safronova",
"M. S.",
"",
"University of Nevada, Reno"
],
[
"Safronova",
"U. I.",
"",
"University of Nevada, Reno"
]
] |
0705.4426 | Nelson Nunes | John D. Barrow and N. J. Nunes | Dynamics of Logamediate Inflation | 7 pages, 5 figures. Extended introduction | Phys.Rev.D76:043501,2007 | 10.1103/PhysRevD.76.043501 | DAMTP-2007-49 | astro-ph gr-qc | null | A computation of the inflationary observables n_{s} and r is made for
`logamediate' inflation where the cosmological scale factor expands as $a=\exp
(A(\ln t)^{\lambda})$, and is compared to their predicted values in the
intermediate inflationary theory, where $a=\exp (Bt^{f})$. Both versions prove
to be consistent with observational measurements of the cosmic background
radiation. It is shown that the dynamics of a single inflaton field can be
mimicked by a system of several fields in an analogous manner to that created
by the joint evolution of the fields in assisted power-law inflation.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:42:21 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 13:04:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Barrow",
"John D.",
""
],
[
"Nunes",
"N. J.",
""
]
] |
0705.4427 | Dietrich Stauffer | M. A. Sumour, A. H. El-Astal, M. M. Shabat, and M. A. Radwan | Simulation of Demographic Change in Palestinian Territories | For Int. J. Mod. Phys. C 18, issue 11; 9 pages including figures and
program | null | 10.1142/S0129183107011686 | null | q-bio.PE | null | Mortality, birth rates and retirement play a major role in demographic
changes. In most cases, mortality rates decreased in the past century without
noticeable decrease in fertility rates, this leads to a significant increase in
population growth. In many poor countries like Palestinian territories the
number of births has fallen and the life expectancy increased.
In this article we concentrate on measuring, analyzing and extrapolating the
age structure in Palestine a few decades ago into future. A Fortran program has
been designed and used for the simulation and analysis of our statistical data.
This study of demographic change in Palestine has shown that Palestinians will
have in future problems as the strongest age cohorts are the above-60-year
olds. We therefore recommend the increase of both the retirement age and women
employment.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:45:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sumour",
"M. A.",
""
],
[
"El-Astal",
"A. H.",
""
],
[
"Shabat",
"M. M.",
""
],
[
"Radwan",
"M. A.",
""
]
] |
0705.4428 | Harvey Gould | Jason M. Amini, Charles T. Munger Jr., and Harvey Gould | Electron electric dipole moment experiment using electric-field
quantized slow cesium atoms | 9 pages, 8 figures, accepted for publication in Phys. Rev. A | Int.J.Mod.Phys.D16:2337-2342,2008 | 10.1142/S0218271807011395 | null | physics.atom-ph | null | A proof-of-principle electron electric dipole moment (e-EDM) experiment using
slow cesium atoms, nulled magnetic fields, and electric field quantization has
been performed. With the ambient magnetic fields seen by the atoms reduced to
less than 200 pT, an electric field of 6 MV/m lifts the degeneracy between
states of unequal mF and, along with the low (approximately 3 m/s) velocity,
suppresses the systematic effect from the motional magnetic field. The low
velocity and small residual magnetic field have made it possible to induce
transitions between states and to perform state preparation, analysis, and
detection in regions free of applied static magnetic and electric fields. This
experiment demonstrates techniques that may be used to improve the e-EDM limit
by two orders of magnitude, but it is not in itself a sensitive e-EDM search,
mostly due to limitations of the laser system.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:51:16 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Amini",
"Jason M.",
""
],
[
"Munger",
"Charles T.",
"Jr."
],
[
"Gould",
"Harvey",
""
]
] |
0705.4429 | Stefano Marino | Stefano Marino | A successive sub-grouping method for multiple sequence alignments
analysis | 11 pages, 7 figures, the M_Al program is downloadable at
http://xoomer.alice.it/marinostefano/ | null | null | null | q-bio.OT q-bio.QM | null | A novel approach to protein multiple sequence alignment is discussed:
substantially this method counterparts with substitution matrix based methods
(like Blosum or PAM based methods), and implies a more deterministic approach
to chemical/physical sub-grouping of amino acids . Amino acids (aa) are divided
into sub-groups with successive derivations, that result in a clustering based
on the considered property. The properties can be user defined or chosen
between default schemes, like those used in the analysis described here.
Starting from an initial set of the 20 naturally occurring amino acids, they
are successively divided on the basis of their polarity/hydrophobic index, with
increasing resolution up to four level of subdivision. Other schemes of
subdivision are possible: in this thesis work it was employed also a scheme
based on physical/structural properties (solvent exposure, lateral chain
mobility and secondary structure tendency), that have been compared to the
chemical scheme with testing purposes. In the method described in this chapter,
the total score for each position in the alignment accounts for different
degree of similarity between amino acids. The scoring value result form the
contribution of each level of selectivity for every individual property
considered. Simply the method (called M_Al) analyse the n sequence alignment
position per position and assigns a score which have contributes by aa identity
plus a composed valuation of the chemical or of the structural affinity between
the n aligned amino acids. This method has been implemented in a series of
programs written in python language; these programs have been tested in some
biological cases, with benchmark purposes.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 16:55:59 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 21:51:07 GMT"
},
{
"version": "v3",
"created": "Thu, 7 Jun 2007 17:34:11 GMT"
}
] | 2007-06-07T00:00:00 | [
[
"Marino",
"Stefano",
""
]
] |
0705.4430 | Spiro K. Antiochos | S. K. Antiochos, C. R. DeVore, J. T. Karpen, and Z. Mikic | Structure and Dynamics of the Sun's Open Magnetic Field | 26 pages, 6 figures | null | 10.1086/522489 | null | astro-ph | null | The solar magnetic field is the primary agent that drives solar activity and
couples the Sun to the Heliosphere. Although the details of this coupling
depend on the quantitative properties of the field, many important aspects of
the corona - solar wind connection can be understood by considering only the
general topological properties of those regions on the Sun where the field
extends from the photosphere out to interplanetary space, the so-called open
field regions that are usually observed as coronal holes. From the simple
assumptions that underlie the standard quasi-steady corona-wind theoretical
models, and that are likely to hold for the Sun, as well, we derive two
conjectures on the possible structure and dynamics of coronal holes: (1)
Coronal holes are unique in that every unipolar region on the photosphere can
contain at most one coronal hole. (2) Coronal holes of nested polarity regions
must themselves be nested. Magnetic reconnection plays the central role in
enforcing these constraints on the field topology. From these conjectures we
derive additional properties for the topology of open field regions, and
propose several observational predictions for both the slowly varying and
transient corona/solar wind.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:09:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Antiochos",
"S. K.",
""
],
[
"DeVore",
"C. R.",
""
],
[
"Karpen",
"J. T.",
""
],
[
"Mikic",
"Z.",
""
]
] |
0705.4431 | Klaus Larjo | Vijay Balasubramanian, Bartlomiej Czech, Donald Marolf, Klaus Larjo
and Joan Simon | Quantum geometry and gravitational entropy | 29 pages, 2 figures; references added | JHEP 0712:067,2007 | 10.1088/1126-6708/2007/12/067 | null | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Most quantum states have wavefunctions that are widely spread over the
accessible Hilbert space and hence do not have a good description in terms of a
single classical geometry. In order to understand when geometric descriptions
are possible, we exploit the AdS/CFT correspondence in the half-BPS sector of
asymptotically AdS_5 x S^5 universes. In this sector we devise a
"coarse-grained metric operator" whose eigenstates are well described by a
single spacetime topology and geometry. We show that such half-BPS universes
have a non-vanishing entropy if and only if the metric is singular, and that
the entropy arises from coarse-graining the geometry. Finally, we use our
entropy formula to find the most entropic spacetimes with fixed asymptotic
moments beyond the global charges.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:31:00 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Jan 2009 17:36:49 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Balasubramanian",
"Vijay",
""
],
[
"Czech",
"Bartlomiej",
""
],
[
"Marolf",
"Donald",
""
],
[
"Larjo",
"Klaus",
""
],
[
"Simon",
"Joan",
""
]
] |
0705.4432 | Stefan Kukulies | Stefan Kukulies | On Shimura curves in the Schottky locus | 23 pages, shortened version of my PhD thesis | null | null | null | math.AG math.NT | null | We show that a given rational Shimura curve Y with strictly maximal Higgs
field in the moduli space of g-dimensional abelian varieties does not
generically intersect the Schottky locus for large g.
