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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.4430 | John Wilson | John A. Wilson | A negative-U interpretation of the femto-second laser pulse induced
crystallographic expansion of a cuprate HTSC material reported recently by
Gedik et al | 14 pages, 1 figure | null | 10.1088/0953-8984/19/46/466210 | null | cond-mat.supr-con cond-mat.str-el | null | Gedik et al have very recently demonstrated using a pump/probe femto-second
laser technique that the c-axis lattice parameter of LaCuO4+d temporarily
becomes expanded by as much as 2.5% following pulsed laser optical excitation
at 1.55 eV. Access to an out-of-equilibrium metastable excited state is
observed to develop on a time scale of 30 ps. Subsequently the latter state
decays displaying a still longer half-life of just over 300 ps. Observation of
the temperature independence of this laser induced interstate transfer and of
the linear dependence of the production of the metastable population upon the
energy delivered per unit area by the initiating light pulse (beyond a key
threshold fluence) have been interpreted by Gedik et al within the framework of
standard p-to-d, O-to-Cu, charge transfer excitations. By contrast these same
data are reinterpreted here in terms of pumped local pairs, within a negative-U
scenario of cuprate HTSC behaviour long advocated by the current author. The
d8-to-d10 laser-induced augmentation in the negative-U state population
(10CuIII2-) brings marked c-axis expansion by virtue of (i) the local
electrostatic charge imbalance, (ii) the increased antibonding nature of the
electron double-loading d10(p6) configuration created at pair-receptive CuIII
coordination units, and (iii) the layered nature of the cuprate crystal
structure. The new observations are related through to Rohlers striking,
standard crystallographic observations, to the stripe domain formation, and to
previous pump/probe experiments.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 15:19:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wilson",
"John A.",
""
]
] |
0707.4431 | Mathilde Himgi | Emilie Carr\'e (IMNSSA), Emmanuel Cantais, Olivier Darbin, Jean-Pierre
Terrier, Michel Lonjon, Bruno Palmier, Jean-Jacques Risso | Technical aspects of an impact acceleration traumatic brain injury rat
model with potential suitability for both microdialysis and PtiO2 monitoring | null | Journal of Neuroscience Methods 140, 1-2 (2004) 23-8 | 10.1016/j.jneumeth.2004.04.037 | null | q-bio.NC | null | This report describes technical adaptations of a traumatic brain injury (TBI)
model-largely inspired by Marmarou-in order to monitor microdialysis data and
PtiO2 (brain tissue oxygen) before, during and after injury. We particularly
focalize on our model requirements which allows us to re-create some drastic
pathological characteristics experienced by severely head-injured patients:
impact on a closed skull, no ventilation immediately after impact, presence of
diffuse axonal injuries and secondary brain insults from systemic origin...We
notably give priority to minimize anaesthesia duration in order to tend to
banish any neuroprotection. Our new model will henceforth allow a better
understanding of neurochemical and biochemical alterations resulting from
traumatic brain injury, using microdialysis and PtiO2 techniques already
monitored in our Intensive Care Unit. Studies on efficiency and therapeutic
window of neuroprotective pharmacological molecules are now conceivable to
ameliorate severe head-injury treatment.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 15:23:50 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Carré",
"Emilie",
"",
"IMNSSA"
],
[
"Cantais",
"Emmanuel",
""
],
[
"Darbin",
"Olivier",
""
],
[
"Terrier",
"Jean-Pierre",
""
],
[
"Lonjon",
"Michel",
""
],
[
"Palmier",
"Bruno",
""
],
[
"Risso",
"Jean-Jacques",
""
]
] |
0707.4432 | Hashem Zoubi | Hashem Zoubi, and Helmut Ritsch | Bright and dark excitons in an atom--pair filled optical lattice within
a cavity | null | Europhys. Lett. 82, 14001 (2008). | 10.1209/0295-5075/82/14001 | null | quant-ph | null | We study electronic excitations of a degenerate gas of atoms trapped in pairs
in an optical lattice. Local dipole-dipole interactions produce a long lived
antisymmetric and a short lived symmetric superposition of individual atomic
excitations as the lowest internal on-site excitations. Due to the much larger
dipole moment the symmetric states couple efficiently to neighbouring lattice
sites and can be well represented by Frenkel excitons, while the antisymmetric
dark states stay localized. Within a cavity only symmetric states couple to
cavity photons inducing long range interactions to form polaritons. We
calculate their dispersion curves as well as cavity transmission and reflection
spectra to observe them. For a lattice with aspherical sites bright and dark
states get mixed and their relative excitation energies depend on photon
polarizations. The system should allow to study new types of solid state
phenomena in atom filled optical lattices.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 15:27:48 GMT"
}
] | 2009-08-11T00:00:00 | [
[
"Zoubi",
"Hashem",
""
],
[
"Ritsch",
"Helmut",
""
]
] |
0707.4433 | Friedrich W. Hehl | Gerhard W. Bruhn, Friedrich W. Hehl, and Arkadiusz Jadczyk | Comments on ``Spin Connection Resonance in Gravitational General
Relativity'' | 8 pages latex, 1 figure. Corrected several minor misprints | Acta Physica Polonica B, 39 no 1, 2008, pp. 51-58 | null | null | physics.class-ph gr-qc | null | We comment on a recent article of M.W.Evans, Acta Physica Polonica B38 (2007)
2211. We point out that the equations underlying Evans' theory are highly
problematic. Moreover, we demonstrate that the so-called ``spin connection
resonance'', predicted by Evans, cannot be derived from the equation he used.
We provide an exact solution of Evans' corresponding equation and show that is
has definitely no resonance solutions.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:12:40 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 08:38:22 GMT"
}
] | 2014-07-22T00:00:00 | [
[
"Bruhn",
"Gerhard W.",
""
],
[
"Hehl",
"Friedrich W.",
""
],
[
"Jadczyk",
"Arkadiusz",
""
]
] |
0707.4434 | Alicia M. Sintes | Miquel Trias and Alicia M. Sintes | LISA observations of supermassive black holes: parameter estimation
using full post-Newtonian inspiral waveforms | Final version. Accepted for publication in Phys. Rev. D | Phys.Rev.D77:024030,2008 | 10.1103/PhysRevD.77.024030 | null | gr-qc | null | We study parameter estimation of supermassive black hole binary systems in
the final stage of inspiral using the full post-Newtonian gravitational
waveforms. We restrict our analysis to systems in circular orbit with
negligible spins, in the mass range $10^8\Ms-10^5\Ms$, and compare the results
with those arising from the commonly used restricted post-Newtonian
approximation. The conclusions of this work are particularly important with
regard to the astrophysical reach of future LISA measurements. Our analysis
clearly shows that modeling the inspiral with the full post-Newtonian waveform,
not only extends the reach to higher mass systems, but also improves in general
the parameter estimation. In particular, there are remarkable improvements in
angular resolution and distance measurement for systems with a total mass
higher than $5\times10^6\Ms$, as well as a large improvement in the mass
determination.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:38:31 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Nov 2007 13:04:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Trias",
"Miquel",
""
],
[
"Sintes",
"Alicia M.",
""
]
] |
0707.4435 | Vito W. Scarola | V. W. Scarola and S. Das Sarma | Emulating Non-Abelian Topological Matter in Cold Atom Optical Lattices | null | Phys. Rev. A 77, 023612 (2008) | 10.1103/PhysRevA.77.023612 | null | cond-mat.other | null | Certain proposed extended Bose-Hubbard models may exhibit topologically
ordered ground states with excitations obeying non-Abelian braid statistics. A
sufficient tuning of Hubbard parameters could yield excitation braiding rules
allowing implementation of a universal set of topologically protected quantum
gates. We discuss potential difficulties in realizing a model with a proposed
non-Abelian topologically ordered ground state using optical lattices
containing bosonic dipoles. Our direct implementation scheme does not realize
the necessary anisotropic hopping, anisotropic interactions, and low
temperatures.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:17:34 GMT"
},
{
"version": "v2",
"created": "Sat, 12 Apr 2008 21:54:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Scarola",
"V. W.",
""
],
[
"Sarma",
"S. Das",
""
]
] |
0707.4436 | Ernie Croot | Ernie Croot | An application of linear programming duality to discrete Fourier
analysis and additive problems | This is a preliminary draft. Future drafts will have references,
cleaner proofs, and perhaps some applications of the main theorem | null | null | null | math.CO | null | Suppose that f is a function from Z_p -> [0,1] (Z_p is my notation for the
integers mod p, not the p-adics), and suppose that a_1,...,a_k are some places
in Z_p. In some additive number theory applications it would be nice to perturb
f slightly so that Fourier transform f^ vanishes at a_1,...,a_k, while additive
properties are left intact. In the present paper, we show that even if we are
unsuccessful in this, we can at least say something interesting by using the
principle of the separating hyperplane, a basic ingredient in linear
programming duality.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:18:35 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Croot",
"Ernie",
""
]
] |
0707.4437 | Ruslan Metsaev | R. R. Metsaev | Ordinary-derivative formulation of conformal low-spin fields | 58 pages, LaTeX-2e. v3: Results and conclusions of version v2
unchanged. New representations for Lagrangian of conformal fields added.
Appendix C fully rewritten and moved to Sec.6. Discussion of interrelation of
AdS and Weyl gravities added in Sec.6. Lorentz and de Donder like gauges
added. Appendices B,D,F and references added | null | 10.1007/JHEP01(2012)064 | FIAN-TD-2007-10 | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Conformal fields in flat space-time of even dimension greater than or equal
to four are studied. Second-derivative formulation for spin 0,1,2 conformal
bosonic fields and first-derivative formulation for spin 1/2,3/2 conformal
fermionic fields are developed. For the spin 1,3/2,2 conformal fields, we
obtain gauge invariant Lagrangians and the corresponding gauge transformations.
Gauge symmetries are realized by involving Stueckelberg fields and auxiliary
fields. Realization of global conformal boost symmetries is obtained. Modified
Lorentz and de Donder gauge conditions are introduced. Ordinary-derivative
Lagrangian of interacting Weyl gravity in 4d is obtained. In our approach, the
field content of Weyl gravity, in addition to conformal graviton field,
includes one auxiliary rank-2 symmetric tensor field and one Stueckelberg
vector field. With respect to the auxiliary tensor field, the Lagrangian
contains, in addition to other terms, the Pauli-Fierz mass term. Using the
ordinary-derivative Lagrangian of Weyl gravity, we discuss interrelation of
Einstein AdS gravity and Weyl gravity via breaking conformal gauge symmetries.
Also, we demonstrate use of the light-cone gauge for counting on-shell degrees
of freedom in higher-derivative conformal field theories.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:56:04 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 15:46:03 GMT"
},
{
"version": "v3",
"created": "Mon, 14 Nov 2011 18:04:58 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Metsaev",
"R. R.",
""
]
] |
0707.4438 | Luca Del Zanna | F. Rubini, S. Lorusso, L. Del Zanna, and F. Bacciotti | Proper motions of radiative knots in simulations of stellar jets - An
alternative to pulsating inflow conditions | 11 pages, accepted for publication by A&A | null | 10.1051/0004-6361:20077645 | null | astro-ph | null | Elongated jets from young stellar objects typically present a nodular
structure, formed by a chain of bright knots of enhanced emission with
individual proper motions. Though it is generally accepted that internal shocks
play an important role in the formation and dynamics of such structures, their
precise origin and the mechanisms behind the observed proper motions is still a
matter of debate. Our goal is to study numerically the origin, dynamics, and
emission properties of such knots. Axisymmetric simulations are performed with
a shock-capturing code for gas dynamics, allowing for molecular, atomic, and
ionized hydrogen in non-equilibrium concentrations subject to
ionization/recombination processes. Radiative losses in SII lines are computed,
and the resulting synthetic emission maps are compared with observations. We
show that a pattern of regularly spaced internal oblique shocks, characterized
by individual proper motions, is generated by the pressure gradient between the
propagating jet and the time variable external cocoon. In the case of
under-expanded, light jets the resulting emission knots are found to move
downstream with the jet flow, with increasing velocity and decaying brightness
toward the leading bow shock. This suggests that the basic properties of the
knots observed in stellar jets can be reproduced even without invoking ad hoc
pulsating conditions at the jet inlet, though an interplay between the two
scenarios is certainly possible.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:40:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rubini",
"F.",
""
],
[
"Lorusso",
"S.",
""
],
[
"Del Zanna",
"L.",
""
],
[
"Bacciotti",
"F.",
""
]
] |
0707.4439 | Cai-Dian Lu | Yu-Ming Wang and Cai-Dian Lu (IHEP, Beijing) | Weak productions of new charmonium in semi-leptonic decays of B_c | 26 pages, with 7 figures, revTex4 | Phys.Rev.D77:054003,2008 | 10.1103/PhysRevD.77.054003 | null | hep-ph | null | We study the weak productions of novel heavy mesons, such as
$\eta_c^{\prime}$, $h_c$, $h_c^{\prime}$, $\chi_{c0}^{\prime}$, X(3940),
Y(3940), X(3872), and Y(4260), in the semi-leptonic $B_c$ decays. Since there
is still no definite answer for the components of X(3940), Y(3940), X(3872),
Y(4260) so far, we will assign them as excited charmonium states with the
possible quantum numbers constrained by the current experiments. As for the
weak transition form factors, we calculate them in the framework of light-cone
QCD sum rules approach, which is proved to be a powerful tool to deal with the
non-perturbative hadronic matrix element. Our results indicate that different
interpretations of X(3940) can result in remarkable discrepancy of the
production rate in the $B_c$ decays, which would help to clarify the inner
structure of the X(3940) with the forthcoming LHC-b experiments. Besides, the
predicted large weak production rates of X(3872) and Y(3940) in $B_c$ decays
and the small semi-leptonic decay rate for $B_c \to Y(4260)$ all depend on
their quantum number $J^{PC}$ assignments. Moreover, the $S-D$ mixing of
various vector charmonium states in the weak decay of $B_c$ is also discussed
in this work. The future experimental measurements of these decays will test
the inner structures of these particles, according to our predictions here.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:40:53 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Aug 2007 12:31:31 GMT"
},
{
"version": "v3",
"created": "Mon, 10 Mar 2008 13:46:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wang",
"Yu-Ming",
"",
"IHEP, Beijing"
],
[
"Lu",
"Cai-Dian",
"",
"IHEP, Beijing"
]
] |
0707.4440 | Simone Zaggia R. | M. L\'opez-Corredoira (1), Y. Momany (2), S. Zaggia (2), A.
