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sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.3730 | Pavlos Xenitidis | A. Tongas, D. Tsoubelis and P. Xenitidis | Affine linear and D4 symmetric lattice equations : symmetry analysis and
reductions | 31 pages | null | 10.1088/1751-8113/40/44/015 | null | nlin.SI | null | We consider lattice equations on ${\mathds{Z}}^2$ which are autonomous,
affine linear and possess the symmetries of the square. Some basic properties
of equations of this type are derived, as well as a sufficient linearization
condition and a conservation law. A systematic analysis of the Lie point and
the generalized three- and five-point symmetries is presented. It leads to the
generic form of the symmetry generators of all the equations in this class,
which satisfy a certain non-degeneracy condition. Finally, symmetry reductions
of certain lattice equations to discrete analogues of the Painlev\'e equations
are considered.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:21:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tongas",
"A.",
""
],
[
"Tsoubelis",
"D.",
""
],
[
"Xenitidis",
"P.",
""
]
] |
0707.3731 | Tomas Dohnal | Tomas Dohnal, Dmitry Pelinovsky, and Guido Schneider | Coupled-mode equations and gap solitons in a two-dimensional nonlinear
elliptic problem with a separable periodic potential | 32 pages, 16 figures | null | 10.1007/s00332-008-9027-9 | null | math.AP nlin.PS physics.optics | null | We address a two-dimensional nonlinear elliptic problem with a
finite-amplitude periodic potential. For a class of separable symmetric
potentials, we study the bifurcation of the first band gap in the spectrum of
the linear Schr\"{o}dinger operator and the relevant coupled-mode equations to
describe this bifurcation. The coupled-mode equations are derived by the
rigorous analysis based on the Fourier--Bloch decomposition and the Implicit
Function Theorem in the space of bounded continuous functions vanishing at
infinity. Persistence of reversible localized solutions, called gap solitons,
beyond the coupled-mode equations is proved under a non-degeneracy assumption
on the kernel of the linearization operator. Various branches of reversible
localized solutions are classified numerically in the framework of the
coupled-mode equations and convergence of the approximation error is verified.
Error estimates on the time-dependent solutions of the Gross--Pitaevskii
equation and the coupled-mode equations are obtained for a finite-time
interval.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:04:42 GMT"
},
{
"version": "v2",
"created": "Wed, 9 Apr 2008 15:01:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dohnal",
"Tomas",
""
],
[
"Pelinovsky",
"Dmitry",
""
],
[
"Schneider",
"Guido",
""
]
] |
0707.3732 | Jean-Luc Beuchat | Jean-Luc Beuchat | Further Comments on "Residue-to-Binary Converters Based on New Chinese
Remainder Theorems" | null | null | null | null | cs.OH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Ananda Mohan suggested that the first New Chinese Remainder Theorem
introduced by Wang can be derived from the constructive proof of the well-known
Chinese Remainder Theorem (CRT) and claimed that Wang's approach is the same as
the one proposed earlier by Huang. Ananda Mohan's proof is however erroneous
and we show here that Wang's New CRT I is a rewriting of an algorithm
previously sketched by Hitz and Kaltofen.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:08:50 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Mar 2009 04:24:57 GMT"
}
] | 2009-03-23T00:00:00 | [
[
"Beuchat",
"Jean-Luc",
""
]
] |
0707.3733 | Charlotte Gils | Charlotte Gils, Helmut G. Katzgraber, Matthias Troyer | Absence of a structural glass phase in a monoatomic model liquid
predicted to undergo an ideal glass transition | 4 pages, 4 figures, minor changes in introduction and conclusions,
additional references | J. Stat. Mech. (2007) P09011 | 10.1088/1742-5468/2007/09/P09011 | null | cond-mat.dis-nn | null | We study numerically a monodisperse model of interacting classical particles
predicted to exhibit a static liquid-glass transition. Using a dynamical Monte
Carlo method we show that the model does not freeze into a glassy phase at low
temperatures. Instead, depending on the choice of the hard-core radius for the
particles the system either collapses trivially or a polycrystalline hexagonal
structure emerges.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:11:34 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Sep 2007 18:16:01 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Gils",
"Charlotte",
""
],
[
"Katzgraber",
"Helmut G.",
""
],
[
"Troyer",
"Matthias",
""
]
] |
0707.3734 | Jean-Fran\c{c}ois Renaud | Jean-Fran\c{c}ois Renaud and Bruno R\'emillard | Malliavin calculus and Clark-Ocone formula for functionals of a
square-integrable L\'evy process | 30 pages | null | null | null | math.PR | null | In this paper, we construct a Malliavin derivative for functionals of
square-integrable L\'evy processes and derive a Clark-Ocone formula. The
Malliavin derivative is defined via chaos expansions involving stochastic
integrals with respect to Brownian motion and Poisson random measure. As an
illustration, we compute the explicit martingale representation for the maximum
of a L\'evy process.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:13:39 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Renaud",
"Jean-François",
""
],
[
"Rémillard",
"Bruno",
""
]
] |
0707.3735 | Markus Rauscher | S. Mechkov, G. Oshanin, M. Rauscher, M. Brinkmann, A. M. Cazabat, S.
Dietrich | Contact line stability of ridges and drops | 6 pages, 1 figure | null | 10.1209/0295-5075/80/66002 | null | cond-mat.soft | null | Within the framework of a semi-microscopic interface displacement model we
analyze the linear stability of sessile ridges and drops of a non-volatile
liquid on a homogeneous, partially wet substrate, for both signs and arbitrary
amplitudes of the three-phase contact line tension. Focusing on perturbations
which correspond to deformations of the three-phase contact line, we find that
drops are generally stable while ridges are subject only to the long-wavelength
Rayleigh-Plateau instability leading to a breakup into droplets, in contrast to
the predictions of capillary models which take line tension into account. We
argue that the short-wavelength instabilities predicted within the framework of
the latter macroscopic capillary theory occur outside its range of validity and
thus are spurious.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:17:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mechkov",
"S.",
""
],
[
"Oshanin",
"G.",
""
],
[
"Rauscher",
"M.",
""
],
[
"Brinkmann",
"M.",
""
],
[
"Cazabat",
"A. M.",
""
],
[
"Dietrich",
"S.",
""
]
] |
0707.3736 | Zhi-Gang Wang | Zhi-Gang Wang | Strong decay $\Delta^{++} \to p\pi$ with light-cone QCD sum rules | 15 pages, 2 figures, 7-version | Eur.Phys.J.C57:711-718,2008 | 10.1140/epjc/s10052-008-0699-y | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this article, we calculate the strong coupling constant $g_{\Delta N\pi}$
and study the strong decay $\Delta^{++} \to p\pi$ with the light-cone QCD sum
rules. The numerical value of the strong coupling constant $g_{\Delta N\pi}$ is
consistent with the experimental data. The small discrepancy maybe due to
failure to take into account the perturbative $\mathcal {O}(\alpha_s)$
corrections.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:17:21 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 15:28:25 GMT"
},
{
"version": "v3",
"created": "Fri, 19 Oct 2007 12:58:24 GMT"
},
{
"version": "v4",
"created": "Thu, 1 May 2008 02:09:20 GMT"
},
{
"version": "v5",
"created": "Thu, 29 May 2008 03:40:41 GMT"
},
{
"version": "v6",
"created": "Mon, 30 Jun 2008 12:44:53 GMT"
},
{
"version": "v7",
"created": "Tue, 8 Jul 2008 02:56:27 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Wang",
"Zhi-Gang",
""
]
] |
0707.3737 | Noam Soker | Ehud Behar, Raanan Nordon, and Noam Soker (Technion, Israel) | A high-velocity transient outflow in Eta Carinae | Accepted by ApJ Letters | null | 10.1086/521787 | null | astro-ph | null | We analyze velocity profiles of the X-ray spectral lines emitted by the Eta
Carinae stellar binary at four epochs, just before the X-ray minimum
(associated with periastron) and more than two years before the minimum
(~apastron). The profiles are nicely resolved by the HETGS spectrometer on
board Chandra. Far from periastron, we find symmetrical lines that are more or
less centered at zero velocity. Closer to periastron, the lines broaden, shift
towards the blue, and become visibly asymmetric. While the quiescent X-ray
emission and slight (<200 km/sec) centroid shifts can be ascribed to the
ordinary continuous binary wind interaction and to the orbital velocity of the
secondary star, the observed high-velocity emission up to ~2,000 km/sec and the
abrupt flares during which it occurs can not. This leads us to interpret the
high-velocity flaring emission as due to a fast collimated outflow of ionized
gas.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:19:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Behar",
"Ehud",
"",
"Technion, Israel"
],
[
"Nordon",
"Raanan",
"",
"Technion, Israel"
],
[
"Soker",
"Noam",
"",
"Technion, Israel"
]
] |
0707.3738 | Omar Mustafa | Omar Mustafa and S.Habib Mazharimousavi | Non-Hermitian von Roos Hamiltonian's $\eta$-weak-pseudo-Hermiticity,
isospectrality and exact solvability | 11 pages, no figures, | J. Phys. A: Math. Theor. 41, 244020 (2008) | 10.1088/1751-8113/41/24/244020 | null | quant-ph | null | A complexified von Roos Hamiltonian is considered and a Hermitian first-order
intertwining differential operator is used to obtain the related position
dependent mass $\eta$-weak-pseudo-Hermitian Hamiltonians. Using a
Liouvillean-type change of variables, the $\eta$-weak-pseudo-Hermitian von Roos
Hamiltonians H(x) are mapped into the traditional Schrodinger Hamiltonian form
H(q), where exact isospectral correspondence between H(x) and H(q) is obtained.
Under a user-friendly position dependent mass settings, it is observed that for
each exactly-solvable $\eta$-weak-pseudo-Hermitian reference-Hamiltonian
H(q)there is a set of exactly-solvable $\eta$-weak-pseudo-Hermitian isospectral
target-Hamiltonians H(x). A non-Hermitian PT-symmetric Scarf II and a
non-Hermitian periodic-type PT-symmetric Samsonov-Roy potentials are used as
reference models and the corresponding $\eta$-weak-pseudo-Hermitian isospectral
target-Hamiltonians are obtained.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:24:48 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Dec 2007 10:32:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mustafa",
"Omar",
""
],
[
"Mazharimousavi",
"S. Habib",
""
]
] |
0707.3739 | Dmitri Golubev | D.S. Golubev and A.D. Zaikin | Non-local Andreev reflection in superconducting quantum dots | 10 pages, 5 figures | Phys. Rev. B 76, 184510 (2007) | 10.1103/PhysRevB.76.184510 | null | cond-mat.supr-con | null | With the aid of the Keldysh technique we develop a microscopic theory of
non-local electron transport in three-terminal NSN structures consisting of a
chaotic superconducting quantum dot attached to one superconducting and two
normal electrodes. Our theory fully accounts for non-equilibrium effects and
disorder in a superconducting terminal. We go beyond perturbation theory in
tunneling and derive a general expression for the system conductance matrix
which remains valid in both weak and strong tunneling limits. We demonstrate
that the proximity effect yields a decrease of crossed Andreev reflection
(CAR). Beyond weak tunneling limit the contribution of CAR to the non-local
conductance does not cancel that of direct electron transfer between two normal
terminals. We argue that temperature dependence of the non-local resistance of
NSN devices is determined by the two competing processes -- Andreev reflection
and charge imbalance -- and it has a pronounced peak occurring at the crossover
between these two processes. This behavior is in a good agreement with recent
experimental observations.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:25:46 GMT"
}
] | 2009-07-06T00:00:00 | [
[
"Golubev",
"D. S.",
""
],
[
"Zaikin",
"A. D.",
""
]
] |
0707.3740 | Hidenori Fukaya | Poul H. Damgaard and Hidenori Fukaya | Partially quenched chiral perturbation theory in the epsilon-regime | 40pages, 7figures, Minor changes, references added | Nucl.Phys.B793:160-191,2008 | 10.1016/j.nuclphysb.2007.10.010 | RIKEN-TH-110 | hep-lat hep-ph | null | We calculate meson correlators in the epsilon-regime within partially
quenched chiral perturbation theory. The valence quark masses and sea quark
masses can be chosen arbitrary and all non-degenerate. Taking some of the sea
quark masses to infinity, one obtains a smooth connection among the theories
with different number of flavors, as well as the quenched theory. These results
can be directly compared with lattice QCD simulations.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:29:26 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 11:06:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Damgaard",
"Poul H.",
""
],
[
"Fukaya",
"Hidenori",
""
]
] |
0707.3741 | Ke Wu | Ke Wu, Wei-Zhong Zhao and Han-Ying Guo | Difference Discrete Connection and Curvature on Cubic Lattice | 29 pages | Science in China Series A: Mathematics 49(2006)1458 | null | null | math-ph math.DG math.MP | null | In a way similar to the continuous case formally, we define in different but
equivalent manners the difference discrete connection and curvature on discrete
vector bundle over the regular lattice as base space. We deal with the
difference operators as the discrete counterparts of the derivatives based upon
the differential calculus on the lattice. One of the definitions can be
extended to the case over the random lattice. We also discuss the relation
between our approach and the lattice gauge theory and apply to the discrete
integrable systems.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:30:00 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Wu",
"Ke",
""
],
[
"Zhao",
"Wei-Zhong",
""
],
[
"Guo",
"Han-Ying",
""
]
] |
0707.3742 | Maxime Viallet | M. Viallet, H. Baty | Spatial simulations of the Kelvin-Helmholtz instability in astrophysical
jets | 10 pages, 14 figures, accepted for publication in A&A | null | null | null | astro-ph | null | The long term magnetohydrodynamic stability of magnetized
transonic/supersonic jets is numerically investigated using a spatial approach.