We achieve this by using a result of Viehweg and Zuo which says that if Y
parameterizes a family of curves of genus g, then the corresponding family of
Jacobians is isogenous over Y to the g-fold product of a modular family of
elliptic curves. After reducing the situation from the field of complex numbers
to a finite field, we will see, combining the Weil and Sato-Tate conjectures,
that this is impossible for large genus g.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:10:38 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Apr 2008 17:30:05 GMT"
}
] | 2008-04-07T00:00:00 | [
[
"Kukulies",
"Stefan",
""
]
] |
0705.4433 | Klaus Larjo | Klaus Larjo | On the existence of supergravity duals to D1--D5 CFT states | 22 pages, 2 figures. v2 : references added, typos corrected | JHEP 0707:041,2007 | 10.1088/1126-6708/2007/07/041 | null | hep-th | null | We define a metric operator in the 1/2-BPS sector of the D1-D5 CFT, the
eigenstates of which have a good semi-classical supergravity dual; the
non-eigenstates cannot be mapped to semi-classical gravity duals. We also
analyse how the data defining a CFT state manifests itself in the gravity side,
and show that it is arranged into a set of multipoles. Interestingly, we find
that quantum mechanical interference in the CFT can have observable
manifestations in the semi-classical gravity dual. We also point out that the
multipoles associated to the normal statistical ensemble fluctuate wildly,
indicating that the mixed thermal state should not be associated to a
semi-classical geometry.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:17:38 GMT"
},
{
"version": "v2",
"created": "Fri, 15 Jun 2007 17:01:32 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Larjo",
"Klaus",
""
]
] |
0705.4434 | Tomaso Belloni | Tomaso Belloni (INAF - Osservatorio Astronomico di Brera, Merate,
Italy) | Accretion onto black holes and relativistic jets | 4 pages, 2 figures. To appear on Mem. S.A.It, Proceedings of the 51st
national conference of S.A.It | Mem.Soc.Ast.It.75:282,2004 | null | null | astro-ph | null | Relativistic jets from Active Galactic Nuclei are known since decades, but
the study of the connection between accretion and ejection in these systems is
hampered by the long time scales associated to these events. The past decade
has seen a rapid advancement due to the observation of similar radio jets in
galactic X-ray binaries, where the time scales are much shorter. A clear
connection between accretion and ejection has been found for these systems,
together with a solid characterization of the phenomenological properties of
their outbursts. This wealth of new results has led to a detailed comparison
between X-ray binaries and AGN, from which a number of correlations and scaling
laws has been established. Here I briefly review the current observational
status.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:21:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Belloni",
"Tomaso",
"",
"INAF - Osservatorio Astronomico di Brera, Merate,\n Italy"
]
] |
0705.4435 | Kliment I. Kugel | A.O. Sboychakov, K.I. Kugel, and A.L. Rakhmanov | Phase separation in a two-band model for strongly correlated electrons | 14 pages, 5 figures, RevTeX | null | 10.1103/PhysRevB.76.195113 | null | cond-mat.str-el | null | The two-band Hubbard model is used to analyze a possibility of a non-uniform
charge distribution in a strongly correlated electron system with two types of
charge carriers. It is demonstrated that in the limit of strong on-site Coulomb
repulsion, such a system has a tendency to phase separation into the regions
with different charge densities even in the absence of magnetic or any other
ordering. This tendency is especially pronounced if the ratio of the bandwidths
is large enough. The characteristic size of inhomogeneities is estimated
accounting for the surface energy and the electrostatic energy related to the
charge imbalance.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:22:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sboychakov",
"A. O.",
""
],
[
"Kugel",
"K. I.",
""
],
[
"Rakhmanov",
"A. L.",
""
]
] |
0705.4436 | Adrian Sotomayor | S. Andrea, A. Restuccia and A. Sotomayor | New non-local SUSY KdV conservation laws from a recursive gradient
algorithm | 22 pages | null | null | null | hep-th | null | A complete proof of the recursive gradient approach is presented. It gives a
construction of all the hierarchy structures of N=1 Super KdV, including the
non-local one. A precise definition of the ring of superfields involved in the
non-local construction is given. In particular, new non-local conserved
quantities of N=1 Super KdV are found.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:41:46 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Andrea",
"S.",
""
],
[
"Restuccia",
"A.",
""
],
[
"Sotomayor",
"A.",
""
]
] |
0705.4437 | M. A. Gonzalez Leon | M.A. Gonzalez Leon and J.L. Hernandez Pastora | On the Jacobi-Metric Stability Criterion | 14 pages, no figures | null | null | null | math-ph math.MP | null | We investigate the exact relation existing between the stability equation for
the solutions of a mechanical system and the geodesic deviation equation of the
associated geodesic problem in the Jacobi metric constructed via the
Maupertuis-Jacobi Principle. We conclude that the dynamical and geometrical
approaches to the stability/instability problem are not equivalent.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:33:20 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Leon",
"M. A. Gonzalez",
""
],
[
"Pastora",
"J. L. Hernandez",
""
]
] |
0705.4438 | Denis Boyer | M.C. Santos, D. Boyer, O. Miramontes, G.M. Viswanathan, E.P. Raposo,
J.L. Mateos, M.G.E. da Luz | The origin of power-law distributions in deterministic walks: the
influence of landscape geometry | 7 pages, 11 figures. To appear in Phys. Rev. E | null | 10.1103/PhysRevE.75.061114 | null | cond-mat.dis-nn | null | We investigate the properties of a deterministic walk, whose locomotion rule
is always to travel to the nearest site. Initially the sites are randomly
distributed in a closed rectangular ($A/L \times L)$ landscape and, once
reached, they become unavailable for future visits. As expected, the walker
step lengths present characteristic scales in one ($L \to 0$) and two ($A/L
\sim L$) dimensions. However, we find scale invariance for an intermediate
geometry, when the landscape is a thin strip-like region. This result is
induced geometrically by a dynamical trapping mechanism, leading to a power law
distribution for the step lengths. The relevance of our findings in broader
contexts -- of both deterministic and random walks -- is also briefly
discussed.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:35:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Santos",
"M. C.",
""
],
[
"Boyer",
"D.",
""
],
[
"Miramontes",
"O.",
""
],
[
"Viswanathan",
"G. M.",
""
],
[
"Raposo",
"E. P.",
""
],
[
"Mateos",
"J. L.",
""
],
[
"da Luz",
"M. G. E.",
""
]
] |
0705.4439 | Niels Lauritzen | Anders Jensen, Niels Lauritzen and Bjarke Roune | Maximal lattice free bodies, test sets and the Frobenius problem | null | null | null | null | math.CO math.OC | null | Maximal lattice free bodies are maximal polytopes without interior integral
points. Scarf initiated the study of maximal lattice free bodies relative to
the facet normals in a fixed matrix. In this paper we give an efficient
algorithm for computing the maximal lattice free bodies of an integral matrix
A. An important ingredient is a test set for a certain integer program
associated with A. This test set may be computed using algebraic methods. As an
application we generalize the Scarf-Shallcross algorithm for the
three-dimensional Frobenius problem to arbitrary dimension. In this context our
method is inspired by the novel algorithm by Einstein, Lichtblau, Strzebonski
and Wagon and the Groebner basis approach by Roune.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:44:19 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 20:52:09 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Jensen",
"Anders",
""
],
[
"Lauritzen",
"Niels",
""
],
[
"Roune",
"Bjarke",
""
]
] |
0705.4440 | Brian Weber | Xiuxiong Chen, Brian Weber | Moduli spaces of critical Riemannian metrics with L^{n/2} norm curvature
bounds | 72 pages | null | null | null | math.DG math.AP | null | We consider the moduli space of the extremal K\"ahler metrics on compact
manifolds. We show that under the conditions of two-sided total volume bounds,
$L^{n\over2}$-norm bounds on $\Riem$, and Sobolev constant bounds, this Moduli
space can be compactified by including (reduced) orbifolds with finitely many
singularities. Most of our results go through for certain other classes of
critical Riemannian metrics.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:46:31 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Chen",
"Xiuxiong",
""
],
[
"Weber",
"Brian",
""
]
] |
0705.4441 | Alejandro Gangui | Olimpia Lombardi | Philosophy and Relativity | 10 pages, Published in Spanish in "El universo de Einstein: 1905 -
annus mirabilis - 2005", Alejandro Gangui (ed.), Editorial EUDEBA, 2007
(arXiv:0705.4266). Also available at http://www.universoeinstein.com.ar/ | null | null | UEinstein/2007/21 | physics.hist-ph physics.pop-ph | null | With his General Theory of Relativity, Albert Einstein produced a revolution
in our conception of reality and of the knowledge we can obtain from it. This
revolution can be viewed from philosophy as leading to one of the great
paradigms in the history of thought which, together with the Aristotelian and
the Newtonian paradigms, embodied the different ways of conceiving the universe
and our access to it. The comparison among these three paradigms allows us to
understand how the human being has progressively lost his central place in the
cosmos, not only in physical terms, but also in an epistemic sense, regarding
his power of knowledge about reality.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:50:46 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Lombardi",
"Olimpia",
""
]
] |
0705.4442 | Dan Olteanu | Dan Olteanu and Christoph Koch and Lyublena Antova | World-set Decompositions: Expressiveness and Efficient Algorithms | 34 pages, 13 figures, extended version of ICDT'07 paper | null | null | null | cs.DB | null | Uncertain information is commonplace in real-world data management scenarios.
The ability to represent large sets of possible instances (worlds) while
supporting efficient storage and processing is an important challenge in this
context. The recent formalism of world-set decompositions (WSDs) provides a
space-efficient representation for uncertain data that also supports scalable
processing. WSDs are complete for finite world-sets in that they can represent
any finite set of possible worlds. For possibly infinite world-sets, we show
that a natural generalization of WSDs precisely captures the expressive power
of c-tables. We then show that several important decision problems are
efficiently solvable on WSDs while they are NP-hard on c-tables. Finally, we
give a polynomial-time algorithm for factorizing WSDs, i.e. an efficient
algorithm for minimizing such representations.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 17:56:06 GMT"
},
{
"version": "v2",
"created": "Wed, 9 Jan 2008 10:58:06 GMT"
}
] | 2008-01-09T00:00:00 | [
[
"Olteanu",
"Dan",
""
],
[
"Koch",
"Christoph",
""
],
[
"Antova",
"Lyublena",
""
]
] |
0705.4443 | Olena Linnyk | O. Linnyk, E. L. Bratkovskaya, W. Cassing, H. Stoecker | Charmonium dynamics in Au+Au collisions at sqrt(S)=200 GeV | 4 pages, 2 figures | Phys.Rev.C76:041901,2007 | 10.1103/PhysRevC.76.041901 | null | nucl-th hep-ph | null | The formation and suppression dynamics of J/Psi, Chi_c and Psi-Prime mesons
is studied within the HSD transport approach for Au+Au reactions at the top
RHIC energy of sqrt(S)=200 GeV. Two prominent models, which have been discussed
for more than a decade, are incorporated, i.e. the 'hadronic comover absorption
and reformation' model as well as the 'QGP threshold' scenario, and compared to
available experimental data. Our studies demonstrate that both scenarios -
compatible with experimental observation at SPS energies - fail severely at
RHIC energies. This combined analysis - together with the underestimation of
charm elliptic flow - proves that the dynamics of c, c-bar quarks are dominated
by partonic interactions in the strong QGP (sQGP) and can neither be modeled by
'hadronic' interactions nor described appropriately by color screening alone.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:10:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Linnyk",
"O.",
""
],
[
"Bratkovskaya",
"E. L.",
""
],
[
"Cassing",
"W.",
""
],
[
"Stoecker",
"H.",
""
]
] |
0705.4444 | Johannes Nordstr\"om | Johannes Nordstr\"om | Deformations of asymptotically cylindrical G_2 manifolds | 31 pages, corrected proof of proposition 6.23 | Math. Proc. Camb. Phil. Soc. 145 (2008) 311-348 | 10.1017/S0305004108001333 | null | math.DG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We prove that for a 7-dimensional manifold M with cylindrical ends the moduli
space of exponentially asymptotically cylindrical torsion-free G_2 structures
is a smooth manifold (if non-empty), and study some of its local properties. We
also show that the holonomy of the induced metric of an exponentially
asymptotically cylindrical G_2 manifold M is exactly G_2 if and only if its
fundamental group is finite and neither M nor any double cover of M is
homeomorphic to a cylinder.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:10:01 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Nov 2007 18:00:26 GMT"
},
{
"version": "v3",