Cabrera-Lavers (1,3) ((1) IAC, (2) INAF-OA Padova, (3) GTC Project Office) | Reaffirming the connection between the Galactic stellar warp and the
Canis Major overdensity | A&A Letter, accepted, 4 pages, 3 figures | null | 10.1051/0004-6361:20077813 | null | astro-ph | null | We perform a critical re-analysis and discussion of recent results presented
in the literature which interpret the CMa overdensity as the signature of an
accreting dwarf galaxy or a new substructure within the Galaxy. Several issues
are addressed. We show that arguments against the ``warp'' interpretation are
based on an erroneous perception of the Milky Way. There is nothing anomalous
with colour--magnitude diagrams on opposite sides of the average warp mid-plane
being different. We witnessed the rise and fall of the blue plume population,
first attributed to young stars in a disrupting dwarf galaxy and now discarded
as a normal disc population. Similarly, there is nothing anomalous in the outer
thin+thick disc metallicities being low (-1<[Fe/H]<-0.5), and spiral arms (as
part of the thin disc) should, and do, warp. Most importantly, we show
unambiguously that, contrary to previous claims, the warp produces a stellar
overdensity that is distance-compatible with that observed in CMa.The CMa
over-density remains fully accounted for in a first order approach by Galactic
models without new substructures. Given the intrinsic uncertainties (concerning
the properties of the warp, flare and disc cutoff, the role of extinction and
degeneracy), minor deviations with respect to these models are not enough to
support the hypothesis of an accreted dwarf galaxy or new substructure within
the Milky Way disc.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:47:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"López-Corredoira",
"M.",
"",
"IAC"
],
[
"Momany",
"Y.",
"",
"INAF-OA Padova"
],
[
"Zaggia",
"S.",
"",
"INAF-OA Padova"
],
[
"Cabrera-Lavers",
"A.",
"",
"IAC",
"GTC Project Office"
]
] |
0707.4441 | Ignacio Franco | Ignacio Franco, Moshe Shapiro and Paul Brumer | Robust ultrafast currents in molecular wires through Stark shifts | 4 pages, 2 figures, accepted to Physical Review Letters | null | 10.1103/PhysRevLett.99.126802 | null | quant-ph | null | A novel way to induce ultrafast currents in molecular wires using two
incident laser frequencies, $\omega$ and $2\omega$, is demonstrated. The
mechanism relies on Stark shifts, instead of photon absorption, to transfer
population to the excited states and exploits the temporal profile of the field
to generate phase controllable transport. Calculations in a
\emph{trans}-polyacetylene oligomer coupled to metallic leads indicate that the
mechanism is highly efficient and robust to ultrafast electronic dephasing
processes induced by vibronic couplings.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:54:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Franco",
"Ignacio",
""
],
[
"Shapiro",
"Moshe",
""
],
[
"Brumer",
"Paul",
""
]
] |
0707.4442 | Wanda Maria Alberico | W.M. Alberico, S. Chiacchiera, H. Hansen, A. Molinari and M. Nardi | Shear Viscosity of Quark Matter | 15 pages, 4 figures | Eur.Phys.J.A38:97-103,2008 | 10.1140/epja/i2008-10648-8 | null | hep-ph | null | We consider the shear viscosity of a system of quarks and its ratio to the
entropy density above the critical temperature for deconfinement. Both
quantities are derived and computed for different modeling of the quark
self-energy, also allowing for a temperature dependence of the effective mass
and width. The behaviour of the viscosity and the entropy density is argued in
terms of the strength of the coupling and of the main characteristics of the
quark self-energy. A comparison with existing results is also discussed.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:54:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Alberico",
"W. M.",
""
],
[
"Chiacchiera",
"S.",
""
],
[
"Hansen",
"H.",
""
],
[
"Molinari",
"A.",
""
],
[
"Nardi",
"M.",
""
]
] |
0707.4443 | Filippo Caruso | Filippo Caruso and Vittorio Giovannetti | Qubit quantum channels: A characteristic function approach | 10 pages (minor editing) | Physical Review A 76, 042331 (2007) | 10.1103/PhysRevA.76.042331 | null | quant-ph cond-mat.other | null | A characterization of qubit quantum channels is introduced. In analogy to
what happens in the context of Bosonic channels we exploit the possibility of
representing the states of the system in terms of characteristic function. The
latter are functions of non-commuting variables (Grassmann variables) and are
defined in terms of generalized displacement operators. In this context we
introduce the set of Gaussian channels and show that they share similar
properties with the corresponding Bosonic counterpart.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:59:08 GMT"
},
{
"version": "v2",
"created": "Thu, 25 Oct 2007 15:40:17 GMT"
}
] | 2007-10-25T00:00:00 | [
[
"Caruso",
"Filippo",
""
],
[
"Giovannetti",
"Vittorio",
""
]
] |
0707.4444 | Thomas Nattermann | T. Nattermann and V.L. Pokrovsky | Bose-Einstein Condensates in Strongly Disordered Traps | null | Phys. Rev. Lett. 100, 060402 (2008) | 10.1103/PhysRevLett.100.060402 | null | cond-mat.stat-mech cond-mat.dis-nn | null | A Bose-Einstein condensate in an external potential consisting of a
superposition of a harmonic and a random potential is considered theoretically.
From a semi-quantitative analysis we find the size, shape and excitation
energy as a function of the disorder strength. For positive scattering length
and sufficiently strong disorder the condensate decays into fragments each of
the size of the Larkin length ${\cal L}$. This state is stable over a large
range of particle numbers. The frequency of the breathing mode scales as
$1/{\cal L}^2$. For negative scattering length a condensate of size ${\cal L}$
may exist as a metastable state. These finding are generalized to anisotropic
traps.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:46:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nattermann",
"T.",
""
],
[
"Pokrovsky",
"V. L.",
""
]
] |
0707.4445 | Seiji Yamamoto | Seiji J. Yamamoto, Qimiao Si | Fermi Surface and Magnetism in the Kondo lattice: A Continuum Field
Theory Approach | 2 pages, 1 embedded eps figure, proceedings of SCES'07 | null | 10.1016/j.physb.2007.10.161 | null | cond-mat.str-el | null | We consider the Fermi surface inside the antiferromagnetic ordered region of
a Kondo lattice system in an arbitrary dimension higher than one. We establish
the existence of ${\rm AF_S}$, an antiferromagnetic phase whose Fermi surface
is ``small,'' in the sense that the local moments do not participate in the
Fermi-surface formation. This is in contrast to the ``large'' Fermi surface
that is typically assumed for heavy fermion metals. We extend our earlier work
to the case that the Fermi surface of the conduction electrons intersects the
antiferromagnetic Brillouin zone boundary. Our results provide a new
perspective on local quantum criticality. In addition, our results imply that,
for the ${\rm AF_S}$ phase, it is important to keep track of the dynamical
screening processes; we suggest that this effect is not captured in a recent
variational Monte-Carlo study of the Kondo lattice.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:06:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yamamoto",
"Seiji J.",
""
],
[
"Si",
"Qimiao",
""
]
] |
0707.4446 | Barbara J. Anthony-Twarog | B. A. Twarog, L. C. Vargas, B. J. Anthony-Twarog (Univ. of Kansas) | The uvbyHbeta Metallicity Calibration for G and K Dwarfs | Latex, 43 pages including 2 tables and 17 figures. Accepted for
Astronomical Journal | Astron.J.134:1777-1789,2007 | 10.1086/522004 | null | astro-ph | null | The metallicity dependence of the primary indices of the uvby photometric
system for cooler dwarfs (Teff ~ 6500 K to 5000K) is investigated. The data
base for the analysis is composed of the overlap between a composite catalog of
selected, high-dispersion spectroscopic abundances for 1801 stars on the
metallicity scale of Valenti and Fischer (2005) and a merged catalog of
high-precision uvbyHbeta photometry for over 35,000 stars. While [Fe/H] for F
dwarfs is best estimated from m_1, with a modest dependence on c_1 as expected,
for hotter G dwarfs the pattern reverses and c_1 becomes the dominant index.
For cooler G dwarfs and K stars, the c_1 dominance continues, but a
discontinuity appears such that stars between (b-y) = 0.50 and 0.58 with [Fe/H]
>= +0.25 have m_1 and c_1 indices that classify them as subgiants, confirming
an earlier result based upon a much smaller sample. The reversal in the
sensitivity to m_1 and c_1 is traced, in part, to the metallicity sensitivity
of the (b-y) index. Moreover, (b-y) grows larger in a non-linear fashion for
stars above solar metallicity, leading to an overestimate of the reddening for
super-metal-rich stars from some standard intrinsic color relations. Based upon
successful tests using indices from synthetic spectra and the empirical trends
among the observations, metallicity calibrations tied to Hbeta rather than
(b-y) have been derived for [Fe/H] >= -1.0, generating dispersions among the
residuals ranging from 0.061 dex to 0.085 dex over the entire temperature range
of interest. The new calibrations have the added advantage of being
significantly less sensitive to errors in reddening than previous calibrations.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:10:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Twarog",
"B. A.",
"",
"Univ. of Kansas"
],
[
"Vargas",
"L. C.",
"",
"Univ. of Kansas"
],
[
"Anthony-Twarog",
"B. J.",
"",
"Univ. of Kansas"
]
] |
0707.4447 | Jaiyeola Temitope Gbolahan | Temitope Gbolahan Jaiyeola, Olushola John Adeniran | On the existence of A-loops with some commutative inner mappings and
others of order 2 | 12 pages. Southeast Asian Bulletin of Mathematics(to appear) | South East Asian Bulletin of Mathematics, Vol. 33 (2009), 853-864. | null | null | math.GM | null | The existence of A$_\rho$-loops, A$_\lambda$-loops and A$_\mu$-loops that are
neither extra loops nor CC-loops such that any two of their inner mappings
$R(x,y),L(x,y)$ and $T(x)$ commute while the other one is of order 2 is shown.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:04:41 GMT"
}
] | 2010-03-09T00:00:00 | [
[
"Jaiyeola",
"Temitope Gbolahan",
""
],
[
"Adeniran",
"Olushola John",
""
]
] |
0707.4448 | Mohamed-Ali Belabbas | Mohamed-Ali Belabbas and Patrick J. Wolfe | On sparse representations of linear operators and the approximation of
matrix products | 6 pages, 3 figures; presented at the 42nd Annual Conference on
Information Sciences and Systems (CISS 2008) | null | 10.1109/CISS.2008.4558532 | null | cs.DS cs.CC | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Thus far, sparse representations have been exploited largely in the context
of robustly estimating functions in a noisy environment from a few
measurements. In this context, the existence of a basis in which the signal
class under consideration is sparse is used to decrease the number of necessary
measurements while controlling the approximation error. In this paper, we
instead focus on applications in numerical analysis, by way of sparse
representations of linear operators with the objective of minimizing the number
of operations needed to perform basic operations (here, multiplication) on
these operators. We represent a linear operator by a sum of rank-one operators,
and show how a sparse representation that guarantees a low approximation error
for the product can be obtained from analyzing an induced quadratic form. This
construction in turn yields new algorithms for computing approximate matrix
products.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:20:23 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Jun 2009 12:04:44 GMT"
}
] | 2009-06-26T00:00:00 | [
[
"Belabbas",
"Mohamed-Ali",
""
],
[
"Wolfe",
"Patrick J.",
""
]
] |
0707.4449 | Laurent Moret-Bailly | Laurent Moret-Bailly | Sur la d\'efinissabilit\'e existentielle de la non-nullit\'e dans les
anneaux | 16 pages, in French. Accepted for publication in Algebra and Number
Theory. Change of title and minor changes in the text, following referee's
suggestions. Report number corrected, hyperlinks added | null | null | IRMAR 07-48 | math.AC math.LO | null | We investigate the rings in which the set of nonzero elements is
positive-existential (i.e. a finite union of projections of "algebraic" sets).
In the case of Noetherian domains, we prove in particular that this condition
is satisfied whenever the ring in question is not local Henselian, while it is
not satisfied for any excellent local Henselian domain which is not a field.
As a byproduct, we obtain an answer to a question of Popescu on strong
approximation for Henselian pairs.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:21:27 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 14:07:41 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Moret-Bailly",
"Laurent",
""
]
] |
0707.4450 | Takayuki Miyadera | Takayuki Miyadera, Hideki Imai | Generalized Landau-Pollak Uncertainty Relation | Simplified the proofs. To be published in Phys.Rev.A | Phys. Rev. A 76, 062108 (2007) | 10.1103/PhysRevA.76.062108 | null | quant-ph | null | The Landau-Pollak uncertainty relation treats a pair of rank one projection
valued measures and imposes a restriction on their probability distributions.