We focus on two-dimensional linearly-unstable slab configurations where the jet
is embedded in a flow-aligned uniform magnetic field of weak amplitude. We
compare our results with previous studies using a temporal approach where
longitudinally periodic domains were adopted. The finite-volume based versatile
advection code (VAC) is used to solve the full set of ideal compressible MHD
equations. We follow the development of Kelvin-Helmholtz modes that are driven
by a white noise perturbation continuously introduced at the jet inlet. No
noticeable difference is observed in spatial simulations versus analogous
temporal ones during the linear and early non-linear evolution of the
configuration. However, in the case of transonic flows, a different long-term
scenario occurs in our spatial runs. Indeed, after the large-scale disruption
of the flow, a sheath region of enhanced magnetic field encompassing the jet
core forms along the whole flow. This provides a partial stabilization
mechanism leading to enhanced stability for later times, which is almost
independent of the initial magnitude of the magnetic field. The implication of
this mechanism for the stability of astrophysical jets is discussed.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:47:33 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Viallet",
"M.",
""
],
[
"Baty",
"H.",
""
]
] |
0707.3743 | B Reville | B. Reville, J. G. Kirk, P. Duffy, S. O. Sullivan | A cosmic ray current driven instability in partially ionised media | 5 pages, 2 figures, accepted to A&A. Corrections made. Applications
added | null | 10.1051/0004-6361:20078336 | null | astro-ph | null | We investigate the growth of hydromagnetic waves driven by streaming cosmic
rays in the precursor environment of a supernova remnant shock. It is known
that transverse waves propagating parallel to the mean magnetic field are
unstable to anisotropies in the cosmic ray distribution, and may provide a
mechanism to substantially amplify the ambient magnetic field. We quantify the
extent to which temperature and ionisation fractions modify this picture. Using
a kinetic description of the plasma we derive the dispersion relation for a
collisionless thermal plasma with a streaming cosmic ray current. Fluid
equations are then used to discuss the effects of neutral-ion collisions. We
calculate the extent to which the environment into which the cosmic rays
propagate influences the growth of the magnetic field, and determines the range
of possible growth rates. If the cosmic ray acceleration is efficient, we find
that very large neutral fractions are required to stabilise the growth of the
non-resonant mode. For typical supernova parameters in our galaxy, thermal
effects do not significantly alter the growth rates. For weakly driven modes,
ion-neutral damping can dominate over the instability at more modest ionisation
fractions. In the case of a supernova shock interacting with a molecular
clouds, such as in RX J1713.7-3946, with high density and low ionisation, the
modes can be rapidly damped.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:48:08 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Sep 2007 12:30:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Reville",
"B.",
""
],
[
"Kirk",
"J. G.",
""
],
[
"Duffy",
"P.",
""
],
[
"Sullivan",
"S. O.",
""
]
] |
0707.3744 | Viki Joergens | V. Joergens and A. Mueller (Max-Planck Institute for Astronomy
Heidelberg) | 16-20 Jupiter mass RV companion orbiting the brown dwarf candidate
ChaHa8 | 8 pages, 1 figure, ApJ Letter in press | Astrophys.J.666:L113-L116,2007 | 10.1086/521825 | null | astro-ph | null | We report the discovery of a 16-20 Jupiter mass radial velocity companion
around the very young (~3 Myr) brown dwarf candidate ChaHa8 (M5.75-M6.5). Based
on high-resolution echelle spectra of ChaHa8 taken between 2000 and 2007 with
UVES at the VLT, a companion was detected through RV variability with a
semi-amplitude of 1.6 km/s. A Kepler fit to the data yields an orbital period
of the companion of 1590 days and an eccentricity of e=0.49. A companion
minimum mass M2sini between 16 and 20 Jupiter masses is derived when using
model-dependent mass estimates for the primary. The mass ratio q= M2/M1 might
be as small as 0.2 and, with a probability of 87%, it is less than 0.4. ChaHa8
harbors most certainly the lowest mass companion detected so far in a close (~
1 AU) orbit around a brown dwarf or very low-mass star. From the uncertainty in
the orbit solution, it cannot completely be ruled out that the companion has a
mass in the planetary regime. Its discovery is in any case an important step
towards RV planet detections around BDs. Further, ChaHa8 is the fourth known
spectroscopic brown dwarf or very low-mass binary system with an RV orbit
solution and the second known very young one.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:50:26 GMT"
}
] | 2010-01-28T00:00:00 | [
[
"Joergens",
"V.",
"",
"Max-Planck Institute for Astronomy\n Heidelberg"
],
[
"Mueller",
"A.",
"",
"Max-Planck Institute for Astronomy\n Heidelberg"
]
] |
0707.3745 | Rodin Andrei | Andrei Rodin | On Categorical Theory-Building: Beyond the Formal | 28 pages, no images | null | null | null | math.HO math.CT | null | I propose a notion of theory motivated by Category theory.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 13:56:02 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Rodin",
"Andrei",
""
]
] |
0707.3746 | Emmanuel Roy | Emmanuel Roy | Ergodic properties of Poissonian ID processes | Published at http://dx.doi.org/10.1214/009117906000000692 in the
Annals of Probability (http://www.imstat.org/aop/) by the Institute of
Mathematical Statistics (http://www.imstat.org) | Annals of Probability 2007, Vol. 35, No. 2, 551-576 | 10.1214/009117906000000692 | IMS-AOP-AOP0190 | math.PR | null | We show that a stationary IDp process (i.e., an infinitely divisible
stationary process without Gaussian part) can be written as the independent sum
of four stationary IDp processes, each of them belonging to a different class
characterized by its L\'{e}vy measure. The ergodic properties of each class
are, respectively, nonergodicity, weak mixing, mixing of all order and
Bernoullicity. To obtain these results, we use the representation of an IDp
process as an integral with respect to a Poisson measure, which, more
generally, has led us to study basic ergodic properties of these objects.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:00:18 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Roy",
"Emmanuel",
""
]
] |
0707.3747 | Guido Kings | Kenichi Bannai and Guido Kings | p-adic elliptic polylogarithm, p-adic Eisenstein series and Katz measure | 40 pages | Amer. J. Math vol. 132, no. 6, (2010) 1609-1654 | null | null | math.NT math.AG | null | The specializations of the motivic elliptic polylog are called motivic
Eisenstein classes. For applications to special values of L-Functions, it is
important to compute the realizations of these classes. In this paper, we prove
that the syntomic realization of the motivic Eisenstein classes, restricted to
the ordinary locus of the modular curve, may be expressed using p-adic
Eisenstein-Kronecker series. These p-adic modular forms are defined using the
two-variable p-adic measure with values in p-adic modular forms constructed by
Katz.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:13:19 GMT"
}
] | 2010-12-06T00:00:00 | [
[
"Bannai",
"Kenichi",
""
],
[
"Kings",
"Guido",
""
]
] |
0707.3748 | Mikhail Mazin | Mikhail Mazin | Parshin Residues via Coboundary Operators | 18 pages; 5 figures; Title changed; Presentation significantly
changed; All the proofs filled in | Michigan Math. J. 61 (2012), no. 3, pp. 651---670 | null | null | math.AG math.GT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The article consist of two main parts: an analog of the Leray Theory for
Singular Varieties and its application to the Theory of Parshin's Residues. The
first part is independent from the second. It uses the theory of Whitney
stratifications. The second part is an application of the first. In particular,
a geometric and very transparent proof of the Parshin's Reciprocity Law for
residues is given.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:01:48 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Oct 2009 04:30:57 GMT"
},
{
"version": "v3",
"created": "Sun, 5 Dec 2010 17:49:03 GMT"
}
] | 2015-03-13T00:00:00 | [
[
"Mazin",
"Mikhail",
""
]
] |
0707.3749 | Timothy Namsoo | ZEUS Collaboration: S. Chekanov, et al | Three- and four-jet final states in photoproduction at HERA | 50 pages, 15 figures, 22 tables, submitted to Nucl. Phys. B | Nucl.Phys.B792:1-47,2008 | 10.1016/j.nuclphysb.2007.08.021 | null | hep-ex | null | Three- and four-jet final states have been measured in photoproduction at
HERA using the ZEUS detector with an integrated luminosity of 121 pb^-1. The
results are presented for jets with transverse energy E_T^jet>6 GeV and
pseudorapidity |eta^jet|<2.4, in the kinematic region given by the virtuality
of the photon Q^2<1 GeV^2 and the inelasticity 0.2<y<0.85 and in two mass
regions defined as 25<M_nj<50 GeV and M_nj>50 GeV, where M_nj is the invariant
mass of the n-jet system. The four-jet photoproduction cross section has been
measured for the first time and represents the highest-order process studied at
HERA. Both the three- and four-jet cross sections have been compared with
leading-logarithmic parton-shower Monte Carlo models, with and without
multi-parton interactions. The three-jet cross sections have been compared to
an order(alpha alpha_s^2) perturbative QCD calculation.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:03:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"ZEUS Collaboration",
"",
""
],
[
"Chekanov",
"S.",
""
]
] |
0707.3750 | Guillaume Collet | Rumen Andonov (IRISA), Guillaume Collet (IRISA), Jean-Fran\c{c}ois
Gibrat (MIG), Antoine Marin (MIG), Vincent Poirriez (LAMIH), Nikola Yanev
(IRISA) | Recent Advances in Solving the Protein Threading Problem | null | null | null | null | q-bio.QM cs.DC | null | The fold recognition methods are promissing tools for capturing the structure
of a protein by its amino acid residues sequence but their use is still
restricted by the needs of huge computational resources and suitable efficient
algorithms as well. In the recent version of FROST (Fold Recognition Oriented
Search Tool) package the most efficient algorithm for solving the Protein
Threading Problem (PTP) is implemented due to the strong collaboration between
the SYMBIOSE group in IRISA and MIG in Jouy-en-Josas. In this paper, we present
the diverse components of FROST, emphasizing on the recent advances in
formulating and solving new versions of the PTP and on the way of solving on a
computer cluster a million of instances in a easonable time.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:05:59 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 12:45:26 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Andonov",
"Rumen",
"",
"IRISA"
],
[
"Collet",
"Guillaume",
"",
"IRISA"
],
[
"Gibrat",
"Jean-François",
"",
"MIG"
],
[
"Marin",
"Antoine",
"",
"MIG"
],
[
"Poirriez",
"Vincent",
"",
"LAMIH"
],
[
"Yanev",
"Nikola",
"",
"IRISA"
]
] |
0707.3751 | Paul R. Anderson | Paul R. Anderson, Emil Mottola, and Ruslan Vaulin | Stress Tensor from the Trace Anomaly in Reissner-Nordstrom Spacetimes | 43 pages, 12 figures | Phys.Rev.D76:124028,2007 | 10.1103/PhysRevD.76.124028 | LA-UR 07-4898 | gr-qc | null | The effective action associated with the trace anomaly provides a general
algorithm for approximating the expectation value of the stress tensor of
conformal matter fields in arbitrary curved spacetimes. In static, spherically
symmetric spacetimes, the algorithm involves solving a fourth order linear
differential equation in the radial coordinate r for the two scalar auxiliary
fields appearing in the anomaly action, and its corresponding stress tensor. By
appropriate choice of the homogeneous solutions of the auxiliary field
equations, we show that it is possible to obtain finite stress tensors on all
Reissner-Nordstrom event horizons, including the extreme Q=M case. We compare
these finite results to previous analytic approximation methods, which yield
invariably an infinite stress-energy on charged black hole horizons, as well as
with detailed numerical calculations that indicate the contrary. The
approximation scheme based on the auxiliary field effective action reproduces
all physically allowed behaviors of the quantum stress tensor, in a variety of
quantum states, for fields of any spin, in the vicinity of the entire family (0
le Q le M) of RN horizons.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:34:04 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 23:27:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Anderson",
"Paul R.",
""
],
[
"Mottola",
"Emil",
""
],
[
"Vaulin",
"Ruslan",
""
]
] |
0707.3752 | Robert B. Griffiths | Robert B. Griffiths | Types of quantum information | Minor changes so as to agree with published version | Phys. Rev. A 76 (Dec. 2007) 062320 | 10.1103/PhysRevA.76.062320 | null | quant-ph | null | Quantum, in contrast to classical, information theory, allows for different
incompatible types (or species) of information which cannot be combined with
each other. Distinguishing these incompatible types is useful in understanding
the role of the two classical bits in teleportation (or one bit in one-bit
teleportation), for discussing decoherence in information-theoretic terms, and
for giving a proper definition, in quantum terms, of ``classical information.''
Various examples (some updating earlier work) are given of theorems which
relate different incompatible kinds of information, and thus have no
counterparts in classical information theory.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:24:27 GMT"
},
{
"version": "v2",
"created": "Sat, 22 Dec 2007 22:36:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Griffiths",
"Robert B.",
""
]
] |
0707.3753 | Angela Sestito | Angela Sestito | Detection of incompatible properties | 25 pages, 2 figures | null | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In a typical two-slits experiments we face the question whether it is
possible or not to attain knowledge about properties incompatible with
Which-Slit property together with the measurement of the final impact point. A
wide family of solutions is concretely found and an ideal experiment realizing
such a detection is designed, relatively to the detection of three such
incompatible properties. In the case of four incompatible properties, general
conditions for the existence of solutions are singled out and a particular
family of solutions is provided.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:24:43 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Aug 2008 16:58:18 GMT"
}
] | 2008-08-21T00:00:00 | [
[
"Sestito",
"Angela",
""
]
] |
0707.3754 | Thomas Unger | Vincent Astier, Thomas Unger | A hermitian analogue of the Broecker-Prestel theorem | Final pre-publication version | Indag. Math. (N.S.) 19 (2008), no. 3, 349-358 | 10.1016/S0019-3577(09)00007-X | null | math.RA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Broecker-Prestel local-global principle characterizes weak isotropy of
quadratic forms over a formally real field in terms of weak isotropy over the
henselizations and isotropy over the real closures of that field. A hermitian
analogue of this principle is presented for algebras of index at most two. An
improved result is also presented for algebras with a decomposable involution,
algebras of pythagorean index at most two, and algebras over SAP and ED fields.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:26:54 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Sep 2007 14:43:21 GMT"
},
{
"version": "v3",
"created": "Mon, 6 Feb 2012 16:38:53 GMT"
}
] | 2012-02-07T00:00:00 | [
[
"Astier",
"Vincent",
""
],
[
"Unger",
"Thomas",
""
]
] |
0707.3755 | Klaus Kirsten | Klaus Kirsten and Paul Loya | Computation of determinants using contour integrals | 15 pages, to appear in American Journal of Physics | Am.J.Phys.76:60-64,2008 | 10.1119/1.2794348 | null | hep-th | null | It is shown how the pre-exponential factor of the Feynman propagator for a
large class of potentials can be computed using contour integrals. This is of
direct relevance in the context of tunnelling processes in quantum theories.
The prerequisites for this analysis are accessible to advanced undergraduate
students and involve only introductory courses in ordinary differential
equations and complex variables.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:34:18 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kirsten",
"Klaus",
""
],
[
"Loya",
"Paul",
""
]
] |
0707.3756 | Lars Kadison | Lars Kadison | Finite depth and Jacobson-Bourbaki correspondence | 26 pp., depth three towers with new section on finite depth, and
corrections | null | null | null | math.QA math.OA | null | We introduce a notion of depth three tower of three rings C < B < A with
depth two ring extension A | B recovered when B = C. If A = \End B_C and B | C
is a Frobenius extension, this captures the notion of depth three for a
Frobenius extension in arXiv:math/0107064 and arXiv:math/0108067, such that if
B | C is depth three, then A | C is depth two (a phenomenon of finite depth
subfactors, see arXiv:math/0006057). We provide a similar definition of finite
depth Frobenius extension with embedding theorem utilizing a depth three
subtower of the Jones tower. If A, B and C correspond to a tower of subgroups G
> H > K via the group algebra over a fixed base ring, the depth three condition
is the condition that subgroup K has normal closure K^G contained in H. For a
depth three tower of rings, there is a pre-Galois theory for the ring \End
{}_BA_C and coring (A \o_B A)^C involving Morita context bimodules and left
coideal subrings. This is applied in two sections to a specialization of a
Jacobson-Bourbaki correspondence theorem for augmented rings to depth two
extensions with depth three intermediate division rings.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:45:48 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Kadison",
"Lars",
""
]
] |
0707.3757 | Rolf Nahnhauer | R. Nahnhauer (1), A. A. Rostovtsev (2), D. Tosi (1) ((1)Deutsches
Elektronen-Synchrotron, DESY, Zeuthen, Germany (2)Institute for Theoretical
and Experimental Physics, ITEP, Moscow, Russia) | Permafrost - An Alternative Target Material for Ultra High Energy
Neutrino Detection? | 8 pages, 9 figures | Nucl.Instrum.Meth.A587:29-34,2008 | 10.1016/j.nima.2007.12.034 | null | astro-ph | null | The detection of cosmic neutrinos with energies above 1017 eV got growing
interest during recent years. Possible target materials for in-matter arrays of
~100 km3 size under discussion are water, ice and rock salt. Here we propose to
investigate permafrost as an additional alternative, covering ~20% of Earth
land surface and reaching down to more than 1000 m depth at certain locations.