"created": "Wed, 11 Mar 2009 18:23:01 GMT"
}
] | 2009-03-11T00:00:00 | [
[
"Nordström",
"Johannes",
""
]
] |
0705.4445 | Santo Fortunato Dr | Santo Fortunato | Quality functions in community detection | 10 pages, 4 figures, invited paper to appear in the Proceedings of
SPIE International Conference "Fluctuations and Noise 2007", Florence, Italy,
20-24 May, 2007 | null | 10.1117/12.726703 | null | physics.soc-ph | null | Community structure represents the local organization of complex networks and
the single most important feature to extract functional relationships between
nodes. In the last years, the problem of community detection has been
reformulated in terms of the optimization of a function, the Newman-Girvan
modularity, that is supposed to express the quality of the partitions of a
network into communities. Starting from a recent critical survey on modularity
optimization, pointing out the existence of a resolution limit that poses
severe limits to its applicability, we discuss the general issue of the use of
quality functions in community detection. Our main conclusion is that quality
functions are useful to compare partitions with the same number of modules,
whereas the comparison of partitions with different numbers of modules is not
straightforward and may lead to ambiguities.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:20:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fortunato",
"Santo",
""
]
] |
0705.4446 | Juan Pablo Paz | Juan Pablo Paz | Einstein against quantum mechanics: randomness, ignorance and our
ignorance about randomness | 21 pages, Published in Spanish in "El universo de Einstein: 1905 -
annus mirabilis - 2005", Alejandro Gangui (ed.), Editorial EUDEBA, 2007
(arXiv:0705.4266). Also available at http://www.universoeinstein.com.ar/ | null | null | UEinstein/2007/12 | physics.hist-ph physics.pop-ph | null | Albert Einstein made fundamental contributions to the development of quantum
mechanics. However, he was never satisfied with the quantum worldview. In fact,
during most of his life he attempted to find inconsistencies and paradoxes
within quantum mechanics. His famous quote "God does not play dice" shows how
disturbing was to Einstein one of the most important aspects of quantum
mechanics: non-determinism. In this paper we will present the basic concepts of
quantum mechanics, we will describe Einstein's attempts to destroy it and we
will discuss why we can nowadays state that, in this regard, Albert Einstein
was not right.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:22:30 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Paz",
"Juan Pablo",
""
]
] |
0705.4447 | Martina Hentschel | Martina Hentschel, Georg Roeder, Denis Ullmo | Many-body effects in the mesoscopic x-ray edge problem | 9 pages, 3 figures, Proceedings ``Quantum Mechanics and Chaos''
(Osaka 2006) | Prog. Theor. Phys. Suppl. 166 (2007), 143-151 | 10.1143/PTPS.166.143 | null | cond-mat.mes-hall | null | Many-body phenomena, a key interest in the investigation of bulk solid state
systems, are studied here in the context of the x-ray edge problem for
mesoscopic systems. We investigate the many-body effects associated with the
sudden perturbation following the x-ray excitation of a core electron into the
conduction band. For small systems with dimensions at the nanoscale we find
considerable deviations from the well-understood metallic case where Anderson
orthogonality catastrophe and the Mahan-Nozieres-DeDominicis response cause
characteristic deviations of the photoabsorption cross section from the naive
expectation. Whereas the K-edge is typically rounded in metallic systems, we
find a slightly peaked K-edge in generic mesoscopic systems with
chaotic-coherent electron dynamics. Thus the behavior of the photoabsorption
cross section at threshold depends on the system size and is different for the
metallic and the mesoscopic case.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:32:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hentschel",
"Martina",
""
],
[
"Roeder",
"Georg",
""
],
[
"Ullmo",
"Denis",
""
]
] |
0705.4448 | Maria Chiara Brambilla | Maria Chiara Brambilla and Giorgio Ottaviani | On partial polynomial interpolation | 34 pages, 2 tables, revised version: different proof of Theorem 4.1,
Section 4 significantly changed, Appendix added | Linear Algebra and its Applications 435, (2011) 6, 1415-1445 | null | null | math.AG math.NA | null | The Alexander-Hirschowitz theorem says that a general collection of $k$
double points in ${\bf P}^n$ imposes independent conditions on homogeneous
polynomials of degree $d$ with a well known list of exceptions. We generalize
this theorem to arbitrary zero-dimensional schemes contained in a general union
of double points. We work in the polynomial interpolation setting. In this
framework our main result says that the affine space of polynomials of degree
$\le d$ in $n$ variables, with assigned values of any number of general linear
combinations of first partial derivatives, has the expected dimension if $d\neq
2$ with only five exceptional cases. If $d=2$ the exceptional cases are fully
described.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:28:00 GMT"
},
{
"version": "v2",
"created": "Mon, 11 Jun 2007 14:08:02 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Dec 2007 17:45:33 GMT"
}
] | 2012-11-01T00:00:00 | [
[
"Brambilla",
"Maria Chiara",
""
],
[
"Ottaviani",
"Giorgio",
""
]
] |
0705.4449 | Marek Szydlowski | Jakub Mielczarek, Marek Szydlowski | Relic gravitons as the observable for Loop Quantum Cosmology | RevTeX4, 10 pages, 4 figures; v2: extended, more clarification on
quantum corrections | Phys.Lett.B657:20-26,2007 | 10.1016/j.physletb.2007.10.011 | null | gr-qc | null | In this paper we investigate tensor modes of perturbations in the universe
governed by Loop Quantum Cosmology. We derive the equation for tensor modes and
investigate numerically effects of quantum corrections. This investigation
reveals that the region of super-adiabatic amplification of tensor modes is
smaller in comparison with the classical case. Neglecting quantum corrections
to the equation for tensor modes and holding underlying loop dynamics we study
analytically the creation of gravitons. We calculate the power spectrum of
tensor perturbations during the super-inflationary phase induced by Loop
Quantum Gravity. The main result obtained is the spectrum of gravitons,
produced in the transition from the quantum to classical regime of the
Universe. Obtained spectrum is characterized by a hard branch. The numerical
investigation shows the strong dependence of $\nu_{\text{max}}$ frequency with
respect to quantum numbers. The parameter
$\Omega_{\text{gw}}(\nu_{\text{max}})$ approaches even to $\sim 10^{-1}$ for
highest frequencies. We compare our results with recent constraints from the
Laser Interferometer Gravitational-wave Observatory (LIGO) and find that it is
possible to test the quantum effects in the early Universe.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:34:58 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Sep 2007 07:55:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mielczarek",
"Jakub",
""
],
[
"Szydlowski",
"Marek",
""
]
] |
0705.4450 | Yury Bliokh P | Yu.A. Kravtsov, B. Bieg, and K.Yu. Bliokh | Stokes-vector evolution in a weakly anisotropic inhomogeneous medium | 16 pages, 3 figures, to appear in J. Opt. Soc. Am. A | J. Opt. Soc. Am. A 24, 3388 (2007). | 10.1364/JOSAA.24.003388 | null | physics.optics physics.plasm-ph | null | Equation for evolution of the four-component Stokes vector in weakly
anisotropic and smoothly inhomogeneous media is derived on the basis of
quasi-isotropic approximation of the geometrical optics method, which provides
consequent asymptotic solution of Maxwell equations. Our equation generalizes
previous results, obtained for the normal propagation of electromagnetic waves
in stratified media. It is valid for curvilinear rays with torsion and is
capable to describe normal modes conversion in the inhomogeneous media.
Remarkably, evolution of the Stokes vector is described by the
Bargmann-Michel-Telegdi equation for relativistic spin precession, whereas the
equation for the three-component Stokes vector resembles the Landau-Lifshitz
equation for spin precession in ferromegnetic systems. General theory is
applied for analysis of polarization evolution in a magnetized plasma. We also
emphasize fundamental features of the non-Abelian polarization evolution in
anisotropic inhomogeneous media and illustrate them by simple examples.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:43:12 GMT"
},
{
"version": "v2",
"created": "Sat, 11 Aug 2007 09:24:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kravtsov",
"Yu. A.",
""
],
[
"Bieg",
"B.",
""
],
[
"Bliokh",
"K. Yu.",
""
]
] |
0705.4451 | Nikolai Priezjev V. | Nikolai V. Priezjev | Effect of surface roughness on rate-dependent slip in simple fluids | 15 pages, 5 figures; submitted to J. Chem. Phys | J. Chem. Phys. 127, 144708 (2007) | 10.1063/1.2796172 | null | cond-mat.soft cond-mat.mtrl-sci | null | Molecular dynamics simulations are used to investigate the influence of
molecular-scale surface roughness on the slip behavior in thin liquid films.
The slip length increases almost linearly with the shear rate for atomically
smooth rigid walls and incommensurate structures of the liquid/solid interface.
The thermal fluctuations of the wall atoms lead to an effective surface
roughness, which makes the slip length weakly dependent on the shear rate. With
increasing the elastic stiffness of the wall, the surface roughness smoothes
out and the strong rate dependence is restored again. Both periodically and
randomly corrugated rigid surfaces reduce the slip length and its shear rate
dependence.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:44:03 GMT"
}
] | 2007-10-10T00:00:00 | [
[
"Priezjev",
"Nikolai V.",
""
]
] |
0705.4452 | Tony Rothman | Alessandro Giuliani and Tony Rothman | Absolute Stability Limit for Relativistic Charged Spheres | 25 pages, 1 figure 1 June 07: Replaced with added citations to prior
work along same lines | Gen.Rel.Grav.40:1427-1447,2008 | 10.1007/s10714-007-0539-7 | null | gr-qc | null | We find an exact solution for the stability limit of relativistic charged
spheres for the case of constant gravitational mass density and constant charge
density. We argue that this provides an absolute stability limit for any
relativistic charged sphere in which the gravitational mass density decreases
with radius and the charge density increases with radius. We then provide a
cruder absolute stability limit that applies to any charged sphere with a
spherically symmetric mass and charge distribution. We give numerical results
for all cases. In addition, we discuss the example of a neutral sphere
surrounded by a thin, charged shell.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 18:52:10 GMT"
},
{
"version": "v2",
"created": "Fri, 1 Jun 2007 15:04:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Giuliani",
"Alessandro",
""
],
[
"Rothman",
"Tony",
""
]
] |
0705.4453 | Jacek Niemiec | Jacek Niemiec, Michal Ostrowski and Martin Pohl | The inefficiency of the first-order Fermi process in UHECR production at
relativistic shocks | 4 pages, 4 figures, Proceedings of the 30th ICRC, Merida, Mexico 2007 | null | null | null | astro-ph | null | The question of the origin of ultra-high-energy cosmic rays at relativistic
shock waves is discussed in the light of results of recent Monte Carlo studies
of the first-order Fermi particle acceleration (Niemiec & Ostrowski 2006,
Niemiec et al. 2006). The models of the turbulent magnetic field near the shock
considered in these simulations include realistic features of the perturbed
magnetic field structures at the shock, which allow us to study all the field
and particle motion characteristics that are important for cosmic-ray
acceleration. Our results show that turbulent conditions near the shock, that
are consistent with the shock jump conditions, lead to substantial
modifications of the acceleration process with respect to the simplified
models, that produce wide-range power-law energy distributions, often with the
"universal" spectral index. Relativistic shocks are essentially always
superluminal, and thus they preferentially generate steep particle spectra with
cutoffs well below the maximum scattering energy, often not exceeding the
energy of the compressed background plasma ions. Thus, cosmic-ray acceleration
to very high energies at relativistic shock waves is inefficient, and such
shocks are not expected to be the sources of ultra-high-energy particles.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:13:53 GMT"
}
] | 2007-05-31T00:00:00 | [
[
"Niemiec",
"Jacek",
""
],
[
"Ostrowski",
"Michal",
""
],
[
"Pohl",
"Martin",
""
]
] |
0705.4454 | Sam Thompson III | S.H. Thompson, G. Brown, P.A. Rikvold, M.A. Novotny | Two Modes of Magnetization Switching in a Simulated Iron Nanopillar in
an Obliquely Oriented Field | 19 pages, 7 figures | J. Phys.: Condens. Matter 22 (2010) 236001 | 10.1088/0953-8984/22/23/236001 | null | cond-mat.stat-mech | null | Finite-temperature micromagnetics simulations are employed to study the
magnetization-switching dynamics driven by a field applied at an angle to the
long axis of an iron nanopillar. A bi-modal distribution in the switching times
is observed, and evidence for two competing modes of magnetization-switching
dynamics is presented. For the conditions studied here, temperature $T = 20$ K
and the reversal field 3160 Oe at an angle of 75$^\circ$ to the long axis,
approximately 70% of the switches involve unstable decay (no free-energy
barrier) and 30% involve metastable decay (a free-energy barrier is crossed).