It gives a nontrivial bound for summation of their maximum values. We give a
generalization of this bound (weak version of the Landau-Pollak uncertainty
relation). Our generalization covers a pair of positive operator valued
measures. A nontrivial but slightly weak inequality that can treat an arbitrary
number of positive operator valued measures is also presented.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:21:55 GMT"
},
{
"version": "v2",
"created": "Thu, 25 Oct 2007 15:52:01 GMT"
},
{
"version": "v3",
"created": "Thu, 1 Nov 2007 15:50:05 GMT"
}
] | 2008-10-30T00:00:00 | [
[
"Miyadera",
"Takayuki",
""
],
[
"Imai",
"Hideki",
""
]
] |
0707.4451 | Srikanth Iyengar | Luchezar L. Avramov, Srikanth B. Iyengar, Liana M. Sega | Free resolutions over short local rings | 17 pages; number of minor changes. This article will appear in the
Journal of the London Math. Soc | null | null | null | math.AC | null | The structure of minimal free resolutions of finite modules M over
commutative local rings (R,m,k) with m^3=0 and rank_k(m^2) < rank_k(m/m^2)is
studied. It is proved that over generic R every M has a Koszul syzygy module.
Explicit families of Koszul modules are identified. When R is Gorenstein the
non-Koszul modules are classified. Structure theorems are established for the
graded k-algebra Ext_R(k,k) and its graded module Ext_R(M,k).
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:31:47 GMT"
},
{
"version": "v2",
"created": "Wed, 9 Apr 2008 15:11:00 GMT"
}
] | 2008-04-09T00:00:00 | [
[
"Avramov",
"Luchezar L.",
""
],
[
"Iyengar",
"Srikanth B.",
""
],
[
"Sega",
"Liana M.",
""
]
] |
0707.4452 | Javier Almeida | Javier Almeida, M.A. Martin-Delgado, G. Sierra | Critical Lines and Massive Phases in Quantum Spin Ladders with
Dimerization | 9 pages 10 figures | Phys. Rev. B 77, 094415 (2008) | 10.1103/PhysRevB.77.094415 | null | cond-mat.str-el | null | We determine the existence of critical lines in dimerized quantum spin
ladders in their phase diagram of coupling constants using the finite-size DMRG
algorithm. We consider both staggered and columnar dimerization patterns, and
antiferromagnetic and ferromagnetic inter-leg couplings. The existence of
critical phases depends on the precise combination of these patterns. The
nature of the massive phases separating the critical lines are characterized
with generalized string order parameters that determine their valence bond
solid (VBS) content.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:42:20 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 10:12:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Almeida",
"Javier",
""
],
[
"Martin-Delgado",
"M. A.",
""
],
[
"Sierra",
"G.",
""
]
] |
0707.4453 | Eytan Katzav | E. Katzav, M. Adda-Bedia, M. Ben Amar and A. Boudaoud | Roughness of moving elastic lines - crack and wetting fronts | 15 pages, 6 figures | Phys. Rev. E 76 051601 (2007) | 10.1103/PhysRevE.76.051601 | null | cond-mat.mtrl-sci cond-mat.dis-nn cond-mat.stat-mech | null | We investigate propagating fronts in disordered media that belong to the
universality class of wetting contact lines and planar tensile crack fronts. We
derive from first principles their nonlinear equations of motion, using the
generalized Griffith criterion for crack fronts and three standard mobility
laws for contact lines. Then we study their roughness using the self-consistent
expansion. When neglecting the irreversibility of fracture and wetting
processes, we find a possible dynamic rough phase with a roughness exponent of
$\zeta=1/2$ and a dynamic exponent of z=2. When including the irreversibility,
we conclude that the front propagation can become history dependent, and thus
we consider the value $\zeta=1/2$ as a lower bound for the roughness exponent.
Interestingly, for propagating contact line in wetting, where irreversibility
is weaker than in fracture, the experimental results are close to 0.5, while
for fracture the reported values of 0.55--0.65 are higher.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:34:02 GMT"
}
] | 2008-04-21T00:00:00 | [
[
"Katzav",
"E.",
""
],
[
"Adda-Bedia",
"M.",
""
],
[
"Amar",
"M. Ben",
""
],
[
"Boudaoud",
"A.",
""
]
] |
0707.4454 | Shingo Takeuchi | Konstantinos N. Anagnostopoulos (Natl. Tech. U., Athens), Masanori
Hanada (RIKEN), Jun Nishimura (KEK, SOKENDAI), Shingo Takeuchi (SOKENDAI) | Monte Carlo studies of supersymmetric matrix quantum mechanics with
sixteen supercharges at finite temperature | REVTeX4, 4 pages, 3 figures | Phys.Rev.Lett.100:021601,2008 | 10.1103/PhysRevLett.100.021601 | RIKEN-TH-112 KEK-TH-1165 | hep-th hep-lat | null | We present the first Monte Carlo results for supersymmetric matrix quantum
mechanics with sixteen supercharges at finite temperature. The recently
proposed non-lattice simulation enables us to include the effects of fermionic
matrices in a transparent and reliable manner. The internal energy nicely
interpolates the weak coupling behavior obtained by the high temperature
expansion, and the strong coupling behavior predicted from the dual black hole
geometry. The Polyakov line takes large values even at low temperature
suggesting the absence of a phase transition in sharp contrast to the bosonic
case. These results provide highly non-trivial evidences for the gauge/gravity
duality.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:41:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Anagnostopoulos",
"Konstantinos N.",
"",
"Natl. Tech. U., Athens"
],
[
"Hanada",
"Masanori",
"",
"RIKEN"
],
[
"Nishimura",
"Jun",
"",
"KEK, SOKENDAI"
],
[
"Takeuchi",
"Shingo",
"",
"SOKENDAI"
]
] |
0707.4455 | Gilberto Medeiros Kremer | Luis P. Chimento, Fernando P. Devecchi, Monica Forte and Gilberto M.
Kremer | Phantom cosmologies and fermions | 5 pages, version which was accepted for publication in CQG | Class.Quant.Grav.25:085007,2008 | 10.1088/0264-9381/25/8/085007 | null | gr-qc | null | Form invariance transformations can be used for constructing phantom
cosmologies starting with conventional cosmological models. In this work we
reconsider the scalar field case and extend the discussion to fermionic fields,
where the "phantomization" process exhibits a new class of possible accelerated
regimes. As an application we analyze the cosmological constant group for a
fermionic seed fluid.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:48:33 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Mar 2008 07:13:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chimento",
"Luis P.",
""
],
[
"Devecchi",
"Fernando P.",
""
],
[
"Forte",
"Monica",
""
],
[
"Kremer",
"Gilberto M.",
""
]
] |
0707.4456 | Charles Li | Y. Charles Li | The Poincar\'e Recurrence Problem of Inviscid Incompressible Fluids | null | null | null | null | math.AP math-ph math.DS math.MP physics.flu-dyn | null | Nadirashvili presented a beautiful example showing that the Poincar\'e
recurrence does not occur near a particular solution to the 2D Euler equation
of inviscid incompressible fluids. Unfortunately, Nadirashvili's setup of the
phase space is not appropriate, and details of the proof are missing. This note
fixes that.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:53:28 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Li",
"Y. Charles",
""
]
] |
0707.4457 | Alexander Steppke | P Seidel, C Becker, A Steppke, M Buettner, H Schneidewind, V Grosse, G
Zieger and F Schmidl | Long-time stable HTSC DC-SQUID gradiometers with silicon dioxide
passivation for measurements with superconducting flux transformers | 9 pages, 8 figures, ISEC 2007 | null | 10.1088/0953-2048/20/11/S15 | null | cond-mat.supr-con | null | In applications for high-Tc superconducting DC-SQUIDs such as biomagnetism,
nondestructive evaluation and the relaxation of magnetic nanoparticles, it is
important to maintain reliable sensor performance over an extended time period.
We designed and produced DC-SQUID gradiometers based on YBCO thin films which
are inductively coupled to a flux transformer to achieve a higher sensitivity.
The gradiometers are protected against ambient atmosphere and humidity by SiO2
and amorphous YBCO layers.
The noise properties of the sensor in flip-chip configuration, especially in
unshielded environments, are shown. We present a comparison of TBCCO thin films
on buffered sapphire or LaAlO3 substrates for the flux transformer in shielded
and unshielded environments. We reach a low white field gradient noise of 72
fT/(cm sqrt(Hz)) with the TBCCO on LaAlO3 flux transformer. The electric
properties of the gradiometers (critical current IC, normal state resistance RN
and the transfer function VPhi) were measured over a period of one year and do
not show significant signs of degradation.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:57:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Seidel",
"P",
""
],
[
"Becker",
"C",
""
],
[
"Steppke",
"A",
""
],
[
"Buettner",
"M",
""
],
[
"Schneidewind",
"H",
""
],
[
"Grosse",
"V",
""
],
[
"Zieger",
"G",
""
],
[
"Schmidl",
"F",
""
]
] |
0707.4458 | Charles Li | Y. Charles Li | A Recurrence Theorem on the Solutions to the 2D Euler Equation | null | null | null | null | math.AP math-ph math.DS math.MP physics.flu-dyn | null | In this article, I will prove a recurrence theorem which says that any
$H^s(\mathbb{T}^2)$ (s>2) solution to the 2D Euler equation returns repeatedly
to an arbitrarily small $H^0(\mathbb{T}^2)$ neighborhood.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:58:09 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Li",
"Y. Charles",
""
]
] |
0707.4459 | Charles Li | Y. Charles Li | Segment Description of Turbulence | null | null | null | null | math.AP math-ph math.DS math.MP physics.flu-dyn | null | We propose a segment description for turbulent solutions to evolution
equations in an effort to develop an effective description rather than the
classical Reynolds average. The new description has connections with symbolic
dynamics and shadowing technique. The challenge of future study is how to
effectively implement the description numerically.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:00:49 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Li",
"Y. Charles",
""
]
] |
0707.4460 | Muriel Livernet | Nantel Bergeron, Muriel Livernet (LAGA) | A combinatorial basis for the free Lie algebra of the labelled rooted
trees | 12 pages, uses xypic | J.of Lie Theory {\bf 20} (2010), 3--15 | null | null | math.RA math.CO | null | The pre-Lie operad can be realized as a space T of labelled rooted trees. A
result of F. Chapoton shows that the pre-Lie operad is a free twisted Lie
algebra. That is, the S-module T is obtained as the plethysm of the S-module
Lie with an S-module F. In the context of species, we construct an explicit
basis of F. This allows us to give a new proof of Chapoton's results. Moreover
it permits us to show that F forms a sub nonsymmetric operad of the pre-Lie
operad T.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:58:03 GMT"
}
] | 2010-10-05T00:00:00 | [
[
"Bergeron",
"Nantel",
"",
"LAGA"
],
[
"Livernet",
"Muriel",
"",
"LAGA"
]
] |
0707.4461 | Alimamy Bangura | A. F. Bangura, J. D. Fletcher, A. Carrington, J. Levallois, M.
Nardone, B. Vignolle, P. J. Heard, N. Doiron-Leyraud, D. LeBoeuf, L.
Taillefer, S. Adachi, C. Proust, N. E. Hussey | Shubnikov-de Haas oscillations in YBa_2Cu_4O_8 | v2: Version of paper accepted for publication in Physical Review
Letters. Only minor changes to the text and references | PRL 100, 047004 (2008) | 10.1103/PhysRevLett.100.047004 | null | cond-mat.supr-con cond-mat.str-el | null | We report the observation of Shubnikov-de Haas oscillations in the underdoped
cuprate superconductor YBa$_2$Cu$_4$O$_8$ (Y124). For field aligned along the
c-axis, the frequency of the oscillations is $660\pm 30$ T, which corresponds
to $\sim 2.4$ % of the total area of the first Brillouin zone. The effective
mass of the quasiparticles on this orbit is measured to be $2.7\pm0.3$ times
the free electron mass. Both the frequency and mass are comparable to those
recently observed for ortho-II YBa$_2$Cu$_3$O$_{6.5}$ (Y123-II). We show that
although small Fermi surface pockets may be expected from band structure
calculations in Y123-II, no such pockets are predicted for Y124. Our results
therefore imply that these small pockets are a generic feature of the copper
oxide plane in underdoped cuprates.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:10:10 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Dec 2007 18:10:08 GMT"
}
] | 2008-02-04T00:00:00 | [
[
"Bangura",
"A. F.",
""
],
[
"Fletcher",
"J. D.",
""
],
[
"Carrington",
"A.",
""
],
[
"Levallois",
"J.",
""
],
[
"Nardone",
"M.",
""
],
[
"Vignolle",
"B.",
""
],
[
"Heard",
"P. J.",
""
],
[
"Doiron-Leyraud",
"N.",
""
],
[
"LeBoeuf",
"D.",
""
],
[
"Taillefer",
"L.",
""
],
[
"Adachi",
"S.",
""
],
[
"Proust",
"C.",
""
],
[
"Hussey",
"N. E.",
""
]
] |
0707.4462 | Pedro Assis | P. Assis, G. Agnetta, P. Brogueira, O. Catalano, G. Cusumano, N.