If sufficiently large attenuation lengths for radio and acoustic signals can be
demonstrated by in-situ measurements, the construction of a large hybrid array
within this material may be possible in the Northern hemisphere. Properties and
problems of a possible location in Siberia are discussed below. Some acoustic
data are compared to laboratory measurements using "artificial" permafrost.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:55:13 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Nahnhauer",
"R.",
""
],
[
"Rostovtsev",
"A. A.",
""
],
[
"Tosi",
"D.",
""
]
] |
0707.3758 | Victor Przyjalkowski | Victor Przyjalkowski | On Landau--Ginzburg models for Fano varieties | 11 pages; misprint in the Landau--Ginzburg model for V_{16} is
corrected | Commun. Number Theory Phys., 1:4 (2008), 713-728 | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We observe a method for finding weak Landau-Ginzburg models for Fano
varieties and find them for smooth Fano threefolds of genera 9, 10, and 12.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:57:08 GMT"
},
{
"version": "v2",
"created": "Sun, 2 Mar 2008 09:52:45 GMT"
},
{
"version": "v3",
"created": "Thu, 13 Nov 2008 15:56:15 GMT"
}
] | 2018-08-07T00:00:00 | [
[
"Przyjalkowski",
"Victor",
""
]
] |
0707.3759 | Jes\'us Clemente-Gallardo | J. Clemente-Gallardo and G. Marmo | The space of density states in geometrical quantum mechanics | Amslatex, 18 pages, 4 figures | Chapter in the book "Differential Geometric Methods in Mechanics
and Field Theory", Volume in Honour of Willy Sarlet, Eds. F. Cantrijn, M.
Crampin and B. Langerock, Gent Academia Press 2007, pag. 35-56 | null | null | quant-ph | null | We present a geometrical description of the space of density states of a
quantum system of finite dimension. After presenting a brief summary of the
geometrical formulation of Quantum Mechanics, we proceed to describe the space
of density states $\D(\Hil)$ from a geometrical perspective identifying the
stratification associated to the natural $GL(\Hil)$--action on $\D(\Hil)$ and
some of its properties. We apply this construction to the cases of quantum
systems of two and three levels.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 14:57:52 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Clemente-Gallardo",
"J.",
""
],
[
"Marmo",
"G.",
""
]
] |
0707.3760 | Alessandro Giuliani | Alessandro Giuliani, Joel L. Lebowitz and Elliott H. Lieb | Striped phases in two dimensional dipole systems | 20 pages, 1 figure | Phys. Rev. B 76, 184426 (2007) | 10.1103/PhysRevB.76.184426 | null | cond-mat.stat-mech math-ph math.MP | null | We prove that a system of discrete 2D in-plane dipoles with four possible
orientations, interacting via a 3D dipole-dipole interaction plus a nearest
neighbor ferromagnetic term, has periodic striped ground states. As the
strength of the ferromagnetic term is increased, the size of the stripes in the
ground state increases, becoming infinite, i.e., giving a ferromagentic ground
state, when the ferromagentic interaction exceeds a certain critical value. We
also give a rigorous proof of the reorientation transition in the ground state
of a 2D system of discrete dipoles with six possible orientations, interacting
via a 3D dipole-dipole interaction plus a nearest neighbor antiferromagnetic
term. As the strength of the antiferromagnetic term is increased the ground
state flips from being striped and in-plane to being staggered and
out-of-plane. An example of a rotator model with a sinusoidal ground state is
also discussed.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:03:06 GMT"
}
] | 2012-09-19T00:00:00 | [
[
"Giuliani",
"Alessandro",
""
],
[
"Lebowitz",
"Joel L.",
""
],
[
"Lieb",
"Elliott H.",
""
]
] |
0707.3761 | Tim Huege | T. Huege, R. Ulrich, R. Engel (Forschungszentrum Karlsruhe, IK) | Energy and composition sensitivity of geosynchrotron radio emission from
EAS | 4 pages, to be published in the Proceedings of the 30th International
Cosmic Ray Conference 2007, Merida, Mexico | null | null | null | astro-ph | null | We analyse the sensitivity of geosynchrotron radio emission from inclined
extensive air showers to the energy and mass of primary cosmic rays. We
demonstrate that radio emission measurements at suitable lateral distances can
infer both the number of electrons and positrons in the shower maximum and the
atmospheric depth of the maximum on a shower-to-shower basis. Alternatively,
measurements at a fixed lateral distance but in two different observing
frequency bands yield comparable information. An RMS error of 5% in the
determination of the number of electrons and positrons at shower maximum can be
achieved. Through the determination of these quantities, geosynchrotron
radiation provides access to the energy and mass of primary cosmic rays on a
shower-to-shower basis.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:12:45 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Huege",
"T.",
"",
"Forschungszentrum Karlsruhe, IK"
],
[
"Ulrich",
"R.",
"",
"Forschungszentrum Karlsruhe, IK"
],
[
"Engel",
"R.",
"",
"Forschungszentrum Karlsruhe, IK"
]
] |
0707.3762 | Hans-Andreas Engel | Hans-Andreas Engel | Hanle Effect near Boundaries | 4 pages, 2 figures | Phys. Rev. B 77, 125302 (2008) | 10.1103/PhysRevB.77.125302 | null | cond-mat.mes-hall | null | The Hanle effect describes suppression of spin polarization due to precession
in a magnetic field. This is a standard spintronics tool and it gives access to
the spin lifetime of samples in which spins are generated homogeneously. We
examine the Hanle effect when spins are generated at a boundary of a diffusive
sample by the extrinsic spin Hall effect. We show that the Hanle curve is
spatially dependent and that the "apparent" spin lifetime, given by its inverse
half-width, is shorter near the boundary even if the spin relaxation rate is
homogenous.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:13:32 GMT"
}
] | 2008-03-05T00:00:00 | [
[
"Engel",
"Hans-Andreas",
""
]
] |
0707.3763 | Tim Huege | T. Huege, R. Ulrich, R. Engel (Forschungszentrum Karlsruhe, IK) | REAS2: CORSIKA-based Monte Carlo simulations of geosynchrotron radio
emission | 4 pages, to be published in the Proceedings of the 30th International
Cosmic Ray Conference 2007, Merida, Mexico | null | null | null | astro-ph | null | Simulations of geosynchrotron radio emission from extensive air showers
performed with the Monte Carlo code REAS1 used analytical parameterisations to
describe the spatial, temporal, energy and angular particle distributions in
air showers. The successor REAS2 replaces these parameterisations with precise,
multi-dimensional histograms derived from per-shower CORSIKA simulations. REAS2
allows an independent selection between parameterisation and histogram for each
of the relevant particle distributions, enabling us to study the changes
arising from using a more realistic air shower model in detail. We describe the
new simulation strategy and illustrate the effects introduced by the improved
air shower model.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:14:01 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Huege",
"T.",
"",
"Forschungszentrum Karlsruhe, IK"
],
[
"Ulrich",
"R.",
"",
"Forschungszentrum Karlsruhe, IK"
],
[
"Engel",
"R.",
"",
"Forschungszentrum Karlsruhe, IK"
]
] |
0707.3764 | Constantinos Siettos | M.E. Kavousanakis, L. Russo, C. I. Siettos, A. G. Boudouvis, G.C.
Georgiou | A timestepper approach for the systematic bifurcation and stability
analysis of polymer extrusion dynamics | null | J. Non-Newtonian Fluid Mechanics, 151, 59-68 (2008) | null | null | math.DS | null | We discuss how matrix-free/timestepper algorithms can efficiently be used
with dynamic non-Newtonian fluid mechanics simulators in performing systematic
stability/bifurcation analysis. The timestepper approach to bifurcation
analysis of large scale systems is applied to the plane Poiseuille flow of an
Oldroyd-B fluid with non-monotonic slip at the wall, in order to further
investigate a mechanism of extrusion instability based on the combination of
viscoelasticity and nonmonotonic slip. Due to the nonmonotonicity of the slip
equation the resulting steady-state flow curve is nonmonotonic and unstable
steady-states appear in the negative-slope regime. It has been known that
self-sustained oscillations of the pressure gradient are obtained when an
unstable steady-state is perturbed [Fyrillas et al., Polymer Eng. Sci. 39
(1999) 2498-2504].
Treating the simulator of a distributed parameter model describing the
dynamics of the above flow as an input-output black-box timestepper of the
state variables, stable and unstable branches of both equilibrium and periodic
oscillating solutions are computed and their stability is examined. It is shown
for the first time how equilibrium solutions lose stability to oscillating ones
through a subcritical Hopf bifurcation point which generates a branch of
unstable limit cycles and how the stable periodic solutions lose their
stability through a critical point which marks the onset of the unstable limit
cycles. This implicates the coexistence of stable equilibria with stable and
unstable periodic solutions in a narrow range of volumetric flow rates.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:14:18 GMT"
}
] | 2013-10-02T00:00:00 | [
[
"Kavousanakis",
"M. E.",
""
],
[
"Russo",
"L.",
""
],
[
"Siettos",
"C. I.",
""
],
[
"Boudouvis",
"A. G.",
""
],
[
"Georgiou",
"G. C.",
""
]
] |
0707.3765 | Nikolay Kiselev Mr. | N. S. Kiselev, I. E. Dragunov, U.K. Roessler, A.N. Bogdanov | Exchange shift of stripe domains in antiferromagnetically coupled
multilayers | 4 pages, 3 figures | null | 10.1063/1.2793626 | null | cond-mat.mes-hall | null | Antiferromagnetically coupled multilayers with perpendicular anisotropy, as
[CoPt]/Ru, Co/Ir, Fe/Au, display ferromagnetic stripe phases as the ground
states. It is theoretically shown that the antiferromagnetic interlayer
exchange causes a relative shift of domains in adjacent layers. This ``exchange
shift'' is responsible for several recently observed effects: an anomalous
broadening of domain walls, the formation of so-called ``tiger-tail'' patterns,
and a ``mixed state'' of antiferromagnetic and ferromagnetic domains in
[CoPt]/Ru multilayers. The derived analitical relations between the values of
the shift and the strength of antiferromagnetic coupling provide an effective
method for a quantitative determination of the interlayer exchange
interactions.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:36:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kiselev",
"N. S.",
""
],
[
"Dragunov",
"I. E.",
""
],
[
"Roessler",
"U. K.",
""
],
[
"Bogdanov",
"A. N.",
""
]
] |
0707.3766 | Philippe Ruelle | Philippe Ruelle | Wind on the boundary for the Abelian sandpile model | 26 pages, 4 figures | J. Stat. Mech. (2007) P09013 | 10.1088/1742-5468/2007/09/P09013 | null | cond-mat.stat-mech hep-th math-ph math.MP | null | We continue our investigation of the two-dimensional Abelian sandpile model
in terms of a logarithmic conformal field theory with central charge c=-2, by
introducing two new boundary conditions. These have two unusual features: they
carry an intrinsic orientation, and, more strangely, they cannot be imposed
uniformly on a whole boundary (like the edge of a cylinder). They lead to seven
new boundary condition changing fields, some of them being in highest weight
representations (weights -1/8, 0 and 3/8), some others belonging to
indecomposable representations with rank 2 Jordan cells (lowest weights 0 and
1). Their fusion algebra appears to be in full agreement with the fusion rules
conjectured by Gaberdiel and Kausch.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:51:56 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 20:22:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ruelle",
"Philippe",
""
]
] |
0707.3767 | Jure Dobnikar | N. Osterman, D. Babi\v{c}, I. Poberaj, J. Dobnikar, and P. Ziherl | Observation of condensed phases of quasi-planar core-softened colloids | null | Phys. Rev. Lett. 99, 248301 (2007) | 10.1103/PhysRevLett.99.248301 | null | cond-mat.soft cond-mat.stat-mech | null | We experimentally study the condensed phases of repelling core-softened
spheres in two dimensions. The dipolar pair repulsion between superparamagnetic
spheres trapped in a thin cell is induced by a transverse magnetic field and
softened by suitably adjusting the cell thickness. We scan a broad density
range and we materialize a large part of the theoretically predicted phases in
systems of core-softened particles, including expanded and close-packed
hexagonal, square, chain-like, stripe/labyrinthine, and honeycomb phase.
Further insight into their structure is provided by Monte Carlo simulations.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:30:02 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Osterman",
"N.",
""
],
[
"Babič",
"D.",
""
],
[
"Poberaj",
"I.",
""
],
[
"Dobnikar",
"J.",
""
],
[
"Ziherl",
"P.",
""
]
] |
0707.3768 | Alexander Gerlach | Alexander Hinderhofer, Ute Heinemeyer, Alexander Gerlach, Stefan
Kowarik, Robert M. J. Jacobs, Youichi Sakamoto, Toshiyasu Suzuki, Frank
Schreiber | Optical Properties of Pentacene and Perfluoropentacene Thin Films | 6 pages, 6 figures, submitted to J. Chem. Phys | null | 10.1063/1.2786992 | null | cond-mat.soft cond-mat.mtrl-sci | null | The optical properties of pentacene (PEN) and perfluoropentacene(PFP) thin
films on various SiO2 substrates were studied using variable angle
spectroscopic ellipsometry. Structural characterization was performed using
X-ray reflectivity and atomic force microscopy. A uniaxial model with the optic
axis normal to the sample surface was used to analyze the ellipsometry data. A
Strong optical anisotropy was observed and enabled the direction of the
transition dipole of the absorption bands to be determined. Furthermore,
comparison of the optical constants of PEN and PFP thin films with the
absorption spectra of the monomers in solution shows significant changes due to
the crystalline environment. Relative to the monomer spectrum the HOMO-LUMO
transition observed in PEN (PFP) thin film is reduced by 210 meV (280 meV).