The latter are indistinguishable from switches which are constrained to start
at a metastable free-energy minimum. Competition between unstable and
metastable decay could greatly complicate applications involving magnetization
switches near the coercive field.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:20:39 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Thompson",
"S. H.",
""
],
[
"Brown",
"G.",
""
],
[
"Rikvold",
"P. A.",
""
],
[
"Novotny",
"M. A.",
""
]
] |
0705.4455 | Dr. Mario Rabinowitz | Mario Rabinowitz | Is Quantum Mechanics Incompatible with Newton's First Law | Paper has been revised to conform to published version | Int'l Jour. of Theoretical Physics Vol.47 No.4 936-948 (2008) | 10.1007/s10773-007-9519-7 | null | physics.gen-ph physics.class-ph | null | Quantum mechanics (QM) clearly violates Newton's First Law of Motion (NFLM)
in the quantum domain for one of the simplest problems, yielding an effect in a
force-free region much like the Aharonov-Bohm effect. In addition, there is an
incompatibility between the predictions of QM in the classical limit, and that
of classical mechanics (CM) with respect to NFLM. A general argument is made
that such a disparity may be found commonly for a wide variety of quantum
predictions in the classical limit. Alternatives to the Schrodinger equation
are considered that might avoid this problem. The meaning of the classical
limit is examined. Critical views regarding QM by Schrodinger, Bohm, Bell,
Clauser, and others are presented to provide a more complete perspective.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:20:45 GMT"
},
{
"version": "v2",
"created": "Fri, 29 Jun 2007 01:00:09 GMT"
},
{
"version": "v3",
"created": "Fri, 11 Apr 2008 00:14:46 GMT"
}
] | 2008-04-11T00:00:00 | [
[
"Rabinowitz",
"Mario",
""
]
] |
0705.4456 | Liz Humphreys Dr | E. M. L. Humphreys | Submillimeter and Millimeter Masers | 10 pages, 2 figures, 2 tables; to appear in conference proceedings of
IAU 242: Astrophysical Masers and Their Environments, held in Alice Springs,
Australia (March 2007) | null | 10.1017/S1743921307013622 | null | astro-ph | null | Despite theoretical predictions of the existence of many submillimeter
masers, and some pioneering observational discoveries over the past few
decades, these lines have remained relatively unstudied due to (i) challenges
associated with observing at shorter wavelength; and, (ii) lack of possibility
of high (< 14'' at 345 GHz) angular resolution observations. With the advent of
the SMA, the first submillimeter imaging array capable of sub-arcsecond
resolution, APEX, and the promise of ALMA, opportunities are opening for
performing new science with millimeter/submillmeter masers. In this talk, I
will review recent work in the field - including extragalactic water millimeter
masers, hydrogen recombination masers, submillimeter masers in star-forming
regions, and in the envelopes of evolved stars - and discuss prospects for the
future.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:58:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Humphreys",
"E. M. L.",
""
]
] |
0705.4457 | Andres Escala | Andres Escala (KIPAC, Stanford U./Slac) | Towards a Comprehensive Fueling-Controlled Theory on the Growth of
Massive Black Holes and Host Spheroids | 12 pages, figures, submited to ApJ, email: [email protected] | Astrophys.J.671:1264-1271,2007 | 10.1086/523092 | null | astro-ph | null | We study the relation between nuclear massive black holes and their host
spheroid gravitational potential. Using AMR numerical simulations, we analyze
how gas is transported in the nuclear (central kpc) regions of galaxies. We
study the gas fueling onto the inner accretion disk (sub-pc scale) and the star
formation in a massive nuclear disk like those generally found in
proto-spheroids (ULIRGs, SCUBA Galaxies). These sub-pc resolution simulation of
gas fueling that is mainly depleted by star formation naturally satisfy the
`M_BH - $M_virial' relation, with a scatter considerably less than the observed
one. We found a generalized version of Kennicutt-Schmidt Law for starbursts is
satisfied, in which the total gas depletion rate (dot{M}_gas = dot{M}_BH +
dot{M}_SF) is the one that scales as M_gas/t_orbital. We also found that the
`M_BH - sigma' relation is a byproduct of the `M_BH - M_virial' relation in the
fueling controlled scenario.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:29:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Escala",
"Andres",
"",
"KIPAC, Stanford U./Slac"
]
] |
0705.4458 | Philip Bechtle | P. Bechtle (for the BaBar Collaboration) | Radiative $b\to d$ Penguins | Prepared for the Rencontres de Moriond EW 2007. 6 pages, 7 figures, 2
tables, replacement due to missing fonts in feynman diagrams | null | null | null | hep-ex | null | This article gives an overview of the recent searches and measurements of
$b\to d$ penguin transitions with the BaBar experiment. The branching fraction
of these decays in the Standard Model (SM) is expected to be a factor of 10 or
more lower than the corresponding $b\to s$ penguin transitions, but a deviation
from the SM prediction would be an equally striking sign of new physics. The
exclusive decay $B\to\pi\ell\ell$ is searched by BaBar with no excess over the
background found. The BaBar measurement of $B\to(\rho,\omega)\gamma$ provides
the first evidence of $B^+\to\rho^+\gamma$, is in good agreement with the
previous Belle results and provides a measurement of $|V_{td}/V_{ts}|$
independent of the one from $B_s$ mixing. No deviation from the SM is found.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:38:54 GMT"
},
{
"version": "v2",
"created": "Thu, 31 May 2007 09:58:16 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Bechtle",
"P.",
"",
"for the BaBar Collaboration"
]
] |
0705.4459 | Jacek Niemiec | Jacek Niemiec and Martin Pohl | Magnetic turbulence production by streaming cosmic rays upstream of SNR
shocks | 4 pages, 3 figures, Proceedings of the 30th ICRC, Merida, Mexico 2007 | AIPConf.Proc.921:405-406,2007 | 10.1063/1.2757374 | null | astro-ph | null | We present preliminary results of Particle-In-Cell simulations of magnetic
turbulence production by isotropic cosmic-ray ions streaming upstream of
supernova remnant shocks. The studies aim at testing the MHD predictions by
Bell (2004, 2005) of a strong amplification of short-wavelength nonresonant
wave modes and at studying the subsequent evolution of the magnetic turbulence
and its backreaction on cosmic ray trajectories. The detailed knowledge of the
upstream turbulence properties is crucial to ascertain all aspects of the shock
acceleration process - the transport properties of cosmic rays, the shock
structure, thermal particle injection and heating processes. An amplification
of magnetic field would also facilitate the acceleration of particles beyond
the "knee" in the cosmic-ray spectrum. Our kinetic approach is particularly
suited to address the backreaction on the cosmic rays, and it allows us to test
Bell's prediction of the eventual formation of extended filamentary structure
in the cosmic-ray distribution and also to arrive at a reliable estimate of the
total saturation magnetic-field level. The parameters chosen for the
simulations are favorable for the rapid excitation of purely growing modes. We
confirm the generation of the turbulent magnetic field due to the drift of
cosmic-ray ions in the upstream plasma, but show that the growth rate of the
field perturbations is much slower than estimated using the MHD approach and
the amplitude of the turbulence saturates at about dB/B~1. The magnetic field
also remains below equipartition with the upstream plasma.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:39:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Niemiec",
"Jacek",
""
],
[
"Pohl",
"Martin",
""
]
] |
0705.4460 | Victor Gurarie | J. Levinsen, N. Cooper, V. Gurarie | Strongly-resonant p-wave superfluids | null | Phys. Rev. Lett. 99, 210402 (2007) | 10.1103/PhysRevLett.99.210402 | null | cond-mat.supr-con | null | We study theoretically a dilute gas of identical fermions interacting via a
p-wave resonance. We show that, depending on the microscopic physics, there are
two distinct regimes of p-wave resonant superfluids, which we term "weak" and
"strong". Although expected naively to form a BCS-BEC superfluid, a
strongly-resonant p-wave superfluid is in fact unstable towards the formation
of a gas of fermionic triplets. We examine this instability and estimate the
lifetime of the p-wave molecules due to the collisional relaxation into
triplets. We discuss consequences for the experimental achievement of p-wave
superfluids in both weakly- and strongly-resonant regimes.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:51:49 GMT"
}
] | 2008-04-21T00:00:00 | [
[
"Levinsen",
"J.",
""
],
[
"Cooper",
"N.",
""
],
[
"Gurarie",
"V.",
""
]
] |
0705.4461 | Carmen Nunez | Sergio Iguri and Carmen Nunez | Coulomb integrals for the SL(2,R) WZNW model | Improved presentation. New section on spectral flow violating
correlators and computation of a four-point function | Phys.Rev.D77:066015,2008 | 10.1103/PhysRevD.77.066015 | null | hep-th | null | We review the Coulomb gas computation of three-point functions in the SL(2,R)
WZNW model and obtain explicit expressions for generic states. These amplitudes
have been computed in the past by this and other methods but the analytic
continuation in the number of screening charges required by the Coulomb gas
formalism had only been performed in particular cases. After showing that ghost
contributions to the correlators can be generally expressed in terms of Schur
polynomials we solve Aomoto integrals in the complex plane, a new set of
multiple integrals of Dotsenko-Fateev type. We then make use of monodromy
invariance to analytically continue the number of screening operators and prove
that this procedure gives results in complete agreement with the amplitudes
obtained from the bootstrap approach. We also compute a four-point function
involving a spectral flow operator and we verify that it leads to the one unit
spectral flow three-point function according to a prescription previously
proposed in the literature. In addition, we present an alternative method to
obtain spectral flow non-conserving n-point functions through well defined
operators and we prove that it reproduces the exact correlators for n=3.
Independence of the result on the insertion points of these operators suggests
that it is possible to violate winding number conservation modifying the
background charge.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 19:51:51 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jun 2007 13:26:06 GMT"
},
{
"version": "v3",
"created": "Fri, 11 Jan 2008 13:52:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Iguri",
"Sergio",
""
],
[
"Nunez",
"Carmen",
""
]
] |
0705.4462 | Nils Hasselmann | Nils Hasselmann, Andreas Sinner, and Peter Kopietz | Two-parameter scaling of correlation functions near continuous phase
transitions | 4 pages, 5 figures, revised version, to appear as Rapid Communication
in Phys.Rev.E | Phys. Rev. E 76, 040101(R) (2007) | 10.1103/PhysRevE.76.040101 | null | cond-mat.stat-mech hep-th | null | We discuss the order parameter correlation function in the vicinity of
continuous phase transitions using a two-parameter scaling form G(k) = k_c^{-2}
g(k\xi,k/k_c), where k is the wave-vector, \xi is the correlation length, and
the interaction-dependent non-universal momentum scale k_c remains finite at
the critical fixed point. The correlation function describes the entire
critical regime and captures the classical to critical crossover. One-parameter
scaling is recovered only in the limit k/k_c->0. We present an approximate
calculation of g(x,y) for the Ising universality class using the functional
renormalization group.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 16:20:16 GMT"
},
{
"version": "v2",
"created": "Fri, 10 Aug 2007 13:35:49 GMT"
},
{
"version": "v3",
"created": "Wed, 26 Sep 2007 08:52:38 GMT"
}
] | 2008-02-28T00:00:00 | [
[
"Hasselmann",
"Nils",
""
],
[
"Sinner",
"Andreas",
""
],
[
"Kopietz",
"Peter",
""
]
] |
0705.4463 | Oleg Tretiakov | O. A. Tretiakov, D. Clarke, Gia-Wei Chern, Ya. B. Bazaliy, O.