Galli, S. Giarrusso, G. la Rosa, M. Pimenta, G. Pires, F. Russo, B. Sacco | Gamma Air Watch (GAW): the electronics and trigger concept | 30th International Cosmic Ray Conference, Merida, Mexico | null | null | null | astro-ph | null | GAW proposes a new approach for the detection and measurement of the
Cherenkov light produced by GeV/TeV gamma rays traversing the Earth atmosphere
which imposes specific requirements on the electronics design. The focal
surface of the GAW telescope consists of a matrix of multi-anode
photomultipliers. The large number of active channels (of the order of 10^5)
makes it basically a large UV sensitive digital camera with high resolution
imaging capability. The limited amount of space available, due to the large
number of channels, requires a compact design with minimal distance between the
elements of the focal surface. The front-end electronics uses the single
photoelectron counting technique to capture the Cherenkov light. The data
acquisition is based on free-running data taking method. Self-triggering
capability for each telescope is assured by detecting an excess of active
pixels, in a 10ns time frame, inside overlapping trigger areas covering the
whole focal surface. In this paper we describe the GAW electronics, as well as
the trigger concept and implementation.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:03:32 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Assis",
"P.",
""
],
[
"Agnetta",
"G.",
""
],
[
"Brogueira",
"P.",
""
],
[
"Catalano",
"O.",
""
],
[
"Cusumano",
"G.",
""
],
[
"Galli",
"N.",
""
],
[
"Giarrusso",
"S.",
""
],
[
"la Rosa",
"G.",
""
],
[
"Pimenta",
"M.",
""
],
[
"Pires",
"G.",
""
],
[
"Russo",
"F.",
""
],
[
"Sacco",
"B.",
""
]
] |
0707.4463 | Mario Pimenta | S. Andringa, M. Pato and M. Pimenta (for the Pierre Auger
Collaboration) | 3D Reconstruction of Extensive Air Showers from Fluorescence Data | 4 pages, 2 figures, presented at ICRC07 | null | null | null | astro-ph | null | A new method to reconstruct the 3-dimensional structure of extensive air
showers, seen by fluorescence detectors, is proposed. The observation of the
shower is done in 2-dimensional pixels, for consecutive time bins. Time
corresponds to a third dimension. Assuming that the cosmic ray shower
propagates as a plane wave front moving at the speed of light, a complex 3D
volume in space can be associated to each measured charge (per pixel and time
bin). The 3D description in space allows a simultaneous access to the
longitudinal and lateral profiles of each shower. In the case that several eyes
observe the same shower, the method gives a straight-forward combination of all
the information. This method is in an early phase of development and is not
used for the general reconstruction of the Auger data.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:05:38 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Andringa",
"S.",
"",
"for the Pierre Auger\n Collaboration"
],
[
"Pato",
"M.",
"",
"for the Pierre Auger\n Collaboration"
],
[
"Pimenta",
"M.",
"",
"for the Pierre Auger\n Collaboration"
]
] |
0707.4464 | Vincenzo Cirigliano | Vincenzo Cirigliano and Ignasi Rosell | pi/K -> e nu branching ratios to O(e^2 p^4) in Chiral Perturbation
Theory | 40 pages, 4 figures, 3 tables | JHEP 0710:005,2007 | 10.1088/1126-6708/2007/10/005 | LAUR-07-4532 | hep-ph | null | We calculate the ratios R_{e/mu}^{(P)} = Gamma(P -> e nu)/Gamma (P -> mu nu)
(P=pi,K) in Chiral Perturbation Theory to order e^2 p^4. We complement the one-
and two-loop effective theory results with a matching calculation of the local
counterterm, performed within the large-$N_C$ expansion. We find
R_{e/mu}^{(\pi)} = (1.2352 \pm 0.0001)*10^{-4} and R_{e/mu}^{(K)} = (2.477 \pm
0.001)*10^{-5}, with uncertainty induced by the matching procedure and chiral
power counting. Given the sensitivity of upcoming new measurements, our results
provide a clean baseline to detect or constrain effects from weak-scale new
physics in these rare decays. As a by-product, we also update the theoretical
analysis of the individual pi/K -> \ell nu modes.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:24:48 GMT"
}
] | 2009-02-18T00:00:00 | [
[
"Cirigliano",
"Vincenzo",
""
],
[
"Rosell",
"Ignasi",
""
]
] |
0707.4465 | Manuel Asorey | M. Asorey, J.F. Carinena, G. Marmo and A. Perelomov | Isoperiodic classical systems and their quantum counterparts | 29 pages, 8 eps figures | AnnalsPhys.322:1444-1465,2007 | 10.1016/j.aop.2006.07.003 | null | hep-th | null | One-dimensional isoperiodic classical systems have been first analyzed by
Abel. Abel's characterization can be extended for singular potentials and
potentials which are not defined on the whole real line. The standard shear
equivalence of isoperiodic potentials can also be extended by using reflection
and inversion transformations. We provide a full characterization of
isoperiodic rational potentials showing that they are connected by
translations, reflections or Joukowski transformations. Upon quantization many
of these isoperiodic systems fail to exhibit identical quantum energy spectra.
This anomaly occurs at order O(h^2) because semiclassical corrections of energy
levels of order O(h) are identical for all isoperiodic systems. We analyze
families of systems where this quantum anomaly occurs and some special systems
where the spectral identity is preserved by quantization. Conversely, we point
out the existence of isospectral quantum systems which do not correspond to
isoperiodic classical systems.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:33:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Asorey",
"M.",
""
],
[
"Carinena",
"J. F.",
""
],
[
"Marmo",
"G.",
""
],
[
"Perelomov",
"A.",
""
]
] |
0707.4466 | Paul Tupper | Benoit Charbonneau, Yuriy Svyrydov, and P.F. Tupper | Weak Convergence in the Prokhorov Metric of Methods for Stochastic
Differential Equations | 12 pages, 2nd revision for IMA J Numerical Analysis. Further minor
errors corrected | null | 10.1093/imanum/drn067 | null | math.NA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the weak convergence of numerical methods for stochastic
differential equations (SDEs). Weak convergence is usually expressed in terms
of the convergence of expected values of test functions of the trajectories.
Here we present an alternative formulation of weak convergence in terms of the
well-known Prokhorov metric on spaces of random variables. For a general class
of methods, we establish bounds on the rates of convergence in terms of the
Prokhorov metric. In doing so, we revisit the original proofs of weak
convergence and show explicitly how the bounds on the error depend on the
smoothness of the test functions. As an application of our result, we use the
Strassen - Dudley theorem to show that the numerical approximation and the true
solution to the system of SDEs can be re-embedded in a probability space in
such a way that the method converges there in a strong sense. One corollary of
this last result is that the method converges in the Wasserstein distance,
another metric on spaces of random variables. Another corollary establishes
rates of convergence for expected values of test functions assuming only local
Lipschitz continuity. We conclude with a review of the existing results for
pathwise convergence of weakly converging methods and the corresponding strong
results available under re-embedding.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:34:48 GMT"
},
{
"version": "v2",
"created": "Thu, 31 Jan 2008 19:56:29 GMT"
},
{
"version": "v3",
"created": "Mon, 20 Oct 2008 04:21:52 GMT"
}
] | 2009-11-28T00:00:00 | [
[
"Charbonneau",
"Benoit",
""
],
[
"Svyrydov",
"Yuriy",
""
],
[
"Tupper",
"P. F.",
""
]
] |
0707.4467 | Mario Pimenta | S. Andringa, P. Assis, M. Pimenta, A. Pina, B. Tome | Gamma/hadron separation in IACTs using 3D EAS variables | 30th International Cosmic Ray Conference 2007, Merida, Mexico | null | null | null | astro-ph | null | A new approach to Gamma/Hadron separation algorithms is proposed. The
differences between Gamma and Hadron showers are notorious in two main aspects.
The first is the wideness of the shower, and the second is the distribution of
the angles of emission of Cherenkov photons in respect to the shower main axis.
Using more than one IAC telescope, and their respective bi-dimensional images
of arrival directions of the Cherenkov photons, the 3D geometrical
characteristics of the shower can be reconstructed.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:54:01 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Andringa",
"S.",
""
],
[
"Assis",
"P.",
""
],
[
"Pimenta",
"M.",
""
],
[
"Pina",
"A.",
""
],
[
"Tome",
"B.",
""
]
] |
0707.4468 | N. Carella A. | N. A. Carella | Note Integer Factoring Methods III | 20 Pages | null | null | null | math.NT math.GM | null | The best deterministic unconditionally proven integer factorization
algorithms have exponential running time complexities of O(N^(1/4)) arithmetic
operations, and conditional on the Riemann hypothesis, there is a deterministic
algorithm of exponential running time complexity O(N^(1/5)). This note proposes
a new deterministic integer factorization algorithm of deterministic
exponential time complexity O(N^(1/6)). Furthermore, an algorithm for
decomposing composite integers that have factor differences of the form q - p =
(r - 1)N^(1/2) + u, where r > 1 is a fixed parameter, and | u | < N^(1/3), in
deterministic logarithmic time and various other results are included.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:55:27 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Carella",
"N. A.",
""
]
] |
0707.4469 | Nicolai Krylov | Naresh Jain, Nicolai Krylov | Large deviations for occupation times of Markov processes with
$L_{\mathbf{2}}$ semigroups | Published in at http://dx.doi.org/10.1214/07-AOP371 the Annals of
Probability (http://www.imstat.org/aop/) by the Institute of Mathematical
Statistics (http://www.imstat.org) | Annals of Probability 2008, Vol. 36, No. 5, 1611-1641 | 10.1214/07-AOP371 | IMS-AOP-AOP371 | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Our aim is to unify and extend the large deviation upper and lower bounds for
the occupation times of a Markov process with $L_2$ semigroups under minimal
conditions on the state space and the process trajectories; for example, no
strong Markov property is needed. The methods used here apply in both
continuous and discrete time. We present the proofs for continuous time only
because of the inherent technical difficulties in that situation; the proofs
can be adapted for discrete time in a straightforward manner.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:15:24 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Sep 2008 05:29:46 GMT"
}
] | 2008-09-24T00:00:00 | [
[
"Jain",
"Naresh",
""
],
[
"Krylov",
"Nicolai",
""
]
] |
0707.4470 | Ari Stern | Ari Stern, Yiying Tong, Mathieu Desbrun, Jerrold E. Marsden | Geometric Computational Electrodynamics with Variational Integrators and
Discrete Differential Forms | 37 pages, 12 figures. v3: broadly revised, including incorporation of
free source terms, new numerical experiments and figures | Geometry, mechanics, and dynamics, vol. 73 of Fields Institute
Communications, 437-475, 2015 | 10.1007/978-1-4939-2441-7_19 | null | math.NA physics.comp-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we develop a structure-preserving discretization of the
Lagrangian framework for electromagnetism, combining techniques from
variational integrators and discrete differential forms. This leads to a
general family of variational, multisymplectic numerical methods for solving
Maxwell's equations that automatically preserve key symmetries and invariants.
In doing so, we demonstrate several new results, which apply both to some
well-established numerical methods and to new methods introduced here. First,
we show that Yee's finite-difference time-domain (FDTD) scheme, along with a
number of related methods, are multisymplectic and derive from a discrete
Lagrangian variational principle. Second, we generalize the Yee scheme to
unstructured meshes, not just in space but in 4-dimensional spacetime. This
relaxes the need to take uniform time steps, or even to have a preferred time
coordinate at all. Finally, as an example of the type of methods that can be
developed within this general framework, we introduce a new asynchronous
variational integrator (AVI) for solving Maxwell's equations. These results are
illustrated with some prototype simulations that show excellent energy and
conservation behavior and lack of spurious modes, even for an irregular mesh
with asynchronous time stepping.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:38:41 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 20:11:34 GMT"
},
{
"version": "v3",
"created": "Wed, 27 May 2009 06:07:50 GMT"
}
] | 2015-11-05T00:00:00 | [
[
"Stern",
"Ari",
""
],
[
"Tong",
"Yiying",
""
],
[
"Desbrun",
"Mathieu",
""
],
[
"Marsden",
"Jerrold E.",
""
]
] |
0707.4471 | Orest Hrycyna | Orest Hrycyna, Marek Szydlowski | Extended Quintessence with non-minimally coupled phantom scalar field | revtex4, 15 pages, 9 figures; (v2) published version | Phys.Rev.D76:123510,2007 | 10.1103/PhysRevD.76.123510 | null | hep-th astro-ph | null | We investigate evolutional paths of an extended quintessence with a
non-minimally coupled phantom scalar field $\psi$ to the Ricci curvature. The
dynamical system methods are used to investigate typical regimes of dynamics at
the late time. We demonstrate that there are two generic types of evolutional
scenarios which approach the attractor (a focus or a node type critical point)
in the phase space: the quasi-oscillatory and monotonic trajectories approach
to the attractor which represents the FRW model with the cosmological constant.