Surprisingly, a second absorption band in the PFP thin film shows a slight
blueshift (40 meV) compared to the spectrum of the monomer with its transition
dipole perpendicular to that of the first absorption band.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:31:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hinderhofer",
"Alexander",
""
],
[
"Heinemeyer",
"Ute",
""
],
[
"Gerlach",
"Alexander",
""
],
[
"Kowarik",
"Stefan",
""
],
[
"Jacobs",
"Robert M. J.",
""
],
[
"Sakamoto",
"Youichi",
""
],
[
"Suzuki",
"Toshiyasu",
""
],
[
"Schreiber",
"Frank",
""
]
] |
0707.3769 | Francisco Jose Herranz | Angel Ballesteros, Francisco J. Herranz and Orlando Ragnisco | Superintegrability on sl(2)-coalgebra spaces | 12 pages. Based on the contribution presented at the "XII
International Conference on Symmetry Methods in Physics", Yerevan (Armenia),
July 2006. To appear in Physics of Atomic Nuclei | Phys.Atom.Nucl.71:812-818,2008 | 10.1134/S1063778808050074 | null | math-ph math.MP nlin.SI | null | We review a recently introduced set of N-dimensional quasi-maximally
superintegrable Hamiltonian systems describing geodesic motions, that can be
used to generate "dynamically" a large family of curved spaces. From an
algebraic viewpoint, such spaces are obtained through kinetic energy
Hamiltonians defined on either the sl(2) Poisson coalgebra or a quantum
deformation of it. Certain potentials on these spaces and endowed with the same
underlying coalgebra symmetry have been also introduced in such a way that the
superintegrability properties of the full system are preserved. Several new N=2
examples of this construction are explicitly given, and specific Hamiltonians
leading to spaces of non-constant curvature are emphasized.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:32:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ballesteros",
"Angel",
""
],
[
"Herranz",
"Francisco J.",
""
],
[
"Ragnisco",
"Orlando",
""
]
] |
0707.3770 | Tibor Antal | Niko Beerenwinkel, Tibor Antal, David Dingli, Arne Traulsen, Kenneth
W. Kinzler, Victor E. Velculescu, Bert Vogelstein, Martin A. Nowak | Genetic progression and the waiting time to cancer | Details available as supplementary material at
http://www.people.fas.harvard.edu/~antal/publications.html | PLoS Comput Biol 3(11): e225 (2007) | 10.1371/journal.pcbi.0030225 | null | q-bio.PE q-bio.QM | null | Cancer results from genetic alterations that disturb the normal cooperative
behavior of cells. Recent high-throughput genomic studies of cancer cells have
shown that the mutational landscape of cancer is complex and that individual
cancers may evolve through mutations in as many as 20 different
cancer-associated genes. We use data published by Sjoblom et al. (2006) to
develop a new mathematical model for the somatic evolution of colorectal
cancers. We employ the Wright-Fisher process for exploring the basic parameters
of this evolutionary process and derive an analytical approximation for the
expected waiting time to the cancer phenotype. Our results highlight the
relative importance of selection over both the size of the cell population at
risk and the mutation rate. The model predicts that the observed genetic
diversity of cancer genomes can arise under a normal mutation rate if the
average selective advantage per mutation is on the order of 1%. Increased
mutation rates due to genetic instability would allow even smaller selective
advantages during tumorigenesis. The complexity of cancer progression thus can
be understood as the result of multiple sequential mutations, each of which has
a relatively small but positive effect on net cell growth.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:39:48 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Beerenwinkel",
"Niko",
""
],
[
"Antal",
"Tibor",
""
],
[
"Dingli",
"David",
""
],
[
"Traulsen",
"Arne",
""
],
[
"Kinzler",
"Kenneth W.",
""
],
[
"Velculescu",
"Victor E.",
""
],
[
"Vogelstein",
"Bert",
""
],
[
"Nowak",
"Martin A.",
""
]
] |
0707.3771 | Lidia Makarova | L. Makarova, D. Makarov | Evolution of dwarf galaxies in the Centaurus A group | To appear in proceedings IAU Symp 244, 'Dark Galaxies and Lost
Baryons', June 2007 | null | 10.1017/S1743921307014160 | null | astro-ph | null | We consider star formation properties of dwarf galaxies in Cen A group
observed within our HST/ACS projects number 9771 and 10235. We model
color-magnitude diagrams of the galaxies under consideration and measure star
formation rate and metallicity dependence on time. We study environmental
dependence of the galaxy evolution and probable origin of the dwarf galaxies in
the group.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:22:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Makarova",
"L.",
""
],
[
"Makarov",
"D.",
""
]
] |
0707.3772 | Francisco Jose Herranz | Francisco J. Herranz and Angel Ballesteros | Superintegrability on N-dimensional spaces of constant curvature from
so(N+1) and its contractions | 14 pages. Based on the contribution presented at the "XII
International Conference on Symmetry Methods in Physics", Yerevan (Armenia),
July 2006. To appear in Physics of Atomic Nuclei | Phys.Atom.Nucl.71:905-913,2008 | 10.1134/S1063778808050207 | null | math-ph math.MP nlin.SI | null | The Lie-Poisson algebra so(N+1) and some of its contractions are used to
construct a family of superintegrable Hamiltonians on the ND spherical,
Euclidean, hyperbolic, Minkowskian and (anti-)de Sitter spaces. We firstly
present a Hamiltonian which is a superposition of an arbitrary central
potential with N arbitrary centrifugal terms. Such a system is quasi-maximally
superintegrable since this is endowed with 2N-3 functionally independent
constants of the motion (plus the Hamiltonian). Secondly, we identify two
maximally superintegrable Hamiltonians by choosing a specific central potential
and finding at the same time the remaining integral. The former is the
generalization of the Smorodinsky-Winternitz system to the above six spaces,
while the latter is a generalization of the Kepler-Coulomb potential, for which
the Laplace-Runge-Lenz N-vector is also given. All the systems and constants of
the motion are explicitly expressed in a unified form in terms of ambient and
polar coordinates as they are parametrized by two contraction parameters
(curvature and signature of the metric).
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:57:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Herranz",
"Francisco J.",
""
],
[
"Ballesteros",
"Angel",
""
]
] |
0707.3773 | Dimiter Vassilev | Stefan Ivanov, Dimiter Vassilev, Simeon Zamkovoy | Conformal paracontact curvature and the local flatness theorem | 18 pages, substantial clarification of the integrability condition in
dimension 3 in both CR and para CR cases, CR-part shortened | Geom. Dedicata 144 (2010), 79-100. | null | MPIM2007-90 | math.DG math.AP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A curvature-type tensor invariant called para contact (pc) conformal
curvature is defined on a paracontact manifold. It is shown that a paracontact
manifold is locally paracontact conformal to the hyperbolic Heisenberg group or
to a hyperquadric of neutral signature if and only if the pc conformal
curvature vanishes. In the three dimensional case the corresponding result is
achieved through employing a certain symmetric (0,2) tensor. The well known
result of Cartan-Chern-Moser giving necessary and sufficient condition a
CR-structure to be CR equivalent to a hyperquadric in the complex vector space
is presented in-line with the paracontact case. An explicit formula for the
regular part of a solution to the sub-ultrahyperbolic Yamabe equation on the
hyperbolic Heisenberg group is shown.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 15:58:50 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Dec 2008 12:10:34 GMT"
}
] | 2010-03-12T00:00:00 | [
[
"Ivanov",
"Stefan",
""
],
[
"Vassilev",
"Dimiter",
""
],
[
"Zamkovoy",
"Simeon",
""
]
] |
0707.3774 | Katharina Durstberger | Katharina Durstberger | Spin geometry of entangled qubits under bilocal decoherence modes | 12 pages, 3 figures | Phys. Lett. A 372 (2008) 1789 - 1798 | 10.1016/j.physleta.2007.10.073 | null | quant-ph | null | The Lindblad generators of the master equation define which kind of
decoherence happens in an open quantum system. We are working with a two qubit
system and choose the generators to be projection operators on the eigenstates
of the system and unitary bilocal rotations of them. The resulting decoherence
modes are studied in detail. Besides the general solutions we investigate the
special case of maximally entangled states - the Bell singlet states. The
results are depicted in the so-called spin geometry picture which allows to
illustrate the evolution of the (nonlocal) correlations stored in a certain
state. The question for which conditions the path traced out in the geometric
picture depends only on the relative angle between the bilocal rotations is
addressed.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:25:30 GMT"
}
] | 2010-08-05T00:00:00 | [
[
"Durstberger",
"Katharina",
""
]
] |
0707.3775 | Dorothy Buck | Dorothy Buck and Erica Flapan | Predicting Knot or Catenane Type of Site-Specific Recombination Products | 17 pages, 4 figures. Revised to include link to the companion paper,
arXiv:0707.3896v1, that provides topological proofs underpinning the
conclusions of the current paper. References updated | null | null | null | q-bio.BM q-bio.QM | null | Site-specific recombination on supercoiled circular DNA yields a variety of
knotted or catenated products. We develop a model of this process, and give
extensive experimental evidence that the assumptions of our model are
reasonable. We then characterize all possible knot or catenane products that
arise from the most common substrates. We apply our model to tightly prescribe
the knot or catenane type of previously uncharacterized data.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:29:52 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 00:23:34 GMT"
}
] | 2007-08-07T00:00:00 | [
[
"Buck",
"Dorothy",
""
],
[
"Flapan",
"Erica",
""
]
] |
0707.3776 | Torsten Rudolf | T. Rudolf, Ch. Kant, F. Mayr, J. Hemberger, V. Tsurkan, and A. Loidl | Polar phonons and spin-phonon coupling in HgCr2S4 and CdCr2S4 | 8 pages, 8 figures | Phys. Rev. B 76, 174307 (2007) | 10.1103/PhysRevB.76.174307 | null | cond-mat.str-el | null | Polar phonons of HgCr2S4 and CdCr2S4 are studied by far-infrared spectroscopy
as a function of temperature and external magnetic field. Eigenfrequencies,
damping constants, effective plasma frequencies and Lyddane-Sachs-Teller
relations, and effective charges are determined. Ferromagnetic CdCr2S4 and
antiferromagnetic HgCr2S4 behave rather similar. Both compounds are dominated
by ferromagnetic exchange and although HgCr2S4 is an antiferromagnet, no phonon
splitting can be observed at the magnetic phase transition. Temperature and
magnetic field dependence of the eigenfrequencies show no anomalies indicating
displacive polar soft mode behavior. However, significant effects are detected
in the temperature dependence of the plasma frequencies indicating changes in
the nature of the bonds and significant charge transfer. In HgCr2S4 we provide
experimental evidence that the magnetic field dependence of specific polar
modes reveal shifts exactly correlated with the magnetization showing
significant magneto-dielectric effects even at infrared frequencies.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:18:35 GMT"
}
] | 2008-06-26T00:00:00 | [
[
"Rudolf",
"T.",
""
],
[
"Kant",
"Ch.",
""
],
[
"Mayr",
"F.",
""
],
[
"Hemberger",
"J.",
""
],
[
"Tsurkan",
"V.",
""
],
[
"Loidl",
"A.",
""
]
] |
0707.3777 | Susan G. Williams | Daniel S. Silver and Susan G. Williams | Nonfibered knots and representation shifts | 8 pages, no figures | null | null | null | math.GT math.DS | null | The authors conjectured previously that a knot is nonfibered if and only if
its infinite cyclic cover has uncountably many finite covers. We prove the
conjecture for a class of knots that includes all knots of genus 1, using
techniques from symbolic dynamics.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:21:29 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Silver",
"Daniel S.",
""
],
[
"Williams",
"Susan G.",
""
]
] |
0707.3778 | Branko Guberina | Branko Guberina | Renormalization group running cosmologies - from a scale setting to
holographic dark energy | Invited plenary talk given at the 2nd International Conference on
Quantum Theories and Renormalization Group in Gravity and Cosmology (IRGAC
2006), Barcelona, Catalonia, Spain, July 11-15, 2006 | null | null | null | gr-qc astro-ph hep-ph hep-th | null | A scale-dependent cosmological constant $\Lambda$ and the Newton constant G
emerge naturally in quantum field theory in a curved space-time background
leading to renormalization group running cosmologies. A scale-setting procedure
is discussed in these cosmological models and the interpretation of the scale
is emphasized. This setup introduces dark energy without invoking
quintessence-like fields and can be applied to a variety of problems. The
scale-dependent $\Lambda$ and G are also naturally incorporated into the
generalized holographic dark energy model, and applied to different aspects of
cosmology.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:32:12 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Guberina",
"Branko",
""
]
] |
0707.3779 | A. Lobel | A. Lobel (Royal Observatory of Belgium) | Modeling DACs in UV Lines of Massive Hot Stars | 3 pages, 3 figures. To appear in Clumping in Hot Star Winds, Proc. of
Int. Workshop, 18-22 June 2007, Potsdam, Universitats-Verlag, 2007. URN at
the German National Library, Eds. W.-R. Hamann, A. Feldmeier, and L.
Oskinova. Publ. of the Univ. of Potsdam, Germany. More information about
Wind3D at http://alobel.freeshell.org/conference.html | null | null | null | astro-ph | null | We apply the 3-dimensional radiative transport code Wind3D to 3D hydrodynamic
models of Corotating Interaction Regions to fit the detailed variability of
Discrete Absorption Components observed in Si IV UV resonance lines of HD 64760
(B0.5 Ib). We discuss important effects of the hydrodynamic input parameters on
these large-scale equatorial wind structures that determine the detailed
morphology of the DACs computed with 3D transfer. The best fit model reveals
that the CIR in HD 64760 is produced by a source at the base of the wind that
lags behind the stellar surface rotation. The non-corotating coherent wind
structure is an extended density wave produced by a local increase of only 0.6
% in the smooth symmetric wind mass-loss rate.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 16:44:13 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Lobel",
"A.",
"",
"Royal Observatory of Belgium"
]
] |
0707.3780 | Vicente Bitrian | Joaquim Trull\`as and Vicente Bitri\'an | Polarization effects on the dielectric properties of molten AgI | 5 pages, 5 figures. Proceeding of the XIII International Conference
on Liquid and Amorphous Metals (Ekaterinburg, Russia, July 8-14 2007).