Tchernyshyov | Dynamics of domain walls in magnetic nanostrips | 4 pages, update to published version | Phys. Rev. Lett. 100, 127204 (2008) | 10.1103/PhysRevLett.100.127204 | null | cond-mat.mtrl-sci | null | We express dynamics of domain walls in ferromagnetic nanowires in terms of
collective coordinates generalizing Thiele's steady-state results. For weak
external perturbations the dynamics is dominated by a few soft modes. The
general approach is illustrated on the example of a vortex wall relevant to
recent experiments with flat nanowires. A two-mode approximation gives a
quantitatively accurate description of both the steady viscous motion of the
wall in weak magnetic fields and its oscillatory behavior in moderately high
fields above the Walker breakdown.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 16:01:23 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Dec 2007 21:38:49 GMT"
},
{
"version": "v3",
"created": "Thu, 14 Feb 2008 19:32:12 GMT"
}
] | 2008-03-31T00:00:00 | [
[
"Tretiakov",
"O. A.",
""
],
[
"Clarke",
"D.",
""
],
[
"Chern",
"Gia-Wei",
""
],
[
"Bazaliy",
"Ya. B.",
""
],
[
"Tchernyshyov",
"O.",
""
]
] |
0705.4464 | Igor Zutic | A. G. Petukhov, Igor Zutic, Steven C. Erwin | Thermodynamics of carrier-mediated magnetism in semiconductors | 4 pages, 3 figures | Phys. Rev. Lett. 99, 257202 (2007) | 10.1103/PhysRevLett.99.257202 | null | cond-mat.mtrl-sci cond-mat.other | null | We propose a model of carrier-mediated ferromagnetism in semiconductors that
accounts for the temperature dependence of the carriers. The model permits
analysis of the thermodynamic stability of competing magnetic states, opening
the door to the construction of magnetic phase diagrams. As an example we
analyze the stability of a possible reentrant ferromagnetic semiconductor, in
which increasing temperature leads to an increased carrier density, such that
the enhanced exchange coupling between magnetic impurities results in the onset
of ferromagnetism as temperature is raised.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:01:46 GMT"
}
] | 2010-11-09T00:00:00 | [
[
"Petukhov",
"A. G.",
""
],
[
"Zutic",
"Igor",
""
],
[
"Erwin",
"Steven C.",
""
]
] |
0705.4465 | David Clarke | D. Clarke, G.-W. Chern, O. A. Tretiakov, O. Tchernyshyov | Dynamics of a domain wall in a magnetic nanostrip: a toy model | null | null | null | null | cond-mat.mtrl-sci | null | In this report we demonstrate a simple model for the motion of a vortex
domain wall in a ferromagnetic strip of submicron width under the influence of
an external magnetic field. The model exhibits three distinct dynamical
regimes. In a viscous regime at low fields the wall moves rigidly with a
velocity proportional to the field. Above a critical field the motion becomes
underdamped as the vortex moves periodically across the strip; these
oscillations are accompanied by a slow drift with a decreasing velocity. At
still higher fields the drift velocity starts rising linearly with the field
again but with a much lower mobility dv/dH than in the low-field regime. We
calculate the relevant quantities and compare them to experimentally observed
values.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 16:30:15 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Clarke",
"D.",
""
],
[
"Chern",
"G. -W.",
""
],
[
"Tretiakov",
"O. A.",
""
],
[
"Tchernyshyov",
"O.",
""
]
] |
0705.4466 | M. Leticia Rubio Puzzo PhD | M. Leticia Rubio Puzzo and Ezequiel V. Albano | A Model for Damage Spreading with Damage Healing: Monte Carlo Study of
the two Dimensional Ising Ferromagnet | 12 pages, 7 figures included | Physica A, 349, 172-182, 2005 | 10.1016/j.physa.2004.10.013 | null | cond-mat.stat-mech | null | An Ising model for damage spreading with a probability of damage healing ($q
= 1 - p$) is proposed and studied by means of Monte Carlo simulations. In the
limit $p \to 1$ the new model is mapped to the standard Ising model. It is
found that, for temperatures above the Onsager critical temperature ($T_{C}$),
there exist a no trivial finite value of $p$ that sets the critical point
($p_{c}$) for the onset of damage spreading. It is found that $p_{c}$ depends
on $T$, defining a critical curve at the border between damage spreading and
damage healing. Transitions along such curve are found to belong to the
universality class of directed percolation. The phase diagram of the model is
also evaluated showing that for large $T$ one has $p_{c} \propto (T-
T_{C})^{\alpha}$, with $\alpha = 1$. Within the phase where the damage remains
active, the stationary value of the damage depends lineally on both $p - p_{c}$
and $T - T_{C} $.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:02:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Puzzo",
"M. Leticia Rubio",
""
],
[
"Albano",
"Ezequiel V.",
""
]
] |
0705.4467 | Robert Quimby | Robert Quimby, Peter H\"oflich and J. Craig Wheeler | SN 2005hj: Evidence for Two Classes of Normal-Bright SNe Ia and
Implications for Cosmology | ApJ accepted, 31 pages | Astrophys.J.666:1083-1092,2007 | 10.1086/520527 | null | astro-ph | null | HET Optical spectra covering the evolution from about 6 days before to about
5 weeks after maximum light and the ROTSE-IIIb unfiltered light curve of the
"Branch-normal" Type Ia Supernova SN 2005hj are presented. The host galaxy
shows HII region lines at redshift of z=0.0574, which puts the peak unfiltered
absolute magnitude at a somewhat over-luminous -19.6. The spectra show weak and
narrow SiII lines, and for a period of at least 10 days beginning around
maximum light these profiles do not change in width or depth and they indicate
a constant expansion velocity of ~10,600 km/s. We analyzed the observations
based on detailed radiation dynamical models in the literature. Whereas delayed
detonation and deflagration models have been used to explain the majority of
SNe Ia, they do not predict a long velocity plateau in the SiII minimum with an
unvarying line profile. Pulsating delayed detonations and merger scenarios form
shell-like density structures with properties mostly related to the mass of the
shell, M_shell, and we discuss how these models may explain the observed SiII
line evolution; however, these models are based on spherical calculations and
other possibilities may exist. SN 2005hj is consistent with respect to the
onset, duration, and velocity of the plateau, the peak luminosity and, within
the uncertainties, with the intrinsic colors for models with M_shell=0.2 M_sun.
Our analysis suggests a distinct class of events hidden within the
Branch-normal SNe Ia. If the predicted relations between observables are
confirmed, they may provide a way to separate these two groups. We discuss the
implications of two distinct progenitor classes on cosmological studies
employing SNe Ia, including possible differences in the peak luminosity to
light curve width relation.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:18:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Quimby",
"Robert",
""
],
[
"Höflich",
"Peter",
""
],
[
"Wheeler",
"J. Craig",
""
]
] |
0705.4468 | Guang-You Qin | G.Y. Qin, J. Ruppert, S. Turbide, C. Gale and S. Jeon | Nuclear Suppression of Jets and R_AA at the LHC | 2 pages, 1 figure, contributed to Workshop on Heavy Ion Collisions at
the LHC: Last Call for Predictions, Geneva, Switzerland, 14 May - 8 Jun 2007 | null | null | null | hep-ph nucl-th | null | The nuclear modification factor R_AA for charged hadron production at the LHC
is predicted from jet energy loss induced by gluon bremsstrahlung. The Arnold,
Moore, and Yaffe formalism is used, together with an ideal hydrodynamical
model.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 21:11:27 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Qin",
"G. Y.",
""
],
[
"Ruppert",
"J.",
""
],
[
"Turbide",
"S.",
""
],
[
"Gale",
"C.",
""
],
[
"Jeon",
"S.",
""
]
] |
0705.4469 | Oleg Kochukhov | Oleg Kochukhov, Saul J. Adelman, Austin F. Gulliver, Nikolai Piskunov | Weather in stellar atmosphere: the dynamics of mercury clouds in alpha
Andromedae | 10 pages, 2 figures; to be published in Nature Physics | null | 10.1038/nphys648 | null | astro-ph | null | The formation of long-lasting structures at the surfaces of stars is commonly
ascribed to the action of strong magnetic fields. This paradigm is supported by
observations of evolving cool spots in the Sun and active late-type stars, and
stationary chemical spots in the early-type magnetic stars. However, results of
our seven-year monitoring of mercury spots in non-magnetic early-type star
alpha Andromedae show that the picture of magnetically-driven structure
formation is fundamentally incomplete. Using an indirect stellar surface
mapping technique, we construct a series of 2-D images of starspots and
discover a secular evolution of the mercury cloud cover in this star. This
remarkable structure formation process, observed for the first time in any
star, is plausibly attributed to a non-equilibrium, dynamical evolution of the
heavy-element clouds created by atomic diffusion and may have the same
underlying physics as the weather patterns on terrestrial and giant planets.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:19:52 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Kochukhov",
"Oleg",
""
],
[
"Adelman",
"Saul J.",
""
],
[
"Gulliver",
"Austin F.",
""
],
[
"Piskunov",
"Nikolai",
""
]
] |
0705.4470 | Ezequiel Vicente Albano | M. Cecilia Gimenez and Ezequiel V. Albano | Dynamic response of Ag monolayers adsorbed on Au(100) upon an
oscillatory variation of the chemical potential: A Monte Carlo simulation
study | 20 pages, 9 figures | J. Phys. Chem. C. V111, (2007) 1809 | null | null | cond-mat.stat-mech cond-mat.mtrl-sci | null | Based on the fact that the underpotential electrochemical deposition of Ag
atoms on the $Au(100)$ surface exhibits sharp first-order phase transitions at
well-defined values of the (coexistence) chemical potential ($\mu_{coex}$), we
performed extensive simulations aimed at investigating the hysteretic dynamic
behavior of the system close to coexistence upon the application of a periodic
signal of the form $\mu(t) = \mu_{coex} + \mu_{o}sin(2\Pi t/\tau) $, where
$\mu_{o}$ and $\tau$ are the amplitude and the period of the sweep,
respectively. For relatively short periods and small enough amplitudes the
system becomes trapped either at low or high Ag coverage states, as evidenced
by recording hysteresis loops. This scenario is identified as dynamically
ordered states (DOS), such that the relaxation time $(\tau_{relax})$ of the
corresponding metastable state obeys $\tau_{relax} > \tau $. On the other hand,
by properly increasing $\mu_{o}$ or/and $\tau$, one finds that the $Ag$
coverage gently follows the external drive (here $\tau_{relax} < \tau $) and
the system is said to enter into dynamically disordered states (DDS), where
hysteresis loops show almost symmetric limiting cycles. This symmetry breaking
between limiting cycles driven by an external signal is discussed in terms of
the concept of (out-of-equilibrium) Dynamic Phase Transitions between DOS and
DDS, similar to those encountered when a magnetic system is placed in the
presence of a variable external magnetic field. However, a careful finite-size
scaling study reveals that, at least at $T = 300K$, the $Ag/Au(100)$ system
does not exhibit true second-order phase transitions but rather a crossover
behavior between states. A diagram showing the location of the ordered and
disordered states in the $\mu$ versus $\tau$ plane is obtained and discussed.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:21:24 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Gimenez",