We demonstrate that dynamical system admits invariant two-dimensional
submanifold and discussion that which cosmological scenario is realized depends
on behavior of the system on the phase plane $(\psi, \psi')$. We formulate
simple conditions on the value of coupling constant $\xi$ for which
trajectories tend to the focus in the phase plane and hence damping
oscillations around the mysterious value $w=-1$. We describe this condition in
terms of slow-roll parameters calculated at the critical point. We discover
that the generic trajectories in the focus-attractor scenario come from the
unstable node. It is also investigated the exact form of the parametrization of
the equation of state parameter $w(z)$ (directly determined from dynamics)
which assumes a different form for both scenarios.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:43:27 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Dec 2007 17:47:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hrycyna",
"Orest",
""
],
[
"Szydlowski",
"Marek",
""
]
] |
0707.4472 | Yuji Okawa | Michael Kiermaier (MIT) and Yuji Okawa (DESY) | Exact marginality in open string field theory: a general framework | 63 pages, 10 figures, LaTeX2e | JHEP 0911:041,2009 | 10.1088/1126-6708/2009/11/041 | DESY 07-110, MIT-CTP-3851 | hep-th | null | We construct analytic solutions of open bosonic string field theory for any
exactly marginal deformation in any boundary conformal field theory when
properly renormalized operator products of the marginal operator are given. We
explicitly provide such renormalized operator products for a class of marginal
deformations which include the deformations of flat D-branes in flat
backgrounds by constant massless modes of the gauge field and of the scalar
fields on the D-branes, the cosine potential for a space-like coordinate, and
the hyperbolic cosine potential for the time-like coordinate. In our
construction we use integrated vertex operators, which are closely related to
finite deformations in boundary conformal field theory, while previous analytic
solutions were based on unintegrated vertex operators. We also introduce a
modified star product to formulate string field theory around the deformed
background.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 18:11:29 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Kiermaier",
"Michael",
"",
"MIT"
],
[
"Okawa",
"Yuji",
"",
"DESY"
]
] |
0707.4473 | Kevin Covey | Kevin R. Covey (1), Zeljko Ivezic (2), David J. Schlegel (3), Douglas
P. Finkbeiner (1), Nikhil Padmanabhan (3), Robert H. Lupton (4), Marcel A.
Agueros (5), John J. Bochanski (2), Suzanne L. Hawley (2), Andrew A. West
(6), Anil C. Seth (1), Amy E. Kimball (2), Stephanie M. Gogarten (2), Mark
Claire (2), Daryl Haggard (2), Nathan A. Kaib (2), Donald P. Schneider (7),
Branimir Sesar (2) ((1) Harvard Smithsonian Center for Astrophysics, (2)
University of Washington, (3) Lawrence Berkeley National Laboratory, (4)
Princeton University Observatory, (5) Columbia University, (6) Univeristy of
California Berkeley, (7) Penn State) | Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and
Searching for Color Outliers in SDSS and 2MASS | 23 pages in emulateapj format, 17 figures, 7 tables. Accepted for
publication in the Astronomical Journal. To access a high-resolution version
of this paper, as well as machine readable tables and an archive of 'The
Hammer' spectral typing suite, see http://www.cfa.harvard.edu/~kcovey v2 --
fixed typos in Table 7 (mainly affecting lines for M8-M10 III stars) | Astron.J.134:2398-2417,2007 | 10.1086/522052 | null | astro-ph | null | The Sloan Digital Sky Survey (SDSS) and Two Micron All Sky Survey (2MASS) are
rich resources for studying stellar astrophysics and the structure and
formation history of the Galaxy. As new surveys and instruments adopt similar
filter sets, it is increasingly important to understand the properties of the
ugrizJHKs stellar locus, both to inform studies of `normal' main sequence stars
as well as for robust searches for point sources with unusual colors. Using a
sample of ~600,000 point sources detected by SDSS and 2MASS, we tabulate the
position and width of the ugrizJHKs stellar locus as a function of g-i color,
and provide accurate polynomial fits. We map the Morgan-Keenan spectral type
sequence to the median stellar locus by using synthetic photometry of spectral
standards and by analyzing 3000 SDSS stellar spectra with a custom spectral
typing pipeline. We develop an algorithm to calculate a point source's minimum
separation from the stellar locus in a seven-dimensional color space, and use
it to robustly identify objects with unusual colors, as well as spurious
SDSS/2MASS matches. Analysis of a final catalog of 2117 color outliers
identifies 370 white-dwarf/M dwarf (WDMD) pairs, 93 QSOs, and 90 M giant/carbon
star candidates, and demonstrates that WDMD pairs and QSOs can be distinguished
on the basis of their J-Ks and r-z colors. We also identify a group of objects
with correlated offsets in the u-g vs. g-r and g-r vs. r-i color-color spaces,
but subsequent follow-up is required to reveal the nature of these objects.
Future applications of this algorithm to a matched SDSS-UKIDSS catalog may well
identify additional classes of objects with unusual colors by probing new areas
of color-magnitude space.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 15:53:03 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Sep 2007 05:28:46 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Covey",
"Kevin R.",
""
],
[
"Ivezic",
"Zeljko",
""
],
[
"Schlegel",
"David J.",
""
],
[
"Finkbeiner",
"Douglas P.",
""
],
[
"Padmanabhan",
"Nikhil",
""
],
[
"Lupton",
"Robert H.",
""
],
[
"Agueros",
"Marcel A.",
""
],
[
"Bochanski",
"John J.",
""
],
[
"Hawley",
"Suzanne L.",
""
],
[
"West",
"Andrew A.",
""
],
[
"Seth",
"Anil C.",
""
],
[
"Kimball",
"Amy E.",
""
],
[
"Gogarten",
"Stephanie M.",
""
],
[
"Claire",
"Mark",
""
],
[
"Haggard",
"Daryl",
""
],
[
"Kaib",
"Nathan A.",
""
],
[
"Schneider",
"Donald P.",
""
],
[
"Sesar",
"Branimir",
""
]
] |
0707.4474 | Bernd Rosenow | B. Rosenow, B.I. Halperin, S.H. Simon, and Ady Stern | Bulk-edge coupling in the non-abelian $\nu=5/2$ quantum Hall
interferometer | 5 pages, 1 figure | null | 10.1103/PhysRevLett.100.226803 | null | cond-mat.mes-hall | null | Recent schemes for experimentally probing non-abelian statistics in the
quantum Hall effect are based on geometries where current-carrying
quasiparticles flow along edges that encircle bulk quasiparticles, which are
localized. Here we consider one such scheme, the Fabry-Perot interferometer,
and analyze how its interference patterns are affected by a coupling that
allows tunneling of neutral Majorana fermions between the bulk and edge. While
at weak coupling this tunneling degrades the interference signal, we find that
at strong coupling, the bulk quasiparticle becomes essentially absorbed by the
edge and the intereference signal is fully restored.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:14:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rosenow",
"B.",
""
],
[
"Halperin",
"B. I.",
""
],
[
"Simon",
"S. H.",
""
],
[
"Stern",
"Ady",
""
]
] |
0707.4475 | Yuriy Pershin | Yu. V. Pershin and M. Di Ventra | Current-voltage characteristics of semiconductor/ferromagnet junctions
in the spin blockade regime | null | Phys. Rev. B 77, 073301 (2008) | 10.1103/PhysRevB.77.073301 | null | cond-mat.mes-hall | null | It was recently predicted [Phys. Rev. B 75, 193301 (2007)] that spin blockade
may develop at nonmagnetic semiconductor/perfect ferromagnet junctions when the
electron flow is directed from the semiconductor into the ferromagnet. Here we
consider current-voltage characteristics of such junctions. By taking into
account the contact resistance, we demonstrate a current stabilization effect:
by increasing the applied voltage the current density through the junction
saturates at a specific value. The transient behavior of the current density is
also investigated.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:03:58 GMT"
}
] | 2008-03-23T00:00:00 | [
[
"Pershin",
"Yu. V.",
""
],
[
"Di Ventra",
"M.",
""
]
] |
0707.4476 | Massimo Blasone Dr | Massimo Blasone, Fabio Dell'Anno, Silvio De Siena, Fabrizio Illuminati | Entanglement in neutrino oscillations | 5 pages, 5 figures | Europhys. Lett. 85, 50002 (2009) | 10.1209/0295-5075/85/50002 | null | hep-ph astro-ph hep-th math-ph math.MP quant-ph | http://creativecommons.org/licenses/publicdomain/ | Flavor oscillations in elementary particle physics are related to multi-mode
entanglement of single-particle states. We show that mode entanglement can be
expressed in terms of flavor transition probabilities, and therefore that
single-particle entangled states acquire a precise operational characterization
in the context of particle mixing. We treat in detail the physically relevant
cases of two- and three-flavor neutrino oscillations, including the effective
measure of CP violation. We discuss experimental schemes for the transfer of
the quantum information encoded in single-neutrino states to spatially
delocalized two-flavor charged lepton states, thus showing, at least in
principle, that single-particle entangled states of neutrino mixing are
legitimate physical resources for quantum information tasks.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:04:04 GMT"
},
{
"version": "v2",
"created": "Wed, 21 Nov 2007 18:29:21 GMT"
},
{
"version": "v3",
"created": "Tue, 1 Jul 2008 20:31:02 GMT"
},
{
"version": "v4",
"created": "Sat, 5 Jul 2008 09:32:56 GMT"
},
{
"version": "v5",
"created": "Fri, 17 Apr 2009 05:27:16 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Blasone",
"Massimo",
""
],
[
"Dell'Anno",
"Fabio",
""
],
[
"De Siena",
"Silvio",
""
],
[
"Illuminati",
"Fabrizio",
""
]
] |
0707.4477 | Amanda Kepley | Amanda A. Kepley, Heather L. Morrison, Amina Helmi, T.D. Kinman,
Jeffrey Van Duyne, John C. Martin, Paul Harding, John E. Norris, and Kenneth
C. Freeman | Halo Star Streams in the Solar Neighborhood | 46 pages, 13 figures, and 9 tables. Minor changes to text to match
proofed version of the paper. Low resolution figures. High resolution version
at http://www.astro.wisc.edu/~kepley/solar_streams.ps | Astron.J.134:1579-1595,2007 | 10.1086/521429 | null | astro-ph | null | We have assembled a sample of halo stars in the solar neighborhood to look
for halo substructure in velocity and angular momentum space. Our sample
includes red giants, RR Lyrae, and red horizontal branch stars within 2.5 kpc
of the Sun with [Fe/H] less than -1.0. It was chosen to include stars with
accurate distances, space velocities, and metallicities as well as
well-quantified errors. We confirm the existence of the streams found by Helmi
and coworkers, which we refer to as the H99 streams. These streams have a
double-peaked velocity distribution in the z direction. We use the results of
modeling of the H99 streams by Helmi and collaborators to test how one might
use v_z velocity information and radial velocity information to detect
kinematic substructure in the halo. We find that detecting the H99 streams with
radial velocities alone would require a large sample. We use the velocity
distribution of the H99 streams to estimate their age. From our model of the
progenitor of the H99 streams, we determine that it was accreted between 6 and
9 Gyr ago. The H99 streams have [alpha/Fe] abundances similar to other halo
stars in the solar neighborhood, suggesting that the gas that formed these
stars were enriched mostly by Type II SNe. We have also discovered in angular
momentum space two other possible substructures, which we refer to as the
retrograde and prograde outliers. The retrograde outliers are likely to be halo
substructure, but the prograde outliers are most likely part of the smooth
halo. The retrograde outliers have significant structure in the v_phi direction
and show a range of [alpha/Fe]. The methods presented in this paper can be used
to exploit the kinematic information present in future large databases like
RAVE, SDSSII/SEGUE, and Gaia.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:16:11 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 16:52:43 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Kepley",
"Amanda A.",
""
],
[
"Morrison",
"Heather L.",
""
],
[
"Helmi",
"Amina",
""
],
[
"Kinman",
"T. D.",
""
],
[
"Van Duyne",
"Jeffrey",
""
],
[
"Martin",
"John C.",
""
],
[
"Harding",
"Paul",
""
],
[
"Norris",
"John E.",
""
],
[
"Freeman",
"Kenneth C.",
""
]
] |
0707.4478 | Daniel Kocevski | Daniel Kocevski, Nathaniel Butler | GRB Energetics in the Swift Era | 30 pages, 10 figures, Accepted to ApJ | null | 10.1086/586693 | null | astro-ph | null | We examine the rest frame energetics of 76 gamma-ray bursts (GRBs) with known
redshift that were detected by the Swift spacecraft and monitored by the
satellite's X-ray Telescope (XRT). Using the bolometric fluence values
estimated in Butler et al. 2007b and the last XRT observation for each event,
we set a lower limit the their collimation corrected energy Eg and find that a
68% of our sample are at high enough redshift and/or low enough fluence to
accommodate a jet break occurring beyond the last XRT observation and still be
consistent with the pre-Swift Eg distribution for long GRBs. We find that
relatively few of the X-ray light curves for the remaining events show evidence
for late-time decay slopes that are consistent with that expected from post jet
break emission. The breaks in the X-ray light curves that do exist tend to be
shallower and occur earlier than the breaks previously observed in optical
light curves, yielding a Eg distribution that is far lower than the pre-Swift
distribution. If these early X-ray breaks are not due to jet effects, then a
small but significant fraction of our sample have lower limits to their
collimation corrected energy that place them well above the pre-Swift Eg
distribution. Either scenario would necessitate a much wider post-Swift Eg
distribution for long cosmological GRBs compared to the narrow standard energy
deduced from pre-Swift observations. We note that almost all of the pre-Swift
Eg estimates come from jet breaks detected in the optical whereas our sample is
limited entirely to X-ray wavelengths, furthering the suggestion that the
assumed achromaticity of jet breaks may not extend to high energies.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:11:52 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 00:00:55 GMT"
},
{
"version": "v3",
"created": "Wed, 2 Apr 2008 22:15:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kocevski",
"Daniel",
""
],
[
"Butler",
"Nathaniel",
""
]
] |
0707.4479 | Pasquier Noterdaeme | P. Noterdaeme, C. Ledoux, P. Petitjean, F. Le Petit, R. Srianand and
A. Smette | Excitation mechanisms in newly discovered H2-bearing Damped Lyman-alpha
clouds: systems with low molecular fractions | 16 pages, 25 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20078021 | null | astro-ph | null | We probe the physical conditions in high-redshift damped Ly-alpha systems
using the observed molecular fraction and the rotational excitation of
molecular hydrogen. We report two new detections of H2 at z = 2.402 and 1.989
toward, respectively, HE 0027-1836 and HE 2318-1107. We also present a detailed
analysis of our recent H2 detection toward Q2343+125. All three systems have
low molecular fractions, log f < -4, with f = 2N(H2)/(2N(H2) + N(HI)). Only one
such H2 system was known previously. The depletion patterns for Si, S, Ti, Cr,
Mn, Fe and Ni in the three systems are found to be very similar to what is
observed in diffuse gas of the Galactic halo. H2 absorption from rotational
levels up to J = 5 is observed in a single component toward HE 0027-1836. We
show that the width (Doppler parameter) of the H2 lines increases with
increasing J and that the kinetic energy derived from the Doppler parameter is
linearly dependent on the relative energy of the rotational levels. The
excitation temperature is found to be 90 K for J = 0 to J = 2 and ~500 K for
higher J levels. Single isothermal PDR models fail to reproduce the observed
rotational excitations. A two-component model is needed: one component of low
density (~50 cm-3) with weak illumination (chi = 1) to explain the J <= 2
rotational levels and another of high density (~500 cm-3) with strong
illumination (chi = 30) for J >= 3 levels. However, the juxtaposition of these
two PDR components may be ad-hoc and the multicomponent structure could result
either from turbulent dissipation or C-shocks.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:25:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Noterdaeme",
"P.",
""
],
[
"Ledoux",
"C.",
""
],
[
"Petitjean",
"P.",
""
],
[
"Petit",
"F. Le",
""
],
[
"Srianand",
"R.",
""
],
[
"Smette",
"A.",
""
]
] |
0707.4480 | Nilton Penha Dr. | Nilton Penha and Bernhard Rothenstein | A simple superluminal but not physical motion | 8 pages, 6 figures, Submitted on July/30/2007 | null | null | null | physics.gen-ph | null | We discuss a superluminal unphysical motion which, we believe, has a high
pedagogical potential. It highlights the physics behind the concept of
simultaneity in special relativity and illustrates the non-physical character
of superluminal speeds offering a rewarding exercise in handling the Minkowski
space-time diagram.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:17:15 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Penha",
"Nilton",
""
],
[
"Rothenstein",
"Bernhard",
""
]
] |
0707.4481 | Joshua Younger | Joshua D. Younger, T. J. Cox, Anil C. Seth, Lars Hernquist
(Harvard/CfA) | Antitruncated Stellar Disks via Minor Mergers | 10 pages, 11 figures, accepted to ApJ | null | 10.1086/521976 | null | astro-ph | null | We use hydrodynamic simulations of minor mergers of galaxies to investigate
the nature of surface brightness excesses at large radii observed in some
spiral galaxies: antitruncated stellar disks. We find that this process can
produce the antitruncation via two competing effects: (1) merger-driven gas
inflows that concentrate mass in the center of the primary galaxy and contract
its inner density profile; and (2) angular momentum transferred outwards by the
interaction, causing the outer disk to expand. In our experiments, this
requires both a significant supply of gas in the primary disk, and that the
encounter be prograde with moderate orbital angular momentum. The stellar
surface mass density profiles of our remnants both qualitatively and
quantitatively resemble the broken exponentials observed in local face--on
spirals that display antitruncations. Moreover, the observed trend towards more
frequent antitruncation relative to classical truncation in earlier Hubble
types is consistent with a merger-driven scenario.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:22:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Younger",
"Joshua D.",
"",
"Harvard/CfA"
],
[
"Cox",
"T. J.",
"",
"Harvard/CfA"
],
[
"Seth",
"Anil C.",
"",
"Harvard/CfA"
],
[
"Hernquist",
"Lars",
"",
"Harvard/CfA"
]
] |
0707.4482 | Thomas Greve | T.R. Greve (1), D. Stern (2), R.J. Ivison (3), C. De Breuck (4), A.