Equation (13) corrected | null | null | null | cond-mat.soft cond-mat.stat-mech | null | The results are reported of molecular dynamics simulations of the static
longitudinal dielectric and response functions for molten AgI at 923 K using
two ionic models. The first one is a rigid ion model, while in the second the
induced dipole moments of the anions are added to the effective pair potentials
of the first. It is derived theoretically that the dielectric functions for the
polarizable ion model are determined by spatial correlations of charge and
dipole moment densities. The charge structure factor at long wavelengths is
also studied.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:01:33 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 19:04:30 GMT"
}
] | 2007-09-03T00:00:00 | [
[
"Trullàs",
"Joaquim",
""
],
[
"Bitrián",
"Vicente",
""
]
] |
0707.3781 | Paolo Liberatore | Paolo Liberatore | Bijective Faithful Translations among Default Logics | Removed one useless section | null | 10.1093/logcom/ext073 | null | cs.AI cs.LO | null | In this article, we study translations between variants of defaults logics
such that the extensions of the theories that are the input and the output of
the translation are in a bijective correspondence. We assume that a translation
can introduce new variables and that the result of translating a theory can
either be produced in time polynomial in the size of the theory or its output
is polynomial in that size; we however restrict to the case in which the
original theory has extensions. This study fills a gap between two previous
pieces of work, one studying bijective translations among restrictions of
default logics, and the other one studying non-bijective translations between
default logics variants.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:03:57 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 13:46:43 GMT"
}
] | 2021-04-12T00:00:00 | [
[
"Liberatore",
"Paolo",
""
]
] |
0707.3782 | Andreas Blass | Andreas Blass, Yuri Gurevich, Dean Rosenzweig, and Benjamin Rossman | Interactive Small-Step Algorithms I: Axiomatization | null | Logical Methods in Computer Science, Volume 3, Issue 4 (November
5, 2007) lmcs:1200 | 10.2168/LMCS-3(4:3)2007 | null | cs.LO | null | In earlier work, the Abstract State Machine Thesis -- that arbitrary
algorithms are behaviorally equivalent to abstract state machines -- was
established for several classes of algorithms, including ordinary, interactive,
small-step algorithms. This was accomplished on the basis of axiomatizations of
these classes of algorithms. Here we extend the axiomatization and, in a
companion paper, the proof, to cover interactive small-step algorithms that are
not necessarily ordinary. This means that the algorithms (1) can complete a
step without necessarily waiting for replies to all queries from that step and
(2) can use not only the environment's replies but also the order in which the
replies were received.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:04:26 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Nov 2007 10:56:47 GMT"
}
] | 2015-07-01T00:00:00 | [
[
"Blass",
"Andreas",
""
],
[
"Gurevich",
"Yuri",
""
],
[
"Rosenzweig",
"Dean",
""
],
[
"Rossman",
"Benjamin",
""
]
] |
0707.3783 | Tim Evans | T.S. Evans, A.D.K. Plato | Network Rewiring Models | 12 pages. Longer version of paper accepted as contribution for ECCS07 | Networks and Heterogeneous Media 3 (2008) 221 | null | Imperial/TP/07/TSE/2 | cond-mat.stat-mech | null | Recently we showed that a simple model of network rewiring could be solved
exactly for any time and any parameter value. We also showed that this model
can be recast in terms of several well known models of statistical physics such
as Urn model and the Voter model. We also noted that it has been applied to a
wide range of problems. Here we consider various generalisations of this model
and include some new exact results.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:21:39 GMT"
}
] | 2008-04-17T00:00:00 | [
[
"Evans",
"T. S.",
""
],
[
"Plato",
"A. D. K.",
""
]
] |
0707.3784 | Sam T. Carr | Sam T. Carr, Alexander O. Gogolin, Alexander A. Nersesyan | Interaction induced dimerization in zigzag single wall carbon nanotubes | 8 pages, 5 figures | Phys. Rev. B 76, 245121 (2007) | 10.1103/PhysRevB.76.245121 | null | cond-mat.str-el | null | We derive a low-energy effective model of metallic zigzag carbon nanotubes at
half filling. We show that there are three important features characterizing
the low-energy properties of these systems: the long-range Coulomb interaction,
umklapp scattering and an explicit dimerization generated by interactions. The
ratio of the dimerization induced gap and the Mott gap induced by the umklapp
interactions is dependent on the radius of the nanotube and can drive the
system through a quantum phase transition with SU(2)_1 quantum symmetry. We
consider the physical properties of the phases on either side of this
transition which should be relevant for realistic nanotubes.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:20:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Carr",
"Sam T.",
""
],
[
"Gogolin",
"Alexander O.",
""
],
[
"Nersesyan",
"Alexander A.",
""
]
] |
0707.3785 | Harmen J. Warringa | Kenji Fukushima, Harmen J. Warringa | Color superconducting matter in a magnetic field | 5 pages, 3 figures | Phys.Rev.Lett.100:032007,2008 | 10.1103/PhysRevLett.100.032007 | BNL-NT-07/33; RBRC-679 | hep-ph | null | We investigate the effect of a magnetic field on cold dense three-flavor
quark matter using an effective model with four-Fermi interactions with
electric and color neutrality taken into account. The gap parameters Delta_1,
Delta_2, and Delta_3 representing respectively the predominant pairing between
down and strange (d-s) quarks, strange and up (s-u) quarks, and up and down
(u-d) quarks, show the de Haas-van Alphen effect, i.e. oscillatory behavior as
a function of the modified magnetic field B that can penetrate the color
superconducting medium. Without applying electric and color neutrality we find
Delta_2 \approx Delta_3 >> Delta_1 for 2 e B / mu_q^2, where e is the modified
electromagnetic coupling constant and mu_q is one third of the baryon chemical
potential. Because the average Fermi surface for each pairing is affected by
taking into account neutrality, the gap structure changes drastically in this
case; we find Delta_1 >> Delta_2 \approx Delta_3 for 2 e B > mu_q^2. We point
out that the magnetic fields as strong as presumably existing inside magnetars
might induce significant deviations from the gap structure Delta_1 \approx
Delta_2 \approx Delta_3 at zero magnetic field.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:28:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fukushima",
"Kenji",
""
],
[
"Warringa",
"Harmen J.",
""
]
] |
0707.3786 | Vatche Sahakian | Gregory Minton, Vatche Sahakian | A new mechanism for non-locality from string theory: UV-IR quantum
entanglement and its imprints on the CMB | 40 pages, 15 figures; v2: citations added, minor figure corrections;
v3: minor changes, revised section 3.3 | Phys.Rev.D77:026008,2008 | 10.1103/PhysRevD.77.026008 | null | hep-th astro-ph | null | Puff field theories (PFT) arise as the decoupling limits of D3 branes in a
Melvin universe and exhibit spatially non-local dynamics. Unlike other
realizations of non-locality in string theory, PFTs have full SO(3) rotational
symmetry. In this work, we analyze the strongly coupled regime of a PFT through
gravitational holography. We find a novel mechanism at the heart of the
phenomenon of non-locality: a quantum entanglement of UV and IR dynamics. In
the holographic bulk, this translates to an apparent horizon splitting the
space into two regions - with the UV completion of the PFT sitting at the
horizon. We unravel this intricate UV-IR setting and devise a prescription for
computing correlators that extends the original dictionary of holographic
renormalization group. We then implement a cosmological scenario where PFT
correlators set the initial conditions for primordial fluctuations. We compute
the associated power spectrum of the CMB and find that the scenario allows for
a distinct stringy signature.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:24:32 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 19:28:17 GMT"
},
{
"version": "v3",
"created": "Tue, 8 Jan 2008 03:26:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Minton",
"Gregory",
""
],
[
"Sahakian",
"Vatche",
""
]
] |
0707.3787 | Francisco Jose Herranz | Angel Ballesteros, Osvaldo Civitarese, Francisco J. Herranz and Marta
Reboiro | Effective su_q(2) models and polynomial algebras for fermion-boson
Hamiltonians | 15 pages | Theor. Math. Phys. 13 (2003) 1495-1504 | 10.1023/A:1027301616731 | null | math-ph math.MP quant-ph | null | Schematic su(2)+h3 interaction Hamiltonians, where su(2) plays the role of
the pseudo-spin algebra of fermion operators and h3 is the Heisenberg algebra
for bosons, are shown to be closely related to certain nonlinear models defined
on a single quantum algebra q-su(2) of quasifermions. In particular, q-su(2)
analogues of the Da Providencia-Schutte and extended Lipkin models are
presented. The connection between q and the physical parameters of the
fermion-boson system is analysed, and the integrability properties of the
interaction Hamiltonians are discussed by using polynomial algebras.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:26:22 GMT"
}
] | 2016-01-07T00:00:00 | [
[
"Ballesteros",
"Angel",
""
],
[
"Civitarese",
"Osvaldo",
""
],
[
"Herranz",
"Francisco J.",
""
],
[
"Reboiro",
"Marta",
""
]
] |
0707.3788 | Lorant Sjouwerman | Lorant O. Sjouwerman, Vincent L. Fish, Mark J. Claussen, Ylva M.
Pihlstroem, Laura K. Zschaechner | Excited-state OH Mainline Masers in AU Geminorum and NML Cygni | ApJ Letter, accepted, 4 pages, 2 figures | null | 10.1086/521827 | null | astro-ph | null | Excited-state OH maser emission has previously been reported in the
circumstellar envelopes of only two evolved stars: the Mira star AU Geminorum
and the hypergiant NML Cygni. We present Very Large Array (VLA) observations of
the 1665, 1667, and excited-state 4750 MHz mainline OH transitions in AU Gem
and Expanded Very Large Array (EVLA) observations of the excited-state 6030 and
6035 MHz OH mainline transitions in NML Cyg. We detect masers in both mainline
transitions in AU Gem but no excited-state emission in either star. We conclude
that the excited-state OH emission in AU Gem is either a transient phenomenon
(such as for NML Cyg outlined below), or possibly an artifact in the data, and
that the excited state OH emission in NML Cyg was generated by an episode of
enhanced shock between the stellar mass-loss and an outflow of the Cyg OB2
association. With these single exceptions, it therefore appears that
excited-state OH emission indeed should not be predicted nor observable in
evolved stars as part of their normal structure or evolution.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:27:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sjouwerman",
"Lorant O.",
""
],
[
"Fish",
"Vincent L.",
""
],
[
"Claussen",
"Mark J.",
""
],
[
"Pihlstroem",
"Ylva M.",
""
],
[
"Zschaechner",
"Laura K.",
""
]
] |
0707.3789 | Andreas Blass | Andreas Blass, Yuri Gurevich, Dean Rosenzweig, and Benjamin Rossman | Interactive Small-Step Algorithms II: Abstract State Machines and
the<br> Characterization Theorem | null | Logical Methods in Computer Science, Volume 3, Issue 4 (November
5, 2007) lmcs:1201 | 10.2168/LMCS-3(4:4)2007 | null | cs.LO | null | In earlier work, the Abstract State Machine Thesis -- that arbitrary
algorithms are behaviorally equivalent to abstract state machines -- was
established for several classes of algorithms, including ordinary, interactive,
small-step algorithms. This was accomplished on the basis of axiomatizations of
these classes of algorithms. In Part I (Interactive Small-Step Algorithms I:
Axiomatization), the axiomatization was extended to cover interactive
small-step algorithms that are not necessarily ordinary. This means that the
algorithms (1) can complete a step without necessarily waiting for replies to
all queries from that step and (2) can use not only the environment's replies
but also the order in which the replies were received. In order to prove the
thesis for algorithms of this generality, we extend here the definition of
abstract state machines to incorporate explicit attention to the relative
timing of replies and to the possible absence of replies. We prove the
characterization theorem for extended abstract state machines with respect to
general algorithms as axiomatized in Part I.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:35:46 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Nov 2007 10:59:16 GMT"
}
] | 2015-07-01T00:00:00 | [
[
"Blass",
"Andreas",
""
],
[
"Gurevich",
"Yuri",
""
],
[
"Rosenzweig",
"Dean",
""
],
[
"Rossman",
"Benjamin",
""
]
] |
0707.3790 | Frank Reifler | Frank Reifler and Randall Morris | Conditions for exact equivalence of Kaluza-Klein and Yang-Mills theories | null | null | null | null | gr-qc math-ph math.MP quant-ph | null | Although it is well known that Kaluza-Klein and Yang-Mills theories define
equivalent structures on principal bundles, the general conditions for
equivalence of their Lagrangians have not been explicitly stated. In this paper
we address the conditions for equivalence. The formulation of these conditions
is based on previous work in which the Dirac and Einstein equations were
unified in a tetrad formulation of the Kaluza-Klein model. This Kaluza-Klein
model is derived from mapping a bispinor field to a set of SL(2,R) x U(1) gauge
potentials and a complex scalar field. (A straightforward derivation of this
map using Hestenes' tetrad for the spin connection in a Riemannian space-time
is included in this paper.) Investigation of this Kaluza-Klein model reveals
two general conditions for establishing an exact equivalence between
Kaluza-Klein and Yang-Mills theories. The first condition is that only
horizontal vector fields occur in the Kaluza-Klein Lagrangian. The second is
that the scalar curvature be restricted to a sum over horizontal sectional
curvatures. We conclude that all known fields (including fermion fields) can
then be represented as components of a Kaluza-Klein metric together with scalar
fields.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:43:53 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Reifler",
"Frank",
""
],
[
"Morris",
"Randall",
""
]
] |
0707.3791 | Marco Aurelio Cattacin Kneipp | Marco A.C. Kneipp | BPS Z(N) String Tensions, Sine Law and Casimir Scaling and Integrable
Field Theories | 21 pages, 10 figures. A correction on the title page | Phys.Rev.D76:125010,2007 | 10.1103/PhysRevD.76.125010 | null | hep-th hep-lat hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a Yang-Mills-Higgs theory with spontaneous symmetry breaking of
the gauge group G -> U(1)^r -> C(G), with C(G) being the center of G. We study
two vacua solutions of the theory which produce this symmetry breaking. We show
that for one of these vacua, the theory in the Coulomb phase has the mass
spectrum of particles and monopoles which is exactly the same as the mass
spectrum of particles and solitons of two dimensional affine Toda field theory.
That result holds also for N=4 Super Yang-Mills theories. On the other hand, in
the Higgs phase, we show that for each of the two vacua the ratio of the
tensions of the BPS Z(N) strings satisfy either the Casimir scaling or the sine
law scaling for G=SU(N). These results are extended to other gauge groups: for
the Casimir scaling, the ratios of the tensions are equal to the ratios of the
quadratic Casimir constant of specific representations; for the sine law
scaling, the tensions are proportional to the components of the left
Perron-Frobenius eigenvector of Cartan matrix and the ratios of tensions are
equal to the ratios of the soliton masses of affine Toda field theories.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:21:23 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 16:23:27 GMT"
},
{
"version": "v3",
"created": "Sat, 20 Oct 2007 18:17:31 GMT"
},
{
"version": "v4",
"created": "Wed, 17 Dec 2008 03:02:43 GMT"
}
] | 2008-12-17T00:00:00 | [
[
"Kneipp",
"Marco A. C.",
""
]
] |
0707.3792 | Jason Nordhaus | J. Nordhaus (Univ. of Rochester), E. G. Blackman (Univ. of Rochester) | The Bipolar Engines of post-AGB stars: Transient Dynamos and Common
Envelopes | 8 pages, 4 figures. To appear in Asymmetrical Planetary Nebulae IV.
R. L. M. Corradi, A. Manchado, N. Soker eds - replaced to properly link to
NASA ADS | null | null | null | astro-ph | null | The physical mechanism(s) responsible for transitioning from a spherical
Asymptotic Giant Branch (AGB) star to an asymmetric post-AGB (pAGB) object is
poorly understood. In particular, excess momenta in the outflows of pAGB
objects suggest that a binary may be required to supply an additional source of
energy and angular momentum. The extraction of rotational energy from the
engine is likely fundamental and may be facilitated if a dynamo is operating in
the interior. In this regard, single star magnetic outflow models have been
proposed as mechanisms for producing and shaping PNe, however these models
neglect the back-reaction of the large-scale magnetic field on the flow.
Here we present a transient $\alpha-\Omega$ dynamo operating in the envelope
of an AGB star in (1) an isolated setting and (2) a common envelope in which
the secondary is a low-mass companion in-spiraling in the AGB interior. The
back reaction of the fields on the shear is included and differential rotation
and rotation deplete via turbulent dissipation and Poynting flux. For an
isolated star, the shear must be resupplied in order to sufficiently sustain
the dynamo. We comment on the energy requirements that convection must satisfy
to accomplish this. For the common envelope case, a robust dynamo can result as
the companion provides an additional source of energy and angular momentum.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:53:54 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Dec 2007 15:49:39 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Nordhaus",
"J.",
"",
"Univ. of Rochester"
],
[
"Blackman",
"E. G.",
"",
"Univ. of Rochester"
]
] |
0707.3793 | Michael J. Longo | Michael J. Longo | Evidence for a Preferred Handedness of Spiral Galaxies | 11 pages, 3 figures | null | null | null | astro-ph | null | In this article I study the distribution of spiral galaxies in the Sloan
Digital Sky Survey (SDSS) to investigate whether the universe has an overall
handedness. A preference for spiral galaxies in one sector of the sky to be
left-handed or right-handed spirals would indicate a preferred handedness. The
SDSS data show a strong signal for such an asymmetry with a probability <0.2%.