"M. Cecilia",
""
],
[
"Albano",
"Ezequiel V.",
""
]
] |
0705.4471 | Hong Lu | W. Chen and H. Lu | Kerr-Schild Structure and Harmonic 2-forms on (A)dS-Kerr-NUT Metrics | Latex, 11 pages, references added | Phys.Lett.B658:158-163,2008 | 10.1016/j.physletb.2007.09.066 | MIFP-07-15 | hep-th gr-qc | null | We demonstrate that the general (A)dS-Kerr-NUT solutions in D dimensions with
([D/2], [(D+1)/2]) signature admit [D/2] linearly-independent,
mutually-orthogonal and affinely-parameterised null geodesic congruences. This
enables us to write the metrics in a multi-Kerr-Schild form, where the mass and
all of the NUT parameters enter the metrics linearly. In the case of D=2n, we
also obtain n harmonic 2-forms, which can be viewed as charged (A)dS-Kerr-NUT
solution at the linear level of small-charge expansion, for the
higher-dimensional Einstein-Maxwell theories. In the BPS limit, these 2-forms
reduce to n-1 linearly-independent ones, whilst the resulting Calabi-Yau metric
acquires a Kahler 2-form, leaving the total number the same.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 19:49:15 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Jun 2007 19:20:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chen",
"W.",
""
],
[
"Lu",
"H.",
""
]
] |
0705.4472 | Gabriele Ghisellini | Gabriele Ghisellini (Oss. Astr. di Brera, Italy) | Cosmological implications of Gamma Ray Bursts | 8 pages, 4 figures, invited talk at the meeting of the Italian
Astron. Society | null | null | null | astro-ph | null | The discovery that the bolometric energetics (and/or peak luminosity) of
Gamma Ray Bursts correlates with their spectral properties has allowed to
standardize the burst energetics to such a degree to enable their use for
constraining the cosmological parameters, in the same way as SN Ia. With
respect to SN Ia, there is the advantage of having sources free from extinction
problems, and easily detectable also at large redshifts. On the other hand,
these spectral-energy correlations are not yet understood, and bursts with a
complete set of information (to standardize their energetics) are still few
(two dozens). There have been already attempts to use these bursts to constrain
Omega_Lambda and Omega_M, and even the dark energy equation of state. These
results are very encouraging.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:32:54 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Ghisellini",
"Gabriele",
"",
"Oss. Astr. di Brera, Italy"
]
] |
0705.4473 | Adrian Baule | A. Baule, R. Friedrich | Two-point correlation function of the fractional Ornstein-Uhlenbeck
process | 6 pages, 2 figures; Journal's website can be found at
http://www.epljournal.org | Europhysics Letters 79 (2007) 60004 | 10.1209/0295-5075/79/60004 | null | cond-mat.stat-mech cond-mat.soft | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We calculate the two-point correlation function <x(t2)x(t1)> for a
subdiffusive continuous time random walk in a parabolic potential, generalizing
well-known results for the single-time statistics to two times. A closed
analytical expression is found for initial equilibrium, revealing a clear
deviation from a Mittag-Leffler decay.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:46:55 GMT"
},
{
"version": "v2",
"created": "Thu, 31 Jul 2008 16:45:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Baule",
"A.",
""
],
[
"Friedrich",
"R.",
""
]
] |
0705.4474 | M. Leticia Rubio Puzzo PhD | M. Leticia Rubio Puzzo and Ezequiel V. Albano | Study of Damage Propagation at the Interface Localization-Delocalization
Transition of the Confined Ising Model | 22 pages, 13 figures included | Phys. Rev. B, 66, 104409 (1-9), 2002 | 10.1103/PhysRevB.66.104409 | null | cond-mat.stat-mech | null | The propagation of damage in a confined magnetic Ising film, with short range
competing magnetic fields ($h$) acting at opposite walls, is studied by means
of Monte Carlo simulations. Due to the presence of the fields, the film
undergoes a wetting transition at a well defined critical temperature $T_w(h)$.
In fact, the competing fields causes the occurrence of an interface between
magnetic domains of different orientation. For $T < T_w(h)$ ($T > T_w(h)$) such
interface is bounded (unbounded) to the walls, while right at $T_w(h)$ the
interface is essentially located at the center of the film.
It is found that the spatio-temporal spreading of the damage becomes
considerably enhanced by the presence of the interface, which act as a
''catalyst'' of the damage causing an enhancement of the total damaged area.
The critical points for damage spreading are evaluated by extrapolation to the
thermodynamic limit using a finite-size scaling approach. Furthermore, the
wetting transition effectively shifts the location of the damage spreading
critical points, as compared with the well known critical temperature of the
order-disorder transition characteristic of the Ising model. Such a critical
points are found to be placed within the non-wet phase.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:38:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Puzzo",
"M. Leticia Rubio",
""
],
[
"Albano",
"Ezequiel V.",
""
]
] |
0705.4475 | Marco Mazza | Marco G. Mazza, Nicolas Giovambattista, H.Eugene Stanley, Francis W.
Starr | Dynamical heterogeneities and the breakdown of the Stokes-Einstein and
Stokes-Einstein-Debye relations in simulated water | null | null | null | null | cond-mat.stat-mech cond-mat.soft | null | We study the Stokes-Einstein (SE) and the Stokes-Einstein-Debye (SED)
relations using molecular dynamics simulations of the extended simple point
charge model of water. We find that both the SE and SED relations break down at
low temperature. To explore the relationship between these breakdowns and
dynamical heterogeneities (DH), we also calculate the SE and SED relations for
subsets of the 7% ``fastest'' and 7% ``slowest'' molecules. We find that the SE
and SED relations break down in both subsets, and that the breakdowns occur on
all scales of mobility. Thus these breakdowns appear to be generalized
phenomena, in contrast with the view where only the most mobile molecules are
the origin of the breakdown of the SE and SED relations, embedded in an
inactive background where these relations hold. At low temperature, the SE and
SED relations in both subsets of molecules are replaced with ``fractional'' SE
and SED relations, $D_t\sim(\tau/T)^{-\xi_t}$ and $D_r\sim(\tau/T)^{-\xi_r}$
where $\xi_t\approx0.84<1$ and $\xi_r\approx0.75<1$. We also find that there is
a decoupling between rotational and translational motion, and that this
decoupling occurs in both fastest and slowest subsets of molecules. We also
find that when the decoupling increases, upon cooling, the probability of a
molecule being classified as both translationally and rotationally fastest also
increases. To study the effect of time scale for SE and SED breakdown and
decoupling, we introduce a time-dependent version of the SE and SED relations,
and a time-dependent function that measures the extent of decoupling. Our
results suggest that both the decoupling and SE and SED breakdowns are
originated at the time scale corresponding to the end of the cage regime, when
diffusion starts. This is also the time scale when the DH are more relevant.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:45:59 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Mazza",
"Marco G.",
""
],
[
"Giovambattista",
"Nicolas",
""
],
[
"Stanley",
"H. Eugene",
""
],
[
"Starr",
"Francis W.",
""
]
] |
0705.4476 | Aiyou Chen | Aiyou Chen, Jin Cao | Network tomography based on 1-D projections | Published at http://dx.doi.org/10.1214/074921707000000238 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 45-61 | 10.1214/074921707000000238 | IMS-LNMS54-LNMS5404 | stat.AP math.ST stat.ME stat.TH | null | Network tomography has been regarded as one of the most promising
methodologies for performance evaluation and diagnosis of the massive and
decentralized Internet. This paper proposes a new estimation approach for
solving a class of inverse problems in network tomography, based on marginal
distributions of a sequence of one-dimensional linear projections of the
observed data. We give a general identifiability result for the proposed method
and study the design issue of these one dimensional projections in terms of
statistical efficiency. We show that for a simple Gaussian tomography model,
there is an optimal set of one-dimensional projections such that the estimator
obtained from these projections is asymptotically as efficient as the maximum
likelihood estimator based on the joint distribution of the observed data. For
practical applications, we carry out simulation studies of the proposed method
for two instances of network tomography. The first is for traffic demand
tomography using a Gaussian Origin-Destination traffic model with a power
relation between its mean and variance, and the second is for network delay
tomography where the link delays are to be estimated from the end-to-end path
delays. We compare estimators obtained from our method and that obtained from
using the joint distribution and other lower dimensional projections, and show
that in both cases, the proposed method yields satisfactory results.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 20:52:27 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 07:08:12 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Chen",
"Aiyou",
""
],
[
"Cao",
"Jin",
""
]
] |
0705.4477 | Gustavo Yepes | Yehuda Hoffman (Hebrew U.), Ofer Lahav (UCL), Gustavo Yepes (UAM) and
Yaniv Dover (Hebrew U.) | The Future of the Local Large Scale Structure: the roles of Dark Matter
and Dark Energy | 14 pages and 4 figures. New version, accepted for publication in JCAP | JCAP0710:016,2007 | 10.1088/1475-7516/2007/10/016 | null | astro-ph | null | We study the distinct effects of Dark Matter and Dark Energy on the future
evolution of nearby large scale structures using constrained N-body
simulations. We contrast a model of Cold Dark Matter and a Cosmological
Constant (LCDM) with an Open CDM (OCDM) model with the same matter density
Omega_m =0.3 and the same Hubble constant h=0.7. Already by the time the scale
factor increased by a factor of 6 (29 Gyr from now in LCDM; 78 Gyr from now in
OCDM) the comoving position of the Local Group is frozen. Well before that
epoch the two most massive members of the Local Group, the Milky Way and
Andromeda, will merge. However, as the expansion rates of the scale factor in
the two models are different, the Local Group will be receding in physical
coordinates from Virgo exponentially in a LCDM model and at a roughly constant
velocity in an OCDM model. More generally, in comoving coordinates the future
large scale structure will look like a sharpened image of the present
structure: the skeleton of the cosmic web will remain the same, but clusters
will be more `isolated' and the filaments will become thinner. This implies
that the long-term fate of large scale structure as seen in comoving
coordinates is determined primarily by the matter density. We conclude that
although the LCDM model is accelerating at present due to its Dark Energy
component while the OCDM model is non accelerating, their large scale structure
in the future will look very similar in comoving coordinates.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 21:42:59 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 09:36:12 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hoffman",
"Yehuda",
"",
"Hebrew U."
],
[
"Lahav",
"Ofer",
"",
"UCL"
],
[
"Yepes",
"Gustavo",
"",
"UAM"
],
[
"Dover",
"Yaniv",
"",
"Hebrew U."