Kov\'acs (5), F. Bertoldi (6) ((1) Caltech, (2) JPL, (3) UK ATC/IfA
Edinburgh, (4) ESO, (5) MPIfR, (6) AlfA Bonn) | Wide-field mid-infrared and millimetre imaging of the high-redshift
radio galaxy, 4C41.17 | 20 pages, 9 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12292.x | null | astro-ph | null | We present deep 350- and 1200-micron imaging of the region around 4C41.17 --
one of the most distant (z = 3.792) and luminous known radio galaxies --
obtained with the Submillimeter High Angular Resolution Camera (SHARC-II) and
the Max Planck Millimeter Bolometer Array (MAMBO). The radio galaxy is robustly
detected at 350- and 1200-micron, as are two nearby 850-micron-selected
galaxies; a third 850-micron source is detected at 350-micron and coincides
with a ~ 2-sigma feature in the 1200-micron map. Further away from the radio
galaxy an additional nine sources are detected at 1200-micron, bringing the
total number of detected (sub)millimeter selected galaxies (SMGs) in this field
to 14. Using radio images from the Very Large Array (VLA) and Spitzer
mid-infrared (mid-IR) data, we find statistically robust radio and/or 24-micron
counterparts to eight of the 14 SMGs in the field around 4C41.17. Follow-up
spectroscopy with Keck/LRIS has yielded redshifts for three of the eight
robustly identified SMGs, placing them in the redshift range 0.5 < z < 2.7,
i.e. well below that of 4C41.17. We infer photometric redshifts for a further
four sources using their 1.6-micron (rest-frame) stellar feature as probed by
the IRAC bands; only one of them is likely to be at the same redshift as
4C41.17. Thus at least four, and as many as seven, of the SMGs within the
4C41.17 field are physically unrelated to the radio galaxy. With the redshift
information at hand we are able to constrain the observed over-densities of
SMGs within radial bins stretching to R=50 and 100" (~ 0.4 and ~ 0.8Mpc at z ~
3.8) from the radio galaxy to ~ 5x and ~ 2x that of the field, dropping off to
the background value at R=150". [Abridged]
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:37:41 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Greve",
"T. R.",
""
],
[
"Stern",
"D.",
""
],
[
"Ivison",
"R. J.",
""
],
[
"De Breuck",
"C.",
""
],
[
"Kovács",
"A.",
""
],
[
"Bertoldi",
"F.",
""
]
] |
0707.4483 | E. Bauer | E. Bauer | Quantum interference terms in nonmesonic weak decay of
$\Lambda$-hypernuclei within a RPA formalism | 39 pages, 10 figures | Nucl.Phys.A796:11-40,2007 | 10.1016/j.nuclphysa.2007.09.003 | null | nucl-th | null | Single and double coincidence nucleon spectra in the $\Lambda$-hypernuclei
weak decay are evaluated and discussed using a microscopic formalism. Nuclear
matter is employed together with the local density approximation which allows
us to analyze the $^{12}_{\Lambda}C$ hypernucleus non-mesonic weak decay. Final
state interactions (FSI) are included via the first order (in the nuclear
residual interaction) terms to the RPA, where the strong residual interaction
is modelled by a Bonn potential. At this level of approximation, these FSI are
pure quantum interference terms between the primary decay $(\Lambda N \to NN)$
and $(\Lambda N \to NN \to NN)$, where the strong interaction is responsible
for the last piece in the second reaction. Also the Pauli exchange
contributions are explicitly evaluated. We show that the inclusion of Pauli
exchange terms is important. A comparison with data is made. We conclude that
the limitations in phase space in the RPA makes this approximation inadequate
to reproduce the nucleon spectra. This fact, does not allow us to draw a
definite conclusion about the importance of the interference terms.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:41:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bauer",
"E.",
""
]
] |
0707.4484 | Sune Toft | S. Toft, P. van Dokkum, M. Franx, I. Labbe, N.M. Forster Schreiber, S.
Wuyts, T. Webb, G. Rudnick, A. Zirm, M. Kriek, P. van der Werf, J.P.
Blakeslee, G. Illingworth, H.-W. Rix, C. Papovich, A. Moorwood | HST and Spitzer imaging of red and blue galaxies at z~2.5: A correlation
between size and star formation activity from compact quiescent galaxies to
extended star forming galaxies | Accepted for publication in ApJ | Astrophys.J.671:285-302,2007 | 10.1086/521810 | null | astro-ph | null | We present HST NICMOS+ACS and Spitzer IRAC+MIPS observations of 41 galaxies
at 2<z<3.5 in the FIRES MS1054 field with red and blue rest-frame optical
colors. About half of the galaxies are very compact (effective radii r_e < 1
kpc) at rest-frame optical wavelengths, the others are extended (1< r_e < 10
kpc). For reference, 1 kpc corresponds to 0.12 arcsec at z=2.5 in the adopted
cosmology. We separate actively star forming galaxies from quiescent galaxies
by modeling their rest-frame UV-NIR SEDs. The star forming galaxies span the
full range of sizes, while the quiescent galaxies all have r_e<2kpc. In the
redshift range where MIPS 24 micron imaging is a sensitive probe of re-radiated
dust emission (z<2.5), the 24 micron fluxes confirm that the light of the small
quiescent galaxies is dominated by old stars, rather than dust-enshrouded star
formation or AGN activity. The inferred surface mass densities and velocity
dispersions for the quiescent galaxies are very high compared to those in local
galaxies. The galaxies follow a Kormendy relation (between surface brightness
and size) with approximately the same slope as locally, but shifted to brighter
surface brightnesses, consistent with a mean stellar formation redshift of
z_f~5. This paper demonstrates a direct relation between star formation
activity and size at z~2.5, and the existence of a significant population of
massive, extremely dense, old stellar systems without readily identifiable
counterparts in the local universe.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 19:35:03 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Toft",
"S.",
""
],
[
"van Dokkum",
"P.",
""
],
[
"Franx",
"M.",
""
],
[
"Labbe",
"I.",
""
],
[
"Schreiber",
"N. M. Forster",
""
],
[
"Wuyts",
"S.",
""
],
[
"Webb",
"T.",
""
],
[
"Rudnick",
"G.",
""
],
[
"Zirm",
"A.",
""
],
[
"Kriek",
"M.",
""
],
[
"van der Werf",
"P.",
""
],
[
"Blakeslee",
"J. P.",
""
],
[
"Illingworth",
"G.",
""
],
[
"Rix",
"H. -W.",
""
],
[
"Papovich",
"C.",
""
],
[
"Moorwood",
"A.",
""
]
] |
0707.4485 | Kevin Ann | Kevin Ann, Gregg Jaeger | Entanglement sudden death in qubit-qutrit systems | 10 pages. To appear in Physics Letters A | null | 10.1016/j.physleta.2007.07.070 | null | quant-ph | null | We demonstrate the existence of entanglement sudden death (ESD), the complete
loss of entanglement in finite time, in qubit-qutrit systems. In particular,
ESD is shown to occur in such systems initially prepared in a one-parameter
class of entangled mixed states and then subjected to local dephasing noise.
Together with previous results, this proves the existence of ESD for some
states in all quantum systems for which rigorously defined mixed-state
entanglement measures have been identified. We conjecture that ESD exists in
all quantum systems prepared in appropriate bipartite states.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 21:07:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ann",
"Kevin",
""
],
[
"Jaeger",
"Gregg",
""
]
] |
0707.4486 | David M. Bradley | David M. Bradley | A signed analog of Euler's reduction formula for the double zeta
function | 8 pages AMSLaTeX | null | null | null | math.CA math.NT | null | The double zeta function is a function of two arguments defined by a double
Dirichlet series, and was first studied by Euler in response to a letter from
Goldbach in 1742. By calculating many examples, Euler inferred a closed form
evaluation of the double zeta function in terms of values of the Riemann zeta
function, in the case when the two arguments are positive integers with
opposite parity. Here, we consider a signed analog of Euler's evaluation:
namely a reduction formula for the signed double zeta function that reduces to
Euler's evaluation when the signs are specialized to 1. This formula was first
stated in a 1997 paper by Borwein, Bradley and Broadhurst and was subsequently
proved by Flajolet and Salvy using contour integration. The purpose here is to
give an elementary proof based on a partial fraction identity.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:55:52 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Bradley",
"David M.",
""
]
] |
0707.4487 | Shimshon Jacobi | Jean-Pierre Eckmann, Shimshon Jacobi, Shimon Marom, Elisha Moses,
Cyrille Zbinden | Leadership in 2D living neural networks | null | null | null | New J. Phys. 10 (2008) 015011 | q-bio.NC | null | Eytan and Marom recently showed that the spontaneous burst activity of rat
neuron cultures includes `first to fire' cells that consistently fire earlier
than others. Here we analyze the behavior of these neurons in long term
recordings of spontaneous activity of rat hippocampal and rat cortical neuron
cultures from three different laboratories. We identify precursor events that
may either subside (`small events') or can lead to a full-blown burst
(`pre-bursts'). We find that the activation in the pre-burst typically has a
first neuron (`leader'), followed by a localized response in its neighborhood.
Locality is diminished in the bursts themselves. The long term dynamics of the
leaders is relatively robust, evolving with a half-life of 23-34 hours.
Stimulation of the culture can temporarily alter the leader distribution, but
it returns to the previous distribution within about 1 hour. We show that the
leaders carry information about the identity of the burst, as measured by the
signature of the number of spikes per neuron in a burst. The number of spikes
from leaders in the first few spikes of a precursor event is furthermore shown
to be predictive with regard to the transition into a burst (pre-burst versus
small event). We conclude that the leaders play a r\^ole in the development of
the bursts, and conjecture that they are part of an underlying sub-network that
is excited first and then act as nucleation centers for the burst.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 21:14:47 GMT"
}
] | 2010-04-19T00:00:00 | [
[
"Eckmann",
"Jean-Pierre",
""
],
[
"Jacobi",
"Shimshon",
""
],
[
"Marom",
"Shimon",
""
],
[
"Moses",
"Elisha",
""
],
[
"Zbinden",
"Cyrille",
""
]
] |
0707.4488 | Khoa Tran | Khoa Tran | Expected Utility Optimization - Calculus of Variations Approach | null | null | null | null | math.OC math.NA | null | In this paper, I'll derive the Hamilton-Jacobi (HJ) equation for Merton's
problem in Utility Optimization Theory using a Calculus of Variations (CoV)
Approach. For stochastic control problems, Dynamic Programming (DP) has been
used as a standard method. To the best of my knowledge, no one has used CoV for
this problem. In addition, while the DP approach cannot guarantee that the
optimum satisfies the HJ equation, the CoV approach does.