The asymmetry axis is at (RA,dec) ~(202 deg,25 deg) with an uncertainty ~15
deg. The axis appears to be correlated with that of the quadrupole and octopole
moments in the WMAP microwave sky survey, an unlikely alignment that has been
dubbed "the axis of evil". Our Galaxy is aligned with its spin axis along the
same direction as the majority of the spirals.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 17:56:10 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Longo",
"Michael J.",
""
]
] |
0707.3794 | Mathias Drton | Mathias Drton, Thomas S. Richardson | Binary Models for Marginal Independence | null | Journal of the Royal Statistical Society Series B 2008, Vol. 70,
No. 2, 287-309 | 10.1111/j.1467-9868.2007.00636.x | null | math.ST stat.TH | null | Log-linear models are a classical tool for the analysis of contingency
tables. In particular, the subclass of graphical log-linear models provides a
general framework for modelling conditional independences. However, with the
exception of special structures, marginal independence hypotheses cannot be
accommodated by these traditional models. Focusing on binary variables, we
present a model class that provides a framework for modelling marginal
independences in contingency tables. The approach taken is graphical and draws
on analogies to multivariate Gaussian models for marginal independence. For the
graphical model representation we use bi-directed graphs, which are in the
tradition of path diagrams. We show how the models can be parameterized in a
simple fashion, and how maximum likelihood estimation can be performed using a
version of the Iterated Conditional Fitting algorithm. Finally we consider
combining these models with symmetry restrictions.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:06:02 GMT"
}
] | 2010-03-04T00:00:00 | [
[
"Drton",
"Mathias",
""
],
[
"Richardson",
"Thomas S.",
""
]
] |
0707.3795 | Stacy McGaugh | Stacy S. McGaugh | The halo by halo missing baryon problem | 10 pages, review for IAU Symposium 244, Dark Galaxies & Lost Baryons | null | 10.1017/S1743921307013920 | null | astro-ph | null | The global missing baryon problem - that the sum of observed baryons falls
short of the number expected form BBN - is well known. In addition to this,
there is also a local missing baryon problem that applies to individual dark
matter halos. This halo by halo missing baryon problem is such that the
observed mass fraction of baryons in individual galaxies falls short of the
cosmic baryon fraction. This deficit is a strong function of circular velocity.
I give an empirical estimate of this function, and note the presence of a
critical scale of ~900 km/s therein. I also briefly review Omega_b from BBN,
highlighting the persistent tension between lithium and the CMB, and discuss
some pros and cons of individual galaxies and clusters of galaxies as potential
reservoirs of dark baryons.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:12:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"McGaugh",
"Stacy S.",
""
]
] |
0707.3796 | Andrej I. Panin | A. I. Panin (St.Petersburg State University) | Methods of Modern Differential Geometry in Quantum Chemistry: TD
Theories on Grassmann and Hartree-Fock Manifolds | AMSLaTex, 43 pages, 5 figures | null | null | null | physics.chem-ph math-ph math.MP | null | Hamiltonian and Schrodinger evolution equations on finite-dimensional
projective space are analyzed in detail. Hartree-Fock (HF) manifold is
introduced as a submanifold of many electron projective space of states.
Evolution equations, exact and linearized, on this manifold are studied.
Comparison of matrices of linearized Schrodinger equations on many electron
projective space and on the corresponding HF manifold reveals the appearance in
the HF case a constraining matrix that involves matrix elements of
many-electron Hamiltonian between HF state and double excited determinants.
Character of dependence of transition energies on the matrix elements of
constraining matrix is established by means of perturbation analysis. It is
demonstrated that success of time-dependent HF theory in calculation of
transition energies is mainly due to the wrong behavior of these energies as
functions of matrix elements of constraining matrix as compared with the exact
transition energies
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:05:46 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Panin",
"A. I.",
"",
"St.Petersburg State University"
]
] |
0707.3797 | Igor Moskalenko | Igor V. Moskalenko (Stanford) | Origin and propagation of cosmic rays (some highlights) | 8 pages, 1 figure; invited talk at the 5th Workshop on Science with
the New Generation of High Energy Experiments (Frascati, 18-20 June, 2007),
to appear in Frascati Physics Series | Proc. 5th Workshop on Science with the New Generation of High
Energy Experiments, (Frascati, 18-20 June, 2007), eds. A. Lionetto & A.
Morselli, Frascati Physics Series 45 (2007) 39-47 | null | null | astro-ph | null | The detection of high-energy particles, cosmic rays (CRs), deep inside the
heliosphere implies that there are, at least, three distinctly different stages
in the lifetime of a CR particle: acceleration, propagation in the interstellar
medium (ISM), and propagation in the heliosphere. Gamma rays produced by
interactions of CRs with gas, radiation, and magnetic fields can be used to
study their spectra in different locations. Still, accurate direct measurements
of CR species inside the heliosphere (such as their spectra and abundances) are
extremely important for the understanding of their origin and propagation. In
this paper, an emphasis is made on very recent advances and especially on those
where GLAST and PAMELA observations can lead to further progress in our
understanding of CRs.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:24:43 GMT"
}
] | 2007-12-04T00:00:00 | [
[
"Moskalenko",
"Igor V.",
"",
"Stanford"
]
] |
0707.3798 | Victor Pardo | D. Baldomir, V. Pardo, S. Blanco-Canosa, F. Rivadulla, J. Rivas, A.
Pi\~neiro and J.E. Arias | Pressure-induced metal-insulator transition in MgV_2O_4 | 2 pages, 3 figures, accepted in Physica B (Strongly Correlated
Electron Systems '07) | Physica B 403. 1639 (2008) | 10.1016/j.physb.2007.10.208 | null | cond-mat.str-el | null | On the basis of experimental thermoelectric power results and ab initio
calculations, we propose that a metal-insulator transition takes place at high
pressure (approximately 6 GPa) in MgV_2O_4.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:20:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Baldomir",
"D.",
""
],
[
"Pardo",
"V.",
""
],
[
"Blanco-Canosa",
"S.",
""
],
[
"Rivadulla",
"F.",
""
],
[
"Rivas",
"J.",
""
],
[
"Piñeiro",
"A.",
""
],
[
"Arias",
"J. E.",
""
]
] |
0707.3799 | Michael Finkelberg | Roman Bezrukavnikov and Michael Finkelberg | Equivariant Satake category and Kostant-Whittaker reduction | 31 pages, to appear in Moscow Math J; some typos corrected | null | null | null | math.RT | null | We explain (following V. Drinfeld) how the equivariant derived category of
the affine Grassmannian can be described in terms of coherent sheaves on the
Langlands dual Lie algebra equivariant with respect to the adjoint action, due
to some old results of V. Ginzburg. The global cohomology functor corresponds
under this identification to restricti on to the Kostant slice. We extend this
description to loop rotation equivariant derived category, linking it to
Harish-Chandra bimodules for the Langlands dual Lie algebra, so that the global
cohomology functor corresponds to the quantum Kostant-Whittaker reduction of a
Harish-Chandra bimodule. We derive a conjecture from math.AG/0306413 which
identifies the loop-rotation equivariant homology of the affine Grassmannian
with quantized completed Toda lattice.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:22:59 GMT"
},
{
"version": "v2",
"created": "Mon, 18 Feb 2008 20:18:02 GMT"
}
] | 2008-02-18T00:00:00 | [
[
"Bezrukavnikov",
"Roman",
""
],
[
"Finkelberg",
"Michael",
""
]
] |
0707.3800 | Gregory Moreau | A. Djouadi, G. Moreau | Higgs production at the LHC in warped extra-dimensional models | Latex file, 6 pages, 3 figures. Comments added, Higgs branching
ratios calculated and interference modified | Phys.Lett.B660:67-71,2008 | 10.1016/j.physletb.2007.11.034 | LPT-ORSAY-07-52 | hep-ph | null | The extra-dimensional model in which the bulk geometry is a slice of anti-de
Sitter space is a particularly attractive extension of the Standard Model as it
allows to address the gauge hierarchy problem, as well as the mass hierarchy
prevailing among fermions. However, to allow for the masses of the Kaluza-Klein
excitations of the known particles to be near the Terascale without conflicting
with the high-precision electroweak data, one needs to promote the gauge
symmetry to a left-right structure SU(2)_L x SU(2)_R x U(1) which incorporates
a new quark b', the SU(2)_R doublet partner of the heavy top quark. We show
that this new quark will contribute to the main production process of Higgs
bosons at the LHC: the gluon-gluon fusion mechanism which proceeds through
heavy quark triangular loops. In most of the parameter space in which the
measured values of the heavy t,b quark masses are reproduced, the gg -> Higgs
production cross section is significantly altered, even if the b' quark is too
heavy to be directly accessible, m_b' > ~1TeV. Finally, we briefly discuss the
new Higgs production and decay channels involving the b' quark.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:45:48 GMT"
},
{
"version": "v2",
"created": "Wed, 17 Oct 2007 18:57:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Djouadi",
"A.",
""
],
[
"Moreau",
"G.",
""
]
] |
0707.3801 | Rongwei Yang | Keiji Izuchi and Rongwei Yang | $N_{\p}$-type quotient modules on the torus | null | null | null | null | math.FA | null | Structure of the quotient modules in $\hh$ is very complicated. A good
understanding of some special examples will shed light on the general picture.
This paper studies the so-call $N_{\p}$-type quotient modules, namely, quotient
modules of the form $\hh\ominus [z-\p]$, where $\p (w)$ is a function in the
classical Hardy space $H^2(\G)$ and $[z-\p]$ is the submodule generated by
$z-\p (w)$. This type of quotient modules serve as good examples in many
studies. A notable feature of the $N_{\p}$-type quotient module is its close
connections with some classical single variable operator theories.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 18:51:21 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Izuchi",
"Keiji",
""
],
[
"Yang",
"Rongwei",
""
]
] |
0707.3802 | Jose Vilar | Jose M. G. Vilar and J. Miguel Rubi | Inconsistency of the non-standard definition of work | null | null | null | null | cond-mat.stat-mech cond-mat.soft | null | We show that the recently postulated non-standard definition of work
proportional to force variation rather than to displacement [A. Imparato and L.
Peliti, cond-mat arXiv:0706.1134v1] is thermodynamically inconsistent at both
microscopic and macroscopic scales and leads to non-physical results, including
free energy changes that depend on arbitrary parameters.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:05:38 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Vilar",
"Jose M. G.",
""
],
[
"Rubi",
"J. Miguel",
""
]
] |
0707.3803 | Kurt Jacobs | Kurt Jacobs, Andrew N. Jordan, Elinor K. Irish | Energy Measurements and Preparation of Canonical Phase States of a
Nano-Mechanical Resonator | 4 pages, revtex 4, 3 eps figures. v2: improvements to presentation | Europhys. Lett. 82, 18003 (2008) | null | null | quant-ph cond-mat.mes-hall | null | We show that a continuous quantum non-demolition measurement of the energy of
a nanomechanical resonator can be achieved by monitoring the resonator with a
quantum point contact via a Cooper-pair box. This technique can further be used
to prepare highly non-classical states of two resonators, such as canonical
phase-reference states, and so-called "noon" states.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:23:41 GMT"
},
{
"version": "v2",
"created": "Sun, 21 Oct 2007 00:28:22 GMT"
}
] | 2008-03-17T00:00:00 | [
[
"Jacobs",
"Kurt",
""
],
[
"Jordan",
"Andrew N.",
""
],
[
"Irish",
"Elinor K.",
""
]
] |
0707.3804 | Paulo Tabuada | Paulo Tabuada, Aaron D. Ames, Agung Julius and George J. Pappas | Approximate reduction of dynamical systems | null | null | null | null | math.OC math.DS | null | The reduction of dynamical systems has a rich history, with many important
applications related to stability, control and verification. Reduction of
nonlinear systems is typically performed in an exact manner - as is the case
with mechanical systems with symmetry--which, unfortunately, limits the type of
systems to which it can be applied. The goal of this paper is to consider a
more general form of reduction, termed approximate reduction, in order to
extend the class of systems that can be reduced. Using notions related to
incremental stability, we give conditions on when a dynamical system can be
projected to a lower dimensional space while providing hard bounds on the
induced errors, i.e., when it is behaviorally similar to a dynamical system on
a lower dimensional space. These concepts are illustrated on a series of
examples.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:13:21 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Tabuada",
"Paulo",
""
],
[
"Ames",
"Aaron D.",
""
],
[
"Julius",
"Agung",
""
],
[
"Pappas",
"George J.",
""
]
] |
0707.3805 | Chi-Thiem Hoang | Alex Lazarian, Thiem Hoang | Subsonic Mechanical Alignment of Irregular Grains | 12 pages, 4 figures, typos corrected | Astrophys.J.669:L77-L80,2007 | 10.1086/523849 | null | astro-ph | null | We show that grains can be efficiently aligned by interacting with a subsonic
gaseous flow. The alignment arises from grains having irregularities that
scatter atoms with different efficiency in the right and left directions. The
grains tend to align with long axes perpendicular to magnetic field, which
corresponds to Davis-Greenstein predictions. Choosing conservative estimates,
scattering efficiency of impinging atoms and conservative ``degree of
helicity'', the alignment of helical grains is much more efficient than the
Gold-type alignment processes.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:23:20 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 18:36:20 GMT"
},
{
"version": "v3",
"created": "Wed, 17 Oct 2007 18:57:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lazarian",
"Alex",
""
],
[
"Hoang",
"Thiem",
""
]
] |
0707.3806 | Martin Tajmar | M. Tajmar, F. Plesescu, B. Seifert, R. Schnitzer, I. Vasiljevich | Search for Frame-Dragging-Like Signals Close to Spinning Superconductors | Paper presented at the 18th International Conference on General
Relativity & Gravitation, Sydney, Jul 2007 and at the Time & Matter
Conference, Bled, Sept 2007, GPB Data Corrected and Model Updated | Proceedings of the 2nd International Conference on Time and
Matter, University of Nova Gorica Press, Nova Gorica, 2008, pp. 49-74 | null | null | gr-qc | null | High-resolution accelerometer and laser gyroscope measurements were performed
in the vicinity of spinning rings at cryogenic temperatures. After passing a
critical temperature, which does not coincide with the material's
superconducting temperature, the angular acceleration and angular velocity
applied to the rotating ring could be seen on the sensors although they are
mechanically de-coupled. A parity violation was observed for the laser
gyroscope measurements such that the effect was greatly pronounced in the
clockwise-direction only. The experiments seem to compare well with recent
independent tests obtained by the Canterbury Ring Laser Group and the
Gravity-Probe B satellite. All systematic effects analyzed so far are at least
3 orders of magnitude below the observed phenomenon. The available experimental
data indicates that the fields scale similar to classical frame-dragging
fields. A number of theories that predicted large frame-dragging fields around
spinning superconductors can be ruled out by up to 4 orders of magnitude.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:25:10 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 16:35:53 GMT"
},
{
"version": "v3",
"created": "Fri, 10 Aug 2007 15:54:43 GMT"
},
{
"version": "v4",
"created": "Sat, 25 Aug 2007 10:51:12 GMT"
},
{
"version": "v5",
"created": "Fri, 14 Sep 2007 15:17:13 GMT"
},
{
"version": "v6",
"created": "Tue, 13 Nov 2007 15:37:19 GMT"
},
{
"version": "v7",
"created": "Mon, 19 Nov 2007 12:07:08 GMT"
},
{
"version": "v8",
"created": "Mon, 3 Dec 2007 08:42:20 GMT"
},
{
"version": "v9",
"created": "Tue, 22 Apr 2008 07:09:18 GMT"
}
] | 2008-04-22T00:00:00 | [
[
"Tajmar",
"M.",
""
],
[
"Plesescu",
"F.",
""
],
[
"Seifert",
"B.",
""
],
[
"Schnitzer",
"R.",
""
],
[
"Vasiljevich",
"I.",
""
]
] |
0707.3807 | Catherine Recanati | Catherine Recanati (LIPN) | How to be correct, lazy and efficient ? | 21 pages | null | null | null | cs.PL | null | This paper is an introduction to Lambdix, a lazy Lisp interpreter implemented
at the Research Laboratory of Paris XI University (Laboratoire de Recherche en
Informatique, Orsay). Lambdix was devised in the course of an investigation
into the relationship between the semantics of programming languages and their
implementation; it was used to demonstrate that in the Lisp domain, semantic
correctness is consistent with efficiency, contrary to what has often been
claimed. The first part of the paper is an overview of well-known semantic
difficulties encountered by Lisp as well as an informal presentation of
Lambdix; it is shown that the difficulties which Lisp encouters do not arise in
Lambdix. The second part is about efficiency in implementation models. It
explains why Lambdix is better suited for lazy evaluation than previous models.