]
] |
0705.4478 | Guillaume Pignol | V. V. Nesvizhevsky, G. Pignol, K. V. Protasov | Experimental constraints for additional short-range forces from neutron
experiments | presented in "les rencontres de Moriond" 2007 conference | null | null | null | nucl-ex | null | We present preliminary results on sensitivity of experiments with slow
neutrons to constrain additional forces in a wide distance range: from
picometers to micrometers. In the sub-nanometer range, available data on
lengths of neutron scattering at nuclei provide the most competitive
constraint. We show that it can be improved significantly in a dedicated
measurement of asymmetry of neutron scattering at noble gases. In the
micrometer range, we present sensitivity of the future GRANIT experiment.
Further analysis will be presented in following publications.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 21:44:00 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Nesvizhevsky",
"V. V.",
""
],
[
"Pignol",
"G.",
""
],
[
"Protasov",
"K. V.",
""
]
] |
0705.4479 | Natan Andrei | Pankaj Mehta and Natan Andrei | Nonequilibrium quantum-impurities: from entropy production to
information theory | 5 pages, 1 figure new version with minor clarifications | null | 10.1103/PhysRevLett.100.086804 | null | cond-mat.str-el cond-mat.stat-mech | null | Nonequilibrium steady-state currents, unlike their equilibrium counterparts,
continuously dissipate energy into their physical surroundings leading to
entropy production and time-reversal symmetry breaking. This letter discusses
these issues in the context of quantum impurity models driven out of
equilibrium by attaching the impurity to leads at different chemical potentials
and temperatures. We start by pointing out that entropy production is often
hidden in traditional treatments of quantum-impurity models. We then use simple
thermodynamic arguments to define the rate of entropy production. Using the
scattering framework recently developed by the authors we show that the rate of
entropy production has a simple information theoretic interpretation in terms
of the Shannon entropy and Kullback-Leibler divergence of nonequilibrium
distribution function. This allows us to show that the entropy production is
strictly positive for any nonequilibrium steady-state. We conclude by applying
these ideas to the Resonance Level Model and the Kondo model.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 19:20:26 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jun 2007 15:46:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mehta",
"Pankaj",
""
],
[
"Andrei",
"Natan",
""
]
] |
0705.4480 | Andrew Steffl | A.J. Steffl, P.A. Delamere, F. Bagenal | Cassini UVIS Observations of the Io Plasma Torus. IV. Modeling Temporal
and Azimuthal Variability | Revised 24 August 2007 Accepted by Icarus, 50 pages, 2 Tables, 8
figures | Icarus 194:153-165,2008 | 10.1016/j.icarus.2007.09.019 | null | astro-ph | null | In this fourth paper in a series, we present a model of the remarkable
temporal and azimuthal variability of the Io plasma torus observed during the
Cassini encounter with Jupiter. Over a period of three months, the Cassini
Ultraviolet Imaging Spectrograph (UVIS) observed a dramatic variation in the
average torus composition. Superimposed on this long-term variation, is a
10.07-hour periodicity caused by an azimuthal variation in plasma composition
subcorotating relative to System III longitude. Quite surprisingly, the
amplitude of the azimuthal variation appears to be modulated at the beat
frequency between the System III period and the observed 10.07-hour period.
Previously, we have successfully modeled the months-long compositional change
by supposing a factor of three increase in the amount of material supplied to
Io's extended neutral clouds. Here, we extend our torus chemistry model to
include an azimuthal dimension. We postulate the existence of two azimuthal
variations in the number of super-thermal electrons in the torus: a primary
variation that subcorotates with a period of 10.07 hours and a secondary
variation that remains fixed in System III longitude. Using these two hot
electron variations, our model can reproduce the observed temporal and
azimuthal variations observed by Cassini UVIS.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 21:51:23 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 18:06:44 GMT"
}
] | 2009-10-16T00:00:00 | [
[
"Steffl",
"A. J.",
""
],
[
"Delamere",
"P. A.",
""
],
[
"Bagenal",
"F.",
""
]
] |
0705.4481 | Davis Doherty | Davis C. Doherty | Singularities of generic projection hypersurfaces | 9 pages; Proof of Theorem 4.2 updated; Corollary 4.4 clarified | null | null | null | math.AG | null | Linearly projecting smooth projective varieties provides a method of
obtaining hypersurfaces birational to the original varieties. We show that in
low dimension, the resulting hypersurfaces only have Du Bois singularities.
Moreover, we conclude that these Du Bois singularities are in fact semi log
canonical. However, we demonstrate the existence of counterexamples in high
dimension -- the generic linear projection of certain varieties of dimension 30
or higher is neither semi log canonical nor Du Bois.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 21:59:16 GMT"
},
{
"version": "v2",
"created": "Sun, 10 Jun 2007 18:38:54 GMT"
}
] | 2007-06-10T00:00:00 | [
[
"Doherty",
"Davis C.",
""
]
] |
0705.4482 | Alexander V. Savin | Alexander V. Savin and Yuri S. Kivshar | Discrete Nonlinear Breathing Modes in Carbon Nanotubes | 4 pages, 5 figures | null | null | null | nlin.PS | null | We study large-amplitude oscillations of carbon nanotubes with chiralities
$(m,0)$ and $(m,m)$ and predict the existence of localized nonlinear modes in
the form of {\em discrete breathers}. In nanotubes with the index $(m,0)$ {\em
three types} of localized modes can exist, namely longitudinal, radial, and
twisting breathers; however only the twisting breathers, or {\em twistons}, are
nonradiating nonlinear modes which exist in the frequency gaps of the linear
spectrum. Geometry of carbon nanotubes with the index $(m,m)$ allows only the
existence of broad radial breathers in a narrow spectral range.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 22:04:23 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Savin",
"Alexander V.",
""
],
[
"Kivshar",
"Yuri S.",
""
]
] |
0705.4483 | Bjarke Hammersholt Roune | Bjarke Hammersholt Roune | The Label Algorithm For Irreducible Decomposition of Monomial Ideals | null | null | null | null | math.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The paper that was here is a preprint that was never turned into a proper
paper. In particular it does not have enough citations to the literature. The
paper "The Slice Algorithm For Irreducible Decomposition of Monomial Ideals"
contains a much better description of the Label algorithm than this preprint
did. If you still wish to read the original preprint then access the arXiv's
version 1 of this paper, instead of version 2 which is what you are reading
now.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 22:45:50 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Nov 2009 14:55:15 GMT"
}
] | 2009-11-11T00:00:00 | [
[
"Roune",
"Bjarke Hammersholt",
""
]
] |
0705.4484 | Ashish Saxena | Stefano Giusto, Ashish Saxena | Stationary axisymmetric solutions of five dimensional gravity | 31 pages, LaTeX; references added | Class.Quant.Grav.24:4269-4294,2007 | 10.1088/0264-9381/24/17/002 | null | hep-th gr-qc | null | We consider stationary axisymmetric solutions of general relativity that
asymptote to five dimensional Minkowski space. It is known that this system has
a hidden SL(3,R) symmetry. We identify an SO(2,1) subgroup of this symmetry
group that preserves the asymptotic boundary conditions. We show that the
action of this subgroup on a static solution generates a one-parameter family
of stationary solutions carrying angular momentum. We conjecture that by
repeated applications of this procedure one can generate all stationary
axisymmetric solutions starting from static ones. As an example, we derive the
Myers-Perry black hole starting from the Schwarzschild solution in five
dimensions.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 23:08:28 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Jun 2007 15:53:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Giusto",
"Stefano",
""
],
[
"Saxena",
"Ashish",
""
]
] |
0705.4485 | Edoardo Airoldi | Edoardo M Airoldi, David M Blei, Stephen E Fienberg, Eric P Xing | Mixed membership stochastic blockmodels | 46 pages, 14 figures, 3 tables | Journal of Machine Learning Research, 9, 1981-2014. | null | null | stat.ME cs.LG math.ST physics.soc-ph stat.ML stat.TH | null | Observations consisting of measurements on relationships for pairs of objects
arise in many settings, such as protein interaction and gene regulatory
networks, collections of author-recipient email, and social networks. Analyzing
such data with probabilisic models can be delicate because the simple
exchangeability assumptions underlying many boilerplate models no longer hold.
In this paper, we describe a latent variable model of such data called the
mixed membership stochastic blockmodel. This model extends blockmodels for
relational data to ones which capture mixed membership latent relational
structure, thus providing an object-specific low-dimensional representation. We
develop a general variational inference algorithm for fast approximate
posterior inference. We explore applications to social and protein interaction
networks.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 23:22:59 GMT"
}
] | 2010-02-22T00:00:00 | [
[
"Airoldi",
"Edoardo M",
""
],
[
"Blei",
"David M",
""
],
[
"Fienberg",
"Stephen E",
""
],
[
"Xing",
"Eric P",
""
]
] |
0705.4486 | Tigran Sedrakyan | T. A. Sedrakyan, M. E. Raikh | Crossover from weak localization to Shubnikov-de Haas oscillations in a
high mobility 2D electron gas | 4+ pages, 3 figures | Phys. Rev. Lett. 100, 106806 (2008) | 10.1103/PhysRevLett.100.106806 | null | cond-mat.mes-hall | null | We study the magnetoresistance, \delta\rho_{xx}(B)/\rho_0, of a high-mobility
2D electron gas in the domain of magnetic fields, B, intermediate between the
weak localization and the Shubnikov-de Haas oscillations, where
\delta\rho_{xx}(B)/\rho_0 is governed by the interaction effects. Assuming
short-range impurity scattering, we demonstrate that in the {\em second order}
in the interaction parameter, $\lambda$, a {\em linear} B-dependence,
\delta\rho_{xx}(B)/\rho_0\sim \lambda^2\omega_c/E_F with {\em
temperature-independent} slope emerges in this domain of B (here \omega_c and
E_F are the cyclotron frequency and the Fermi energy, respectively). Unlike
previous mechanisms, the linear magnetoresistance is {\em unrelated} to the
electron executing the full Larmour circle, but rather originates from the
impurity scattering via the B-dependence of the {\em phase} of the
impurity-induced Friedel oscillations.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 00:50:21 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Mar 2008 05:35:19 GMT"
}
] | 2008-03-17T00:00:00 | [
[
"Sedrakyan",
"T. A.",
""
],
[
"Raikh",
"M. E.",
""
]
] |
0705.4487 | Gordan Zitkovic | Gordan Zitkovic | Utility Maximization with a Stochastic Clock and an Unbounded Random
Endowment | null | Ann. Appl. Prob (2005), vol. 15, no. 1B, pp. 748-777 | null | null | q-fin.GN math.OC math.PR | null | We introduce a linear space of finitely additive measures to treat the
problem of optimal expected utility from consumption under a stochastic clock
and an unbounded random endowment process. In this way we establish existence
and uniqueness for a large class of utility maximization problems including the
classical ones of terminal wealth or consumption, as well as the problems
depending on a random time-horizon or multiple consumption instances. As an
example we treat explicitly the problem of maximizing the logarithmic utility
of a consumption stream, where the local time of an Ornstein-Uhlenbeck process
acts as a stochastic clock.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 23:39:54 GMT"
}
] | 2008-12-10T00:00:00 | [
[
"Zitkovic",
"Gordan",
""
]
] |
0705.4488 | Lutz Duembgen | Lutz Duembgen, Christoph Leuenberger | Explicit bounds for the approximation error in Benford's law | 16 pages, one figure | Electronic Communications in Probability 13 (2008), 99-112 | null | null | math.PR | null | Benford's law states that for many random variables X > 0 its leading digit D
= D(X) satisfies approximately the equation P(D = d) = log_{10}(1 + 1/d) for d
= 1,2,...,9. This phenomenon follows from another, maybe more intuitive fact,
applied to Y := log_{10}(X): For many real random variables Y, the remainder U
:= Y - floor(Y) is approximately uniformly distributed on [0,1). The present
paper provides new explicit bounds for the latter approximation in terms of the
total variation of the density of Y or some derivative of it. These bounds are
an interesting alternative to traditional Fourier methods which yield mostly
qualitative results. As a by-product we obtain explicit bounds for the
approximation error in Benford's law.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 23:53:48 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 14:39:12 GMT"
},
{
"version": "v3",
"created": "Wed, 2 Jan 2008 08:40:26 GMT"
}
] | 2008-06-25T00:00:00 | [
[
"Duembgen",
"Lutz",
""
],
[
"Leuenberger",
"Christoph",
""
]
] |
0705.4489 | Weiqiang Yu | W. Yu, J. S. Higgins, P. Bach, R. L. Greene | Coexistence of Antiferromagnetism and Superconductivity in
Electron-doped High-Tc Superconductors | null | Phys. Rev. B 76, 020503 (2007) | 10.1103/PhysRevB.76.020503 | null | cond-mat.supr-con cond-mat.str-el | null | We present magnetotransport evidence for antiferromagnetism in films of the
electron-doped cuprates Pr$_{2-x}$Ce$_x$CuO$_4$. Our results show clear
signature of static antiferromagnetism up to optimal doping x=0.15, with a
quantum phase transition close to x=0.16, and a coexistence of static
antiferromagnetism and superconductivity for 0.12$\le$x$\le$0.15.