Be aware that this is the first draft of this paper and many flaws might be
introduced.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 20:59:26 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Tran",
"Khoa",
""
]
] |
0707.4489 | Turlough Neary | Turlough Neary and Damien Woods | Small weakly universal Turing machines | null | null | null | null | cs.CC | null | We give small universal Turing machines with state-symbol pairs of (6, 2),
(3, 3) and (2, 4). These machines are weakly universal, which means that they
have an infinitely repeated word to the left of their input and another to the
right. They simulate Rule 110 and are currently the smallest known weakly
universal Turing machines.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 21:40:55 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Neary",
"Turlough",
""
],
[
"Woods",
"Damien",
""
]
] |
0707.4490 | Peter Stone | Peter R. Stone, Jeffrey W. Beeman, Kin M. Yu, and Oscar D. Dubon | Tuning of ferromagnetism through anion substitution in Ga-Mn-pnictide
ferromagnetic semiconductors | 14 pages, 4 figures. Accepted for publication in the Proceedings of
the 24th International Conference on Defects in Semiconductors, which will be
released in the journal Physica B: Condensed Matter | Physica B 401-402, 454 (2007) | 10.1016/j.physb.2007.08.210 | null | cond-mat.mtrl-sci | null | We have synthesized Ga1-xMnxAs1-yPy and Ga1-xMnxP1-yNy by the combination of
ion implantation and pulsed-laser melting. We find that the incorporation of
isovalent impurities with smaller atomic radii leads to a realignment of the
magnetic easy axis in Ga1-xMnxP1-yNy/GaP and Ga1-xMnxAs1-yPy/GaAs thin films
from in-plane to out-of-plane. This tensile-strain-induced magnetic anisotropy
is reminiscent of that observed in Ga1-xMnxAs grown on larger lattice constant
(In,Ga)As buffer layers indicating that the role of strain in determining
magnetic anisotropy is fundamental to III-Mn-V materials. In addition, we
observe a decrease in the ferromagnetic Curie temperature in Ga1-xMnxAs1-yPy
with increasing y from 0 to 0.028. Such a decrease may result from localization
of holes as the P/As ratio on the Group V sublattice increases.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 21:07:21 GMT"
}
] | 2008-11-13T00:00:00 | [
[
"Stone",
"Peter R.",
""
],
[
"Beeman",
"Jeffrey W.",
""
],
[
"Yu",
"Kin M.",
""
],
[
"Dubon",
"Oscar D.",
""
]
] |
0707.4491 | Milton David Jara | Milton D. Jara | Non-equilibrium scaling limit for a tagged particle in the simple
exclusion process with long jumps | 14 pages | Communication on Pure and Applied Mathematics 62 (2009), no. 2,
198--214 | 10.1002/cpa.20253 | null | math.PR math-ph math.MP | null | We prove an invariance principle for a tagged particle in a simple exclusion
process out of equilibrium. The scaling limit is a time-inhomogeneous process
of independent increments, related to the solution of a fractional heat
equation.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:06:09 GMT"
}
] | 2009-04-24T00:00:00 | [
[
"Jara",
"Milton D.",
""
]
] |
0707.4492 | Ramesh Narayan | Jeffrey E. McClintock, Ramesh Narayan, Rebecca Shafee | Estimating the Spins of Stellar-Mass Black Holes | 10 Pages, 3 Figures, 1 Table. To appear in Black Holes, eds. M. Livio
and A. Koekemoer (Cambridge University Press), in press (2008) | null | null | null | astro-ph | null | We describe a program that we have embarked on to estimate the spins of
stellar-mass black holes in X-ray binaries. We fit the continuum X-ray spectrum
of the radiation from the accretion disk using the standard thin disk model,
and extract the dimensionless spin parameter a* = a/M of the black hole as a
parameter of the fit. We have obtained results on three systems, 4U 1543-47 (a*
= 0.7-0.85), GRO J1655-40 (0.65-0.8), and GRS 1915+105 (0.98-1), and have
nearly completed analysis of two additional systems. We anticipate expanding
the sample of spin estimates to about a dozen over the next several years.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:14:16 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"McClintock",
"Jeffrey E.",
""
],
[
"Narayan",
"Ramesh",
""
],
[
"Shafee",
"Rebecca",
""
]
] |
0707.4493 | Richard Harley | P. S. Eldridge, W. J. H. Leyland, P. G. Lagoudakis, O. Z. Karimov, M.
Henini, D. Taylor, R. T. Phillips and R. T. Harley | Temperature Dependence of Rashba Spin-orbit Coupling in Quantum Wells | null | null | null | null | cond-mat.other | null | We perform an all-optical spin-dynamic measurement of the Rashba spin-orbit
interaction in (110)-oriented GaAs/AlGaAs quantum wells. The crystallographic
direction of quantum confinement allows us to disentangle the contributions to
spin-orbit coupling from the structural inversion asymmetry (Rashba term) and
the bulk inversion asymmetry. We observe an unexpected temperature dependence
of the Rashba spin-orbit interaction strength that signifies the importance of
the usually neglected higher-order terms of the Rashba coupling.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:17:31 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Eldridge",
"P. S.",
""
],
[
"Leyland",
"W. J. H.",
""
],
[
"Lagoudakis",
"P. G.",
""
],
[
"Karimov",
"O. Z.",
""
],
[
"Henini",
"M.",
""
],
[
"Taylor",
"D.",
""
],
[
"Phillips",
"R. T.",
""
],
[
"Harley",
"R. T.",
""
]
] |
0707.4494 | Paolo Ghiggini | Paolo Ghiggini | On tight contact structures with negative maximal twisting number on
small Seifert manifolds | 16 pages, 4 figures, exposition improved | null | null | null | math.GT | null | We study some properties of transverse contact structures on small Seifert
manifolds, and we apply them to the classification of tight contact structures
on a family of small Seifert manifolds.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:21:16 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 04:43:10 GMT"
}
] | 2007-10-10T00:00:00 | [
[
"Ghiggini",
"Paolo",
""
]
] |
0707.4495 | Tucci Kay Dr. | C. Echeverria, K. Tucci, M. G. Cosenza | Phase growth in bistable systems with impurities | 7 pages, 12 figures | null | 10.1103/PhysRevE.77.016204 | null | nlin.PS cond-mat.dis-nn nlin.CD | null | A system of coupled chaotic bistable maps on a lattice with randomly
distributed impurities is investigated as a model for studying the phenomenon
of phase growth in nonuniform media. The statistical properties of the system
are characterized by means of the average size of spatial domains of equivalent
spin variables that define the phases. It is found that the rate at which phase
domains grow becomes smaller when impurities are present and that the average
size of the resulting domains in the inhomogeneous state of the system
decreases when the density of impurities is increased. The phase diagram
showing regions where homogeneous, heterogeneous, and chessboard patterns occur
on the space of parameters of the system is obtained. A critical boundary that
separates the regime of slow growth of domains from the regime of fast growth
in the heterogeneous region of the phase diagram is calculated. The transition
between these two growth regimes is explained in terms of the stability
properties of the local phase configurations. Our results show that the
inclusion of spatial inhomogeneities can be used as a control mechanism for the
size and growth velocity of phase domains forming in spatiotemporal systems.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:30:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Echeverria",
"C.",
""
],
[
"Tucci",
"K.",
""
],
[
"Cosenza",
"M. G.",
""
]
] |
0707.4496 | Jonathan Kirby | Jonathan Kirby | On Quasiminimal Excellent Classes | 16 pages. v3: correction to the statement of corollary 5.7 | J. Symbolic Logic 75 (2010), no. 2, 551-564 | 10.2178/jsl/1268917494 | null | math.LO | null | A careful exposition of Zilber's quasiminimal excellent classes and their
categoricity is given, leading to two new results: the L_w1,w(Q)-definability
assumption may be dropped, and each class is determined by its model of
dimension aleph_0.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:39:25 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 16:20:38 GMT"
},
{
"version": "v3",
"created": "Mon, 17 Dec 2007 14:00:03 GMT"
}
] | 2011-08-05T00:00:00 | [
[
"Kirby",
"Jonathan",
""
]
] |
0707.4497 | Patrick De Leenheer | Patrick De Leenheer and Sergei S. Pilyugin | Immune response to a malaria infection: properties of a mathematical
model | null | null | null | null | q-bio.CB | null | We establish some properties of a within host mathematical model of malaria
proposed by Recker et al which includes the role of the immune system during
the infection. The model accounts for the antigenic variation exhibited by the
malaria parasite (P. falciparum). We show that the model can exhibit a wide
variety of dynamical behaviors. We provide criteria for global stability,
competitive exclusion, and persistence. We also demonstrate that the disease
equilibrium can be destabilized by non-symmetric cross-reactive responses.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:49:01 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"De Leenheer",
"Patrick",
""
],
[
"Pilyugin",
"Sergei S.",
""
]
] |
0707.4498 | Joshua Beun | J. Beun, G. C. McLaughlin, R. Surman, W. R. Hix | Fission Cycling in a Supernova r-process | 9 pages, 8 figures | Phys.Rev.C77:035804,2008 | 10.1103/PhysRevC.77.035804 | null | astro-ph | null | Recent halo star abundance observations exhibit an important feature of
consequence to the r-process: the presence of a main r-process between the
second and third peaks which is consistent among halo stars. We explore fission
cycling and steady-beta flow as the driving mechanisms behind this feature. The
presence of fission cycling during the r-process can account for
nucleosynthesis yields between the second and third peaks, whereas the presence
of steady-beta flow can account for consistent r-process patterns, robust under
small variations in astrophysical conditions. We employ the neutrino-driven
wind of the core-collapse supernova to examine fission cycling and steady-beta
flow in the r-process. As the traditional neutrino-driven wind model does not
produce the required very neutron-rich conditions for these mechanisms, we
examine changes to the neutrino physics necessary for fission cycling to occur
in the neutrino-driven wind environment, and we explore under what conditions
steady-beta flow is obtained.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:57:10 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Beun",
"J.",
""
],
[
"McLaughlin",
"G. C.",
""
],
[
"Surman",
"R.",
""
],
[
"Hix",
"W. R.",
""
]
] |
0707.4499 | Vladimir Nikiforov | Vladimir Nikiforov | A spectral condition for odd cycles in graphs | The main theorem is improved. Updated references | null | null | null | math.CO | null | We give a sharp spectral condition for the existence of odd cycles in a graph
of given order. We also prove a related stability result.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 22:50:37 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 00:15:59 GMT"
}
] | 2007-11-22T00:00:00 | [
[
"Nikiforov",
"Vladimir",
""
]
] |
0707.4500 | Simone Migliari | S. Migliari (CASS/UCSD), J.A. Tomsick (SSL/UCB), S. Markoff
(Amsterdam), E. Kalemci (Sabanci U.), C.D. Bailyn (Yale), M. Buxton (Columbia
U.), S. Corbel (Paris VII/CEA-Saclay), R.P. Fender (Southampton), P. Kaaret
(U. Iowa) | Tracing the jet contribution to the mid-IR over the 2005 outburst of GRO
J1655-40 via broadband spectral modeling | accepted for publication in ApJ | null | 10.1086/522023 | null | astro-ph | null | We present new results from a multi-wavelength (radio/infrared/optical/X-ray)
study of the black hole X-ray binary GRO J1655-40 during its 2005 outburst. We
detected, for the first time, mid-infrared emission at 24 um from the compact
jet of a black hole X-ray binary during its hard state, when the source shows
emission from a radio compact jet as well as a strong non-thermal hard X-ray
component. These detections strongly constrain the optically thick part of the
synchrotron spectrum of the compact jet, which is consistent with being flat
over four orders of magnitude in frequency. Moreover, using this unprecedented
coverage, and especially thanks to the new Spitzer observations, we can test
broadband disk and jet models during the hard state. Two of the hard state
broadband spectra are reasonably well fitted using a jet model with parameters
overall similar to those previously found for Cyg X-1 and GX 339-4. Differences
are also present; most notably, the jet power in GRO J1655-40 appears to be a
factor of at least ~3-5 higher (depending on the distance) than that of Cyg X-1
and GX 339-4 at comparable disk luminosities. Furthermore, a few discrepancies
between the model and the data, previously not found for the other two black
hole systems for which there was no mid-IR/IR and optical coverage, are
evident, and will help to constrain and refine theoretical models.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 23:00:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Migliari",
"S.",
"",
"CASS/UCSD"
],
[
"Tomsick",
"J. A.",
"",
"SSL/UCB"
],
[
"Markoff",
"S.",
"",
"Amsterdam"
],
[
"Kalemci",
"E.",
"",
"Sabanci U."
],
[
"Bailyn",
"C. D.",
"",
"Yale"
],
[
"Buxton",
"M.",
"",
"Columbia\n U."