The section ends by giving comparative execution time tables.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:33:07 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Recanati",
"Catherine",
"",
"LIPN"
]
] |
0707.3808 | Edward Flagg | A. Muller, E. B. Flagg, P. Bianucci, D. G. Deppe, W. Ma, J. Zhang, G.
J. Salamo, and C. K. Shih | Coherently driven non-classical light emission from a quantum dot | 12 pages, 5 figures, submitted to Nature Photonics | null | null | null | cond-mat.mes-hall | null | Narrow line-widths and the possibility of enhanced spontaneous emission via
coupling to microcavities make semiconductor quantum dots ideal for harnessing
coherent quantum phenomena at the single photon level. So far, however, all
approaches have relied on incoherent pumping, which limits the desirable
properties of the emission. In contrast, coherent excitation was recognized to
be necessary for providing both improved photon indistinguishability and high
efficiency, and offers the quantum control capabilities required for basic
qubit manipulations. Here we achieve, for the first time, resonant and coherent
excitation of a quantum dot with simultaneous collection of the non-classical
photon emission. Second-order correlation measurements show the unique
signature of a coherently-driven two-level quantum emitter: the photon
statistics become oscillatory at high driving fields, reflecting the coherent
evolution of the excitonic ground state of the quantum dot.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:37:21 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Muller",
"A.",
""
],
[
"Flagg",
"E. B.",
""
],
[
"Bianucci",
"P.",
""
],
[
"Deppe",
"D. G.",
""
],
[
"Ma",
"W.",
""
],
[
"Zhang",
"J.",
""
],
[
"Salamo",
"G. J.",
""
],
[
"Shih",
"C. K.",
""
]
] |
0707.3809 | Brice-Olivier Demory | B.-O. Demory (1,7), M. Gillon (1,2), T. Barman (3), X. Bonfils (4), M.
Mayor (1), T. Mazeh (5), D. Queloz (1), S. Udry (1), F. Bouchy (8), X.
Delfosse (6), T. Forveille (6), F. Mallmann (7), F. Pepe (1), C. Perrier (6)
((1) Observatoire de Geneve, Universite de Geneve, Switzerland; (2) Institut
d'Astrophysique et de Geophysique, Universite de Liege, Belgium; (3) Lowell
Observatory, Flagstaff, AZ, USA; (4) Observatorio Astronomico de Lisboa,
Lisboa, Portugal; (5) School of Physics and Astronomy, Raymond and Beverly
Sackler Faculty of Exact Sciences, Tel Aviv University, Israel; (6)
Laboratoire d'Astrophysique de Grenoble, Universite J. Fourier, Grenoble,
France; (7) Observatoire Francois-Xavier Bagnoud - OFXB, Saint-Luc,
Switzerland; (8) Institut d'Astrophysique de Paris, Universite Pierre & Marie
Curie, Paris, France) | Characterization of the hot Neptune GJ 436b with Spitzer and
ground-based observations | Accepted for publication in A&A on 11/09/2007; 7 pages, 6 figures | null | 10.1051/0004-6361:20078354 | null | astro-ph | null | We present Spitzer Space Telescope infrared photometry of a secondary eclipse
of the hot Neptune GJ436b. The observations were obtained using the 8-micron
band of the InfraRed Array Camera (IRAC). The data spanning the predicted time
of secondary eclipse show a clear flux decrement with the expected shape and
duration. The observed eclipse depth of 0.58 mmag allows us to estimate a
blackbody brightness temperature of T_p = 717 +- 35 K at 8 microns. We compare
this infrared flux measurement to a model of the planetary thermal emission,
and show that this model reproduces properly the observed flux decrement. The
timing of the secondary eclipse confirms the non-zero orbital eccentricity of
the planet, while also increasing its precision (e = 0.14 +- 0.01). Additional
new spectroscopic and photometric observations allow us to estimate the
rotational period of the star and to assess the potential presence of another
planet.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:50:43 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 20:31:37 GMT"
},
{
"version": "v3",
"created": "Fri, 14 Sep 2007 14:52:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Demory",
"B. -O.",
""
],
[
"Gillon",
"M.",
""
],
[
"Barman",
"T.",
""
],
[
"Bonfils",
"X.",
""
],
[
"Mayor",
"M.",
""
],
[
"Mazeh",
"T.",
""
],
[
"Queloz",
"D.",
""
],
[
"Udry",
"S.",
""
],
[
"Bouchy",
"F.",
""
],
[
"Delfosse",
"X.",
""
],
[
"Forveille",
"T.",
""
],
[
"Mallmann",
"F.",
""
],
[
"Pepe",
"F.",
""
],
[
"Perrier",
"C.",
""
]
] |
0707.3810 | Mariano Santander | Leonor Garcia-Gutierrez and Mariano Santander | Levi-Civita regularization and geodesic flows for the `curved' Kepler
problem | 19 pages | null | null | null | math-ph math.MP | null | We introduce the regularization Levi-Civita parameter for the `curved
Kepler', i.e., motion under the `Kepler-Coulomb' potential in a configuration
space with any constant curvature and metric of any signature type. Consistent
use of this parameter allows to solve the problem of motion (orbit shape and
time evolution along the orbit), thereby extending the use of the Levi-Civita
parameter beyond the usual Kepler problem in a flat Euclidean configuration
space. A `universal' description, where all relations are applicable to the
motions in any space and with any energy follow from our approach, with no need
to discuss separately the cases where the configuration space is flat or where
energy vanishes.
We also discuss the connection of this `curved Kepler' problem with a
geodesic flow. The well known results by Moser, Osipov and Belbruno are shown
to hold essentially unchanged beyond the flat Euclidean configuration space.
`Curved' Kepler motions with a fixed value of the constant of motion
$\sigma:=-(2E - \kappa_1\kappa_2 J^2)$ on any curved configuration space with
constant curvature $\kappa_1$ and metric of signature type $\kappa_2$ can be
identified with the geodesic flow on a space with curvature $\sigma$ and metric
of the same signature type.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:57:14 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 20:07:04 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Garcia-Gutierrez",
"Leonor",
""
],
[
"Santander",
"Mariano",
""
]
] |
0707.3811 | John Herrick | John Herrick and Aaron Bensimon | Global regulation of genome duplication in eukaryotes: an overview from
the epifluorescence microscope | 57 pages 5 figures fourth version references corrected | null | null | null | q-bio.GN | null | In eukaryotes, DNA replication is initiated along each chromosome at multiple
sites called replication origins. Locally, each replication origin is
"licensed", or specified, at the end of the M and the beginning of G1 phases of
the cell cycle. During S phase when DNA synthesis takes place, origins are
activated in stages corresponding to early and late replicating domains. The
staged and progressive activation of replication origins reflects the need to
maintain a strict balance between the number of active replication forks and
the rate at which DNA synthesis procedes. This suggests that origin densities
(frequency of intiation) and replication fork movement (rates of elongation)
must be co-regulated in order to guarantee the efficient and complete
duplication of each subchromosomal domain. Emerging evidence supports this
proposal and suggests that the ATM/ATR intra-S phase checkpoint plays an
important role in the co-regulation of initiation frequencies and rates of
elongation. In the following, we review recent results concerning the
mechanisms governing the global regulation of DNA replication and discuss the
roles these mechanisms play in maintaining genome stability during both a
normal and perturbed S phase.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 19:59:44 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 21:57:14 GMT"
},
{
"version": "v3",
"created": "Mon, 14 Jan 2008 17:18:34 GMT"
},
{
"version": "v4",
"created": "Mon, 21 Jan 2008 10:03:38 GMT"
}
] | 2008-01-21T00:00:00 | [
[
"Herrick",
"John",
""
],
[
"Bensimon",
"Aaron",
""
]
] |
0707.3812 | Gabriel Vilcu | Stere Ianus, Adrian Mihai Ionescu, Gabriel Eduard Vilcu | Foliations on quaternion CR-submanifolds | 10 pages | Houston Journal of Mathematics, 33 (3) 2008, 739-751 | null | null | math.DG | null | The purpose of this paper is to study the canonical foliations of a
quaternion CR-submanifold of a quaternion K\"{a}hler manifold.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:03:27 GMT"
}
] | 2010-07-15T00:00:00 | [
[
"Ianus",
"Stere",
""
],
[
"Ionescu",
"Adrian Mihai",
""
],
[
"Vilcu",
"Gabriel Eduard",
""
]
] |
0707.3813 | Michael Blanton | Michael R. Blanton, Marla Geha, Andrew A. West | Testing cold dark matter with the low mass Tully-Fisher relation | submitted to ApJ | null | 10.1086/588800 | null | astro-ph | null | The galaxy circular velocity function at small masses is related to the
matter power spectrum on small scales. Although this function is well-studied
for Local Group dwarfs, theoretical predictions and observational measurements
are difficult for satellite galaxies, because of ram pressure and tidal
stripping. By contrast, isolated dwarf galaxies are less affected by these
processes, and almost always have enough 21cm emission to trace their dynamics
robustly. Here, we test cold dark matter cosmology using isolated low mass
dwarf galaxies from the SDSS with measured 21cm widths. We find consistency
between the predicted and observed number density of isolated galaxies down to
circular velocities of 50 km/s. Our technique yields a direct test of
small-scale cosmology independent of the Lyman-alpha forest power spectrum, but
our sample is currently statistically less powerful: warm dark matter particles
heavier than 0.5 keV cannot be ruled out. Our major systematic uncertainty is
the surface brightness limit of the SDSS. Blind HI surveys, such as the ALFALFA
survey on Arecibo, will uncover a larger number of isolated low mass galaxies
and increase the power of our constraints. With our sample, we also find that
the Tully-Fisher relation for dwarf galaxies is a strong function of
environment, and that the baryonic fraction is only a weak function of mass.
These results suggest that for dwarf galaxies, gas loss is dominated by
external, not internal, processes. [abridged]
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:03:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Blanton",
"Michael R.",
""
],
[
"Geha",
"Marla",
""
],
[
"West",
"Andrew A.",
""
]
] |
0707.3814 | Daisuke Kawata | Daisuke Kawata (1,2), John S. Mulchaey (1) ((1) Carnegie
Observatories, (2) Swinburne) | Strangulation in Galaxy Groups | 5 pages, 4 figures, ApJL in press | null | 10.1086/526544 | null | astro-ph | null | We use a cosmological chemodynamical simulation to study how the group
environment impacts the star formation properties of disk galaxies. The
simulated group has a total mass of M~8x10^12 Msun and a total X-ray luminosity
of L_X~10^41 erg s^-1. Our simulation suggests that ram pressure is not
sufficient in this group to remove the cold disk gas from a V_rot~150 km s^-1
galaxy. However, the majority of the hot gas in the galaxy is stripped over a
timescale of approximately 1 Gyr. Since the cooling of the hot gas component
provides a source for new cold gas, the stripping of the hot component
effectively cuts off the supply of cold gas. This in turn leads to a quenching
of star formation. The galaxy maintains the disk component after the cold gas
is consumed, which may lead to a galaxy similar to an S0. Our self-consistent
simulation suggests that this strangulation mechanism works even in low mass
groups, providing an explanation for the lower star formation rates in group
galaxies relative to galaxies in the field.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:06:59 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Nov 2007 02:47:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kawata",
"Daisuke",
""
],
[
"Mulchaey",
"John S.",
""
]
] |
0707.3815 | E. Freeland | E. Freeland and E. Wilcots | Bent-Double Radio Sources as Probes of the Intragroup Medium | 6 pages, 6 figures (some reduced in quality), to appear in
"Extragalactic Jets: Theory and Observation from Radio to Gamma Ray", eds. T.
A. Rector and D. S. De Young, ASP conference series | null | null | null | astro-ph | null | Galaxy groups likely contain a significant fraction of the total baryonic
mass in the local universe within their intragroup medium (IGM). However, aside
from a handful of UV absorption line and X-ray observations, almost nothing is
known about the IGM. We present early results from a research program that
combines low-frequency radio continuum observations and optical spectroscopy of
bent-double radio sources and their neighbors in groups of galaxies. These
observations allow us to probe the density of the IGM to an unprecedented
degree by examining its impact on the jets of radio galaxies.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:11:04 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Freeland",
"E.",
""
],
[
"Wilcots",
"E.",
""
]
] |
0707.3816 | Sherri Honza | L.S. Matthews and T.W. Hyde | Charging of Fractal Dust Agglomerates in a Plasma Environment | null | null | null | CASPER-07-08 | astro-ph | null | The charge on micron-sized dust grains plays a crucial role in the structure
and evolution of forming aggregates within the dust population during the
coagulation process. The manner in which the charge is arranged on developing
irregular structures can affect the fractal dimension of aggregates formed
during collisions, which in turn influences the coagulation rate and size
evolution of the dust cloud. Preliminary models for the charge evolution on
fractal aggregates immersed in a plasma environment calculated using a
modification to the orbital-motion-limited (OML) theory are presented in this
paper. The model calculates currents to each point on the aggregate surface
using a line-of-sight (LOS) approximation: only those electron or ion
trajectories which are not blocked by another grain within the aggregate
contribute to the charging current. Both the total charge and the dipole moment
are calculated for the dust aggregate. While most coagulation theories assume
that it is difficult for like-charged grains to coagulate, the OML_LOS
approximation indicates that the electric potentials of aggregate structures
are often reduced enough to allow significant coagulation.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:15:35 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Matthews",
"L. S.",
""
],
[
"Hyde",
"T. W.",
""
]
] |
0707.3817 | Joseph W. Brill | L. Ladino, E.G. Bittle, M. Uddin, and J.W. Brill | Electro-Optic Search for Critical Divergence of the Charge-Density-Wave
Diffusion Constant at the Onset of Depinning | 9 pages, including 3 figures, submitted to Physical Review B | null | 10.1103/PhysRevB.76.153104 | null | cond-mat.str-el | null | We have used electro-reflectance measurements to study charge-density-wave
(CDW) polarization dynamics at voltages near the CDW depinning onset (Von) in
the quasi-one-dimensional conductor K0.3MoO3 ("blue bronze"). For low voltages,
where the phase-slip rate is low, it is expected that the polarization
relaxation time should be inversely proportional to the CDW diffusion constant,
which is expected to diverge at Von. At T=78 K, we observe saturation of the
relaxation time at low voltages, suggesting that we are in the low phase-slip
limit and allowing us to estimate the non-critical value of the CDW diffusion
constant D=0.02cm2/s, consistent with the measured phason velocity. At other
temperatures, the relaxation time increases with decreasing volage even at the
lowest voltages we could measure. In no case do we observe the expected
"critical speeding up", setting an upper limit on the critical region of (V/Von
-1)crit < 0.06.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:25:44 GMT"
},
{
"version": "v2",
"created": "Sun, 9 Sep 2007 17:04:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ladino",
"L.",
""
],
[
"Bittle",
"E. G.",
""
],
[
"Uddin",
"M.",
""
],
[
"Brill",
"J. W.",
""
]
] |
0707.3818 | Sameer Murthy | Atish Dabholkar and Sameer Murthy | Fundamental Superstrings as Holograms | 46 pages, JHEP style. v2: Comments, references added | JHEP0802:034,2008 | 10.1088/1126-6708/2008/02/034 | null | hep-th | null | The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz
light-cone gauge is viewed as a possible boundary hologram of the near horizon
region of a small black string. For toroidally compactified strings, the
hologram has global symmetries of AdS_3 \times S^{d-1} \times T^{8-d}, (d
=3,..,8), only some of which extend to local conformal symmetries. We construct
the bulk string theory in detail for the particular case of d=3. The symmetries
of the hologram are correctly reproduced from this exact worldsheet description
in the bulk. Moreover, the central charge of the boundary Virasoro algebra
obtained from the bulk agrees with the Wald entropy of the associated small
black holes. This construction provides an exact CFT description of the near
horizon region of small black holes both in Type-II and heterotic string theory
arising from multiply wound fundamental superstrings.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:42:58 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Sep 2007 09:41:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dabholkar",
"Atish",
""
],
[
"Murthy",
"Sameer",
""
]
] |
0707.3819 | Eduardo Castro | Eduardo V. Castro, N. M. R. Peres, J. M. B. Lopes dos Santos, A. H.