| [
{
"version": "v1",
"created": "Wed, 30 May 2007 23:42:04 GMT"
}
] | 2007-09-26T00:00:00 | [
[
"Yu",
"W.",
""
],
[
"Higgins",
"J. S.",
""
],
[
"Bach",
"P.",
""
],
[
"Greene",
"R. L.",
""
]
] |
0705.4490 | Hemachander Subramanian | Hemachander Subramanian and J. E. Han | Geometry-induced frustration of magnetization in a planar soft-hard
magnetic system | 4 pages, 5 figures | null | null | null | cond-mat.other | null | We computationally study the frustrated magnetic configurations of a thin
soft magnetic layer with the boundary condition fixed by underlying hard
magnets. Driven by geometrical constraints and external magnetic field,
transitions between frustrated energy minima result in magnetic hysteretic
behavior. The presence of soft-magnet introduces strong undulations in the
energy landscape in a length scale set by the magnetic property of the soft
magnet. We propose a possible use of the phenomena to locally control the
movement of magnetic nanoparticles.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 00:48:09 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Subramanian",
"Hemachander",
""
],
[
"Han",
"J. E.",
""
]
] |
0705.4491 | Dave Besson | I. Kravchenko, et al | Event Reconstruction and Data Acquisition for the RICE Experiment at the
South Pole | null | null | null | null | astro-ph | null | The RICE experiment seeks to measure ultra-high energy neutrinos (E(nu)>10
PeV) by detection of the radio wavelength Cherenkov radiation produced by
neutrino-ice collisions within Antarctic ice. An array of 16 dipole antennas,
buried at depths of 100-400 m, and sensitive over the 100-500 MHz frequency
range, has been continuously taking data for the last seven years. We herein
describe the design and performance of the RICE experiment's event trigger and
data acquisition system, highlighting elements not covered as extensively in
previous publications.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 01:36:49 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Kravchenko",
"I.",
""
]
] |
0705.4492 | Jonathan E. Grindlay | Jonathan E. Grindlay and the EXIST Team | Jets, Blazars and the EBL in the GLAST-EXIST Era | 3 pages, 2 Figs., to appear in Proc. First GLAST Symp. (Stanford,
Feb. 5-8, 2007), eds. S.Ritz, P.F.Michelson, and C.Meegan, AIP Conf. Proc | AIPConf.Proc.921:211-216,2007 | 10.1063/1.2757303 | null | astro-ph | null | The synergy of GLAST and the proposed EXIST mission as the Black Hole Finder
Probe in the Beyond Einstein Program is remarkable. With its full-sky per orbit
hard X-ray imaging (3-600 keV) and "nuFnu" sensitivity comparable to GLAST,
EXIST could measure variability and spectra of Blazars in the hard X-ray
synchrotron component simultaneous with GLAST (~10-100GeV) measures of the
inverse Compton component, thereby uniquely constraining intrinsic source
spectra and allowing measured high energy spectral breaks to measure the cosmic
diffuse extra-galactic background light (EBL) by determining the intervening
diffuse IR photon field required to yield the observed break from photon-photon
absorption. Such studies also constrain the physics of jets (and parameters and
indeed the validity of SSC models) and the origin of the >100 MeV gamma-ray
diffuse background likely arising from Blazars and jet-dominated sources. An
overview of the EXIST mission, which could fly in the GLAST era, is given
together with a synopsis of other key synergies of GLAST-EXIST science.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 00:56:47 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Grindlay",
"Jonathan E.",
""
],
[
"Team",
"the EXIST",
""
]
] |
0705.4493 | Francesco D'Eramo | Francesco D'Eramo (Scuola Normale Superiore) | Dark matter and Higgs boson physics | 17 pages, 7 figures. v3: published version (small corrections) | Phys.Rev.D76:083522,2007 | 10.1103/PhysRevD.76.083522 | null | hep-ph | null | A vector-like colorless fermion doublet and a singlet added to the Standard
Model allow a consistent interpretation of dark matter in terms of the lightest
neutral particle, as they may help in obtaining successful gauge coupling
unification. We analyze in detail the mass range of the lightest neutral
particle below the W mass, i.e. in a range of the parameters where the physics
of the Standard Model Higgs boson may be substantially affected either directly
or indirectly.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 01:21:29 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 13:07:55 GMT"
},
{
"version": "v3",
"created": "Thu, 25 Oct 2007 21:42:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"D'Eramo",
"Francesco",
"",
"Scuola Normale Superiore"
]
] |
0705.4494 | Greg Stinson | G. S. Stinson, J. J. Dalcanton, T. Quinn, T. Kaufmann, and J. Wadsley | Breathing in Low Mass Galaxies: A Study of Episodic Star Formation | 5 pages, 3 figures, accepted ApJ. Full resolution figures and movies
available at http://hpcc.astro.washington.edu/feedback | Astrophys.J.667:170-175,2007 | 10.1086/520504 | null | astro-ph | null | We simulate the collapse of isolated dwarf galaxies using SPH + N-Body
simulations including a physically motivated description of the effects of
supernova feedback. As the gas collapses and stars form, the supernova feedback
disrupts enough gas to temporarily quench star formation. The gas flows outward
into a hot halo, where it cools until star formation can continue once more and
the cycle repeats. The star formation histories of isolated Local Group dwarf
galaxies exhibit similar episodic bursts of star formation. We examine the mass
dependence of the stellar velocity dispersions and find that they are no less
than half the velocity of the halos measured at the virial radius.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 01:03:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stinson",
"G. S.",
""
],
[
"Dalcanton",
"J. J.",
""
],
[
"Quinn",
"T.",
""
],
[
"Kaufmann",
"T.",
""
],
[
"Wadsley",
"J.",
""
]
] |
0705.4495 | Mikhail Smolyakov | Mikhail N. Smolyakov, Igor P. Volobuev | Single-brane world with stabilized extra dimension | 14 pages, 4 figures, minor corrections to match published version | Int.J.Mod.Phys.A23:761-775,2008 | 10.1142/S0217751X08038196 | null | hep-th hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a model describing a single brane with tension embedded into a
five-dimensional space-time with compact extra dimension, which can be easily
stabilized. We examine the linearized gravity in the model and obtain an
expression for the four-dimensional Planck mass on the brane in terms of the
model parameters. It is also shown that the scalar sector of the effective
four-dimensional theory contain a tachyonic mode, and we discuss the problem of
stability of the model.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 19:05:40 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Nov 2008 16:16:15 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Smolyakov",
"Mikhail N.",
""
],
[
"Volobuev",
"Igor P.",
""
]
] |
0705.4496 | Dilian Yang | Kenneth R. Davidson, Stephen C. Power, Dilian Yang | Dilation Theory for Rank 2 Graph Algebras | 29 pages, 5 figures | null | null | null | math.OA | null | An analysis is given of $*$-representations of rank 2 single vertex graphs.
We develop dilation theory for the non-selfadjoint algebras $\A_\theta$ and
$\A_u$ which are associated with the commutation relation permutation $\theta$
of a 2 graph and, more generally, with commutation relations determined by a
unitary matrix $u$ in $M_m(\bC) \otimes M_n(\bC)$. We show that a defect free
row contractive representation has a unique minimal dilation to a
$*$-representation and we provide a new simpler proof of Solel's row isometric
dilation of two $u$-commuting row contractions. Furthermore it is shown that
the C*-envelope of $\A_u$ is the generalised Cuntz algebra $\O_{X_u}$ for the
product system $X_u$ of $u$; that for $m\geq 2 $ and $n \geq 2 $ contractive
representations of $\Ath$ need not be completely contractive; and that the
universal tensor algebra $\T_+(X_u)$ need not be isometrically isomorphic to
$\A_u$.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 01:10:45 GMT"
}
] | 2007-06-01T00:00:00 | [
[
"Davidson",
"Kenneth R.",
""
],
[
"Power",
"Stephen C.",
""
],
[
"Yang",
"Dilian",
""
]
] |
0705.4497 | Neil Bushong | Neil Bushong, Yuriy Pershin, and Massimiliano Di Ventra | Turbulence-induced magnetic flux asymmetry at nanoscale junctions | 4 pages, 4 figures | Phys. Rev. Lett. 99, 226802 (2007) | 10.1103/PhysRevLett.99.226802 | null | cond-mat.other | null | It was recently predicted [J. Phys.: Condens. Matter 18, 11059 (2006)] that
turbulence of the electron flow may develop at nonadiabatic nanoscale junctions
under appropriate conditions. Here we show that such an effect leads to an
asymmetric current-induced magnetic field on the two sides of an otherwise
symmetric junction. We propose that by measuring the fluxes ensuing from these
fields across two surfaces placed at the two sides of the junction would
provide direct and noninvasive evidence of the transition from laminar to
turbulent electron flow. The flux asymmetry is predicted to first increase,
reach a maximum and then decrease with increasing current, i.e. with increasing
amount of turbulence.
| [
{
"version": "v1",
"created": "Thu, 31 May 2007 01:17:25 GMT"
},
{
"version": "v2",
"created": "Fri, 1 Jun 2007 17:46:34 GMT"
}
] | 2008-03-24T00:00:00 | [
[
"Bushong",
"Neil",
""
],
[
"Pershin",
"Yuriy",
""
],
[
"Di Ventra",
"Massimiliano",
""
]
] |
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