Castro Neto, and F. Guinea | Localized states at zigzag edges of bilayer graphene | 4 pages, 5 figures | Phys. Rev. Lett. 100, 026802 (2008) | 10.1103/PhysRevLett.100.026802 | null | cond-mat.mes-hall | null | We report the existence of zero energy surface states localized at zigzag
edges of bilayer graphene. Working within the tight-binding approximation we
derive the analytic solution for the wavefunctions of these peculiar surface
states. It is shown that zero energy edge states in bilayer graphene can be
divided into two families: (i) states living only on a single plane, equivalent
to surface states in monolayer graphene; (ii) states with finite amplitude over
the two layers, with an enhanced penetration into the bulk. The bulk and
surface (edge) electronic structure of bilayer graphene nanoribbons is also
studied, both in the absence and in the presence of a bias voltage between
planes.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:31:59 GMT"
}
] | 2008-01-16T00:00:00 | [
[
"Castro",
"Eduardo V.",
""
],
[
"Peres",
"N. M. R.",
""
],
[
"Santos",
"J. M. B. Lopes dos",
""
],
[
"Neto",
"A. H. Castro",
""
],
[
"Guinea",
"F.",
""
]
] |
0707.3820 | Sherri Honza | K.Qiao and T.W. Hyde | Structure and Vertical Modes in Finite 2D Plasma Crystals | null | null | null | CASPER-07-05 | physics.plasm-ph | null | In this research, formation of finite two-dimensional (2D) plasma crystals
was numerically simulated. The structure was investigated for systems with
various Debye length and it was found there is a transition from a complete
hexagonal structure to a structure with concentric rings on the outer edge and
hexagonal lattice in the interior as the Debye length increases. The vertical
as well as horizontal oscillation modes thermally excited in the 2D dust
coulomb clusters were investigated. The horizontal mode spectra is shown to
agree with published results while the vertical mode spectra obtained from
numerical simulation and analytical method agree with one another. The
frequency of the vertical modes is shown to have a maximum corresponding to the
whole system acting as a solid plane. For low frequency modes, the largest
amplitude particle motion is concentrated in a few inner rings with the outer
rings remaining almost motionless in contrast to the horizontal modes for which
the strongest motion of the particles is concentrated in the inner rings at
high frequencies.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:44:30 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Qiao",
"K.",
""
],
[
"Hyde",
"T. W.",
""
]
] |
0707.3821 | David Feder | Timothy P. Friesen and David L. Feder | One-way quantum computing in optical lattices with many atom addressing | 11 pages, revtex | Phys. Rev. A 78, 032312 (2008) | 10.1103/PhysRevA.78.032312 | null | quant-ph | null | One of the fundamental conditions for one-way quantum computation (1WQC) is
the ability to make sequential measurements on isolated qubits that comprise
the highly entangled resource for 1WQC, the cluster state. This has been a
significant impediment in the implementation of 1WQC with ultracold atoms
confined in optical lattices, because the width of the measuring lasers is
generally much greater than the atomic (qubit) spacing. We demonstrate that
deterministic 1WQC is nevertheless possible, with a polynomial increase in the
number of operations, as long as the center of the beams can be positioned with
high accuracy. Extending the number of cluster atoms, the scheme is also able
to compensate for accidental measurements of an arbitrary number of nearby
qubits.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:49:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Friesen",
"Timothy P.",
""
],
[
"Feder",
"David L.",
""
]
] |
0707.3822 | Evgeny Plekhanov | Adolfo Avella and Ferdinando Mancini | Study of the spin-$\frac32$ Hubbard-Kondo lattice model by means of the
Composite Operator Method | null | Physica B, 378, 311 (2006) | 10.1016/j.physb.2006.01.227 | null | cond-mat.str-el | null | We study the spin-$\frac32$ Hubbard-Kondo lattice model by means of the
Composite Operator Method, after applying a Holstein-Primakov transformation.
The spin and particle dynamics in the ferromagnetic state are calculated by
taking into account strong on-site correlations between electrons and
antiferromagnetic exchange among $\frac32$ spins, together with usual Hund
coupling between electrons and spins.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:50:31 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Avella",
"Adolfo",
""
],
[
"Mancini",
"Ferdinando",
""
]
] |
0707.3823 | Ana V Ramos | A. V. Ramos, M.-J. Guittet, J.-B. Moussy, R. Mattana, C. Deranlot, F.
Petroff, C. Gatel | Room temperature spin filtering in epitaxial cobalt-ferrite tunnel
barriers | 6 pages, 3 figures | null | 10.1063/1.2787880 | null | cond-mat.mtrl-sci | null | We report direct experimental evidence of room temperature spin filtering in
magnetic tunnel junctions (MTJs) containing CoFe2O4 tunnel barriers via
tunneling magnetoresistance (TMR) measurements.
Pt(111)/CoFe2O4(111)/gamma-Al2O3(111)/Co(0001) fully epitaxial MTJs were grown
in order to obtain a high quality system, capable of functioning at room
temperature. Spin polarized transport measurements reveal significant TMR
values of -18% at 2 K and -3% at 290 K. In addition, the TMR ratio follows a
unique bias voltage dependence that has been theoretically predicted to be the
signature of spin filtering in MTJs containing magnetic barriers. CoFe2O4
tunnel barriers therefore provide a model system to investigate spin filtering
in a wide range of temperatures.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 13:37:04 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 12:01:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ramos",
"A. V.",
""
],
[
"Guittet",
"M. -J.",
""
],
[
"Moussy",
"J. -B.",
""
],
[
"Mattana",
"R.",
""
],
[
"Deranlot",
"C.",
""
],
[
"Petroff",
"F.",
""
],
[
"Gatel",
"C.",
""
]
] |
0707.3824 | Jason Jeffries | J. R. Jeffries, N. P. Butch, B. T. Yukich, and M. B. Maple | Competing Ordered Phases in URu2Si2: Hydrostatic Pressure and
Re-substitution | null | null | 10.1103/PhysRevLett.99.217207 | null | cond-mat.str-el | null | A persistent kink in the pressure dependence of the \hidden order" (HO)
transition temperature of URu2-xRexSi2 is observed at a critical pressure Pc=15
kbar for 0 < x < 0.08. In URu2Si2, the kink at Pc is accompanied by the
destruction of superconductivity; a change in the magnitude of a spin
excitation gap, determined from electrical resistivity measurements; and a
complete gapping of a portion of the Fermi surface (FS), inferred from a change
in scattering and the competition between the HO state and superconductivity
for FS fraction.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:54:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jeffries",
"J. R.",
""
],
[
"Butch",
"N. P.",
""
],
[
"Yukich",
"B. T.",
""
],
[
"Maple",
"M. B.",
""
]
] |
0707.3825 | Mukul Kabir | Mukul Kabir, D. G. Kanhere and Abhijit Mookerjee | Emergence of noncollinear magnetic ordering in small magnetic clusters:
Mn$_n$ and As@Mn$_n$ | 10 Pages and 5 Figures | Phys. Rev. B 75, 214433 (2007) | 10.1103/PhysRevB.75.214433 | null | physics.atm-clus | null | Using first-principles density functional calculations, we have studied the
magnetic ordering in pure Mn$_n$ ($n=2-$10, 13, 15, 19) and As@Mn$_n$
($n=1-$10) clusters. Although, for both pure and doped manganese clusters,
there exists many collinear and noncollinear isomers close in energy, the
smaller clusters with $n\leqslant$5 have collinear magnetic ground state and
the emergence of noncollinear ground states is seen for $n\geqslant$6 clusters.
Due to strong $p-d$ hybridization in As@Mn$_n$ clusters, the binding energy is
substantially enhanced and the magnetic moment is reduced compared to the
corresponding pure Mn$_n$ clusters.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:54:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kabir",
"Mukul",
""
],
[
"Kanhere",
"D. G.",
""
],
[
"Mookerjee",
"Abhijit",
""
]
] |
0707.3826 | Chia-Min Lin | Kazunori Kohri, Chia-Min Lin, David H. Lyth | More hilltop inflation models | 12 pages, 25 figures, to appear in JCAP | JCAP0712:004,2007 | 10.1088/1475-7516/2007/12/004 | null | hep-ph astro-ph hep-th | null | Using analytic expressions, we explore the parameter space for hilltop
inflation models with a potential of the form $V_0\pm m^2\phi^2 -a\phi^p$. With
the positive sign and p>2 this converts the original hybrid inflation model
into a hilltop model, allowing the spectral index to agree with the observed
value n=0.95. In some cases the observed value is theoretically favored, while
in others there is only the generic prediction $|n-1|\lsim 1$.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 20:55:02 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 16:56:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kohri",
"Kazunori",
""
],
[
"Lin",
"Chia-Min",
""
],
[
"Lyth",
"David H.",
""
]
] |
0707.3827 | Stefano Ossicini | Federico Iori, Elena Degoli, Rita Magri, Ivan Marri, G. Cantele, D.
Ninno, F. Trani, O. Pulci, Stefano Ossicini | Engineering Silicon Nanocrystals: Theoretical study of the effect of
Codoping with Boron and Phosphorus | 14 pages 19 figures | Physical Review B 76 (2007) | 10.1103/PhysRevB.76.085302 | null | cond-mat.other cond-mat.mtrl-sci | null | We show that the optical and electronic properties of nanocrystalline silicon
can be efficiently tuned using impurity doping. In particular, we give
evidence, by means of ab-initio calculations, that by properly controlling the
doping with either one or two atomic species, a significant modification of
both the absorption and the emission of light can be achieved. We have
considered impurities, either boron or phosphorous (doping) or both (codoping),
located at different substitutional sites of silicon nanocrystals with size
ranging from 1.1 nm to 1.8 nm in diameter. We have found that the codoped
nanocrystals have the lowest impurity formation energies when the two
impurities occupy nearest neighbor sites near the surface. In addition, such
systems present band-edge states localized on the impurities giving rise to a
red-shift of the absorption thresholds with respect to that of undoped
nanocrystals. Our detailed theoretical analysis shows that the creation of an
electron-hole pair due to light absorption determines a geometry distortion
that in turn results in a Stokes shift between adsorption and emission spectra.
In order to give a deeper insight in this effect, in one case we have
calculated the absorption and emission spectra going beyond the single-particle
approach showing the important role played by many-body effects. The entire set
of results we have collected in this work give a strong indication that with
the doping it is possible to tune the optical properties of silicon
nanocrystals.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 13:40:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Iori",
"Federico",
""
],
[
"Degoli",
"Elena",
""
],
[
"Magri",
"Rita",
""
],
[
"Marri",
"Ivan",
""
],
[
"Cantele",
"G.",
""
],
[
"Ninno",
"D.",
""
],
[
"Trani",
"F.",
""
],
[
"Pulci",
"O.",
""
],
[
"Ossicini",
"Stefano",
""
]
] |
0707.3828 | Mukul Kabir | S. Datta, M. Kabir, S. Ganguly, B. Sanyal, T. Saha-Dasgupta, and A.
Mookerjee | Structure, bonding and magnetism in cobalt clusters | 12 pages and 9 figures | Phys. Rev. B 76, 014429 (2007) | 10.1103/PhysRevB.76.014429 | null | physics.atm-clus | null | The structural, electronic and magnetic properties of Co$_n$ clusters
($n=2-$20) have been investigated using density functional theory within the
pseudopotential plane wave method. An unusual hexagonal growth pattern has been
observed in the intermediate size range, $n=15-$20. The cobalt atoms are
ferromagnetically ordered and the calculated magnetic moments are found to be
higher than that of corresponding hcp bulk value, which are in good agreement
with the recent Stern-Gerlach experiments. The average coordination number is
found to dominate over the average bond length to determine the effective
hybridization and consequently the cluster magnetic moment.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 21:10:57 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Datta",
"S.",
""
],
[
"Kabir",
"M.",
""
],
[
"Ganguly",
"S.",
""
],
[
"Sanyal",
"B.",
""
],
[
"Saha-Dasgupta",
"T.",
""
],
[
"Mookerjee",
"A.",
""
]
] |
0707.3829 | Steve Lalley | Steven Lalley, Xinghua Zheng | Occupation Statistics of Critical Branching Random Walks in Two or
Higher Dimensions | null | null | null | null | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Consider a critical nearest neighbor branching random walk on the
$d$-dimensional integer lattice initiated by a single particle at the origin.
Let $G_{n}$ be the event that the branching random walk survives to generation
$n$. We obtain limit theorems conditional on the event $G_{n}$ for a variety of
occupation statistics: (1) Let $V_{n}$ be the maximal number of particles at a
single site at time $n$. If the offspring distribution has finite $\alpha$th
moment for some integer $\alpha\geq 2$, then in dimensions 3 and higher,
$V_n=O_p(n^{1/\alpha})$; and if the offspring distribution has an exponentially
decaying tail, then $V_n=O_p(\log n)$ in dimensions 3 and higher, and
$V_n=O_p((\log n)^2)$ in dimension 2. Furthermore, if the offspring
distribution is non-degenerate then $P(V_n\geq \delta \log n | G_{n})\to 1$ for
some $\delta >0$. (2) Let $M_{n} (j)$ be the number of multiplicity-$j$ sites
in the $n$th generation, that is, sites occupied by exactly $j$ particles. In
dimensions 3 and higher, the random variables $M_{n} (j)/n$ converge jointly to
multiples of an exponential random variable. (3) In dimension 2, the number of
particles at a "typical" site (that is, at the location of a randomly chosen
particle of the $n$th generation) is of order $O_p(\log n)$, and the number of
occupied sites is $O_p(n/\log n)$.
| [
{
"version": "v1",
"created": "Wed, 25 Jul 2007 21:23:22 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Nov 2008 21:32:35 GMT"
},
{
"version": "v3",
"created": "Wed, 7 Apr 2010 16:04:13 GMT"
}
] | 2010-04-08T00:00:00 | [
[
"Lalley",
"Steven",
""
],
[
"Zheng",
"Xinghua",
""
]
] |
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