],
[
"Corbel",
"S.",
"",
"Paris VII/CEA-Saclay"
],
[
"Fender",
"R. P.",
"",
"Southampton"
],
[
"Kaaret",
"P.",
"",
"U. Iowa"
]
] |
0707.4501 | Patrick De Leenheer | Patrick De Leenheer and Sergei S. Pilyugin | Multi-strain virus dynamics with mutations: A global analysis | null | null | null | null | q-bio.CB | null | We consider within-host virus models with more than one strain and allow
mutation between the strains. If there is no mutation, a Lyapunov function
establishes global stability of the steady state corresponding to the fittest
strain. For small perturbations this steady state persists, perhaps with small
concentrations of some or all other strains, depending on the connectivity of
the graph describing all possible mutations. Moreover, using a perturbation
result due to Smith and Waltman, we show that this steady state also preserves
global stability.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 23:03:52 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"De Leenheer",
"Patrick",
""
],
[
"Pilyugin",
"Sergei S.",
""
]
] |
0707.4502 | Abramo Hefez | Abramo Hefez and Marcelo E. Hernandes | The Analytic Classification of Plane Branches | 19 pages, two tables | null | 10.1112/blms/bdq113 | null | math.AG | null | In this paper we give a solution to Zariski's problem of analytic
classification of plane branches.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 23:13:01 GMT"
}
] | 2014-02-26T00:00:00 | [
[
"Hefez",
"Abramo",
""
],
[
"Hernandes",
"Marcelo E.",
""
]
] |
0707.4503 | Kim Montgomery | K. A. Montgomery | Multifrequency Forcing of a Hopf Oscillator Model of the Inner Ear | 19 pages, 2 figures | null | 10.1529/biophysj.107.118604 | null | nlin.PS | null | In response to a sound stimulus, the inner ear emits sounds called
otoacoustic emissions. While the exact mechanism for the production of
otoacoustic emissions is not known, active motion of individual hair cells is
thought to play a role. Two possible sources for otoacoustic emissions, both
localized within individual hair cells, include somatic motility and hair
bundle motility. Because physiological models of each of these systems are
thought to be poised near a Hopf bifurcation, the dynamics of each can be
described by the normal form for a system near a Hopf bifurcation. Here we
demonstrate that experimental results from three-frequency suppression
experiments can be predicted based on the response of an array of
noninteracting Hopf oscillators tuned at different frequencies. This supports
the idea that active motion of individual hair cells contributes to active
processing of sounds in the ear. Interestingly, the model suggests an
explanation for differing results recorded in mammals and nonmammals.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 23:44:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Montgomery",
"K. A.",
""
]
] |
0707.4504 | Kate Sugden Ms | K. E. P. Sugden, M. R. Evans | A dynamically extending exclusion process | 20 pages, 12 figures | J. Stat. Mech. (2007) P11013 | 10.1088/1742-5468/2007/11/P11013 | null | cond-mat.stat-mech | null | An extension of the totally asymmetric exclusion process, which incorporates
a dynamically extending lattice is explored. Although originally inspired as a
model for filamentous fungal growth, here the dynamically extending exclusion
process (DEEP) is studied in its own right, as a nontrivial addition to the
class of nonequilibrium exclusion process models. Here we discuss various
mean-field approximation schemes and elucidate the steady state behaviour of
the model and its associated phase diagram. Of particular note is that the
dynamics of the extending lattice leads to a new region in the phase diagram in
which a shock discontinuity in the density travels forward with a velocity that
is lower than the velocity of the tip of the lattice. Thus in this region the
shock recedes from both boundaries.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 09:09:57 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 18:03:11 GMT"
},
{
"version": "v3",
"created": "Mon, 29 Oct 2007 11:47:14 GMT"
}
] | 2007-12-10T00:00:00 | [
[
"Sugden",
"K. E. P.",
""
],
[
"Evans",
"M. R.",
""
]
] |
0707.4505 | Minh Huynh | Minh T. Huynh, David T. Frayer, Bahram Mobasher, Mark Dickinson,
Ranga-Ram Chary, Glenn Morrison | The Far-Infrared Luminosity Function from GOODS-N: Constraining the
Evolution of Infrared Galaxies for z \leq 1 | accepted by ApJL, 5 pages | Astrophys.J.667:L9-L12,2007 | 10.1086/521981 | null | astro-ph | null | We present the IR luminosity function derived from ultra-deep 70 micron
imaging of the GOODS-North field. The 70 micron observations are longward of
the PAH and silicate features which complicate work in the MIR. We derive
far-infrared luminosities for the 143 sources with S_{70} > 2 mJy (S/N > 3
\sigma). The majority (81%) of the sources have spectroscopic redshifts, and
photometric redshifts are calculated for the remainder. The IR luminosity
function at four redshifts (z ~ 0.28, 0.48, 0.78, and 0.97) is derived and
compared to the local one. There is considerable degeneracy between luminosity
and density evolution. If the evolving luminosity function is described as
\rho(L, z) = (1 + z)^q \rho(L/(1 + z)^p, 0), we find q = -2.19p + 6.09. In the
case of pure luminosity evolution, we find a best fit of p =
2.78^{+0.34}_{-0.32}. This is consistent with the results from 24 micron and
1.4 GHz studies. Our results confirm the emerging picture of strong evolution
in LIRGs and ULIRGs at 0.4 < z < 1.1, but we find no evidence of significant
evolution in the sub-LIRG (L < 10^{11} L_{\odot}) population for z < 0.4.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 23:41:22 GMT"
}
] | 2012-08-30T00:00:00 | [
[
"Huynh",
"Minh T.",
""
],
[
"Frayer",
"David T.",
""
],
[
"Mobasher",
"Bahram",
""
],
[
"Dickinson",
"Mark",
""
],
[
"Chary",
"Ranga-Ram",
""
],
[
"Morrison",
"Glenn",
""
]
] |
0707.4506 | Bo Thid\'e | Bo Thid\'e | Nonlinear physics of the ionosphere and LOIS/LOFAR | Six pages, two figures. To appear in Plasma Physics and Controlled
Fusion | Plasma Phys. Control. Fusion, 49(12B):B103-B107, 14 November 2007 | 10.1088/0741-3335/49/12B/S09 | null | physics.plasm-ph | null | The ionosphere is the only large-scale plasma laboratory without walls that
we have direct access to. From results obtained in systematic, repeatable
experiments in this natural laboratory, where we can vary the stimulus and
observe its response in a controlled, repeatable manner, we can draw
conclusions on similar physical processes occurring naturally in the Earth's
plasma environment as well as in parts of the plasma universe that are not
easily accessible to direct probing.
Of particular interest is electromagnetic turbulence excited in the
ionosphere by beams of particles (photons, electrons) and its manifestation in
terms of secondary radiation (electrostatic and electromagnetic waves),
structure formation (solitons, cavitons, alfveons, striations), and the
associated exchange of energy, linear momentum, and angular momentum.
We present a new diagnostic technique, based on vector radio allowing the
utilization of EM angular momentum (vorticity), to study plasma turbulence
remotely.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 01:36:58 GMT"
}
] | 2009-05-02T00:00:00 | [
[
"Thidé",
"Bo",
""
]
] |
0707.4507 | Neri Merhav | Yaniv Akirav and Neri Merhav | Competitive minimax universal decoding for several ensembles of random
codes | 41 pages; submitted to IEEE Transactions on Information Theory | null | null | null | cs.IT math.IT | null | Universally achievable error exponents pertaining to certain families of
channels (most notably, discrete memoryless channels (DMC's)), and various
ensembles of random codes, are studied by combining the competitive minimax
approach, proposed by Feder and Merhav, with Chernoff bound and Gallager's
techniques for the analysis of error exponents. In particular, we derive a
single--letter expression for the largest, universally achievable fraction
$\xi$ of the optimum error exponent pertaining to the optimum ML decoding.
Moreover, a simpler single--letter expression for a lower bound to $\xi$ is
presented. To demonstrate the tightness of this lower bound, we use it to show
that $\xi=1$, for the binary symmetric channel (BSC), when the random coding
distribution is uniform over: (i) all codes (of a given rate), and (ii) all
linear codes, in agreement with well--known results. We also show that $\xi=1$
for the uniform ensemble of systematic linear codes, and for that of
time--varying convolutional codes in the bit-error--rate sense. For the latter
case, we also show how the corresponding universal decoder can be efficiently
implemented using a slightly modified version of the Viterbi algorithm which em
employs two trellises.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 23:57:35 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Akirav",
"Yaniv",
""
],
[
"Merhav",
"Neri",
""
]
] |
0707.4508 | Leonardo Ermann | Leonardo Ermann, Gabriel G. Carlo and Marcos Saraceno | Transport phenomena in the asymmetric quantum multibaker map | 5 pages, 3 figures. Accepted version, minor changes, Journal-ref
added | Phys. Rev. E 77, 011126 (2008) | 10.1103/PhysRevE.77.011126 | null | quant-ph nlin.CD | null | By studying a modified (unbiased) quantum multibaker map, we were able to
obtain a {\em finite} asymptotic quantum current without a classical analogue.
This result suggests a general method for the design of {\em purely} quantum
ratchets, and sheds light on the investigation of the mechanisms leading to net
transport generation by breaking symmetries of quantum systems. Moreover, we
propose the multibaker map as a resource to study directed transport phenomena
in chaotic systems without bias. In fact, this is a paradigmatic model in
classical and quantum chaos, but also in statistical mechanics.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 00:00:04 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 21:03:53 GMT"
},
{
"version": "v3",
"created": "Thu, 31 Jan 2008 17:01:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ermann",
"Leonardo",
""
],
[
"Carlo",
"Gabriel G.",
""
],
[
"Saraceno",
"Marcos",
""
]
] |
0707.4509 | Nairn Baliber | L. Cieza and N. Baliber | Testing the Disk Regulation Paradigm with Spitzer Observations. II. A
Clear Signature of Star-Disk Interaction in NGC 2264 and the Orion Nebula
Cluster | 31 pages, 7 figures, 2 tables. Accepted for publication in ApJ | Astrophys.J.671:605-615,2007 | 10.1086/522080 | null | astro-ph | null | Observations of PMS star rotation periods reveal slow rotators in young
clusters of various ages, indicating that angular momentum is somehow removed
from these rotating masses. The mechanism by which spin-up is regulated as
young stars contract has been one of the longest-standing problems in star
formation. Attempts to observationally confirm the prevailing theory that
magnetic interaction between the star and its circumstellar disk regulates
these rotation periods have produced mixed results. In this paper, we use the
unprecedented disk identification capability of the Spitzer Space Telescope to
test the star-disk interaction paradigm in two young clusters, NGC 2264 and the
Orion Nebula Cluster (ONC). We show that once mass effects and sensitivity
biases are removed, a clear increase in the disk fraction with period can be
observed in both clusters across the entire period range populated by cluster
members. We also show that the long-period peak (P $\sim$8 days) of the bimodal
distribution observed for high-mass stars in the ONC is dominated by a
population of stars possessing a disk, while the short-period peak (P $\sim$2
days) is dominated by a population of stars without a disk. Our results
represent the strongest evidence to date that star-disk interaction regulates
the angular momentum of these young stars. This study will make possible
quantitative comparisons between the observed period distributions of stars
with and without a disk and numerical models of the angular momentum evolution
of young stars.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 00:01:34 GMT"
}
] | 2009-12-08T00:00:00 | [
[
"Cieza",
"L.",
""
],
[
"Baliber",
"N.",
""
]
] |
0707.4510 | Sugumi Kanno | Sugumi Kanno, David Langlois, Misao Sasaki, Jiro Soda | Kaluza-Klein braneworld cosmology with static internal dimensions | 9 pages. References added | Prog.Theor.Phys.118:701-713,2007 | 10.1143/PTP.118.701 | null | hep-th astro-ph gr-qc | null | We investigate the Kaluza-Klein braneworld cosmology from the point of view
of observers on the brane. We first generalize the Shiromizu-Maeda-Sasaki (SMS)
equations to higher dimensions. As an application, we study a (4+n)-dimensional
brane with n dimensions compactified on the brane, in a (5+n)-dimensional bulk.
By assuming that the size of the internal space is static, that the bulk
energy-momentum tensor can be neglected, we determine the effect of the bulk
geometry on the Kaluza-Klein braneworld. Then we derive the effective Friedmann
equation on the brane. It turns out that the Friedmann equation explicitly
depends on the equation of state, in contrast to the braneworld in a
5-dimensional bulk spacetime. In particular, in a radiation-dominated era, the
effective Newton constant depends on the scale factor logarithmically. If we
include a pressureless matter on the brane, this dependence disappears after
the radiation-matter equality. This may be interpreted as stabilization of the
Newton constant by the matter on the brane. Our findings imply that the
Kaluza-Klein braneworld cosmology is quite different from the conventional
Kaluza-Klein cosmology even at low energy.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 00:03:32 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 03:33:03 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kanno",
"Sugumi",
""
],
[
"Langlois",
"David",
""
],
[
"Sasaki",
"Misao",
""
],
[
"Soda",
"Jiro",
""
]
] |
0707.4511 | Stephan Narison | G. Mennessier, P. Minkowski, S. Narison and W. Ochs | Can the gamma-gamma processes reveal the nature of the sigma ? | null | null | null | null | hep-ph | null | We reanalyse the gamma-gamma scattering data and conclude that in the mass
region below 1 GeV the cross section for gamma-gamma to pi^0-pi^0 can be
largely explained by the one pion exchange process with pi-pi rescattering. The
radiative width of the sigma is estimated and a model dependent separation into
contributions from direct gamma-gamma decay and decay through rescattering is
obtained. We confront these findings with QCD spectral sum rule (QSSR)
predictions and conclude that the sigma can have a large gluonium component in
its wave function.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 19:59:40 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Aug 2007 09:08:33 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Mennessier",
"G.",
""
],
[
"Minkowski",
"P.",
""
],
[
"Narison",
"S.",
""
],
[
"Ochs",
"W.",
""
]
] |
0707.4512 | Martin Fuechsle | M. Fuechsle, J. Bentner, D. A. Ryndyk, M. Reinwald, W. Wegscheider,
and C. Strunk | Effect of Microwaves on the Current-Phase-Relation in SNS Josephson
Junctions | 5 pages; accepted for publication in Phys. Rev. Lett | null | null | null | cond-mat.mes-hall | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the current-phase-relation (CPR) of long diffusive
superconductor-normal metal-superconductor (SNS) Josephson junctions in
thermodynamic equilibrium and under microwave irradiation. While in equilibrium
good agreement with the predictions of quasi-classical theory is found, we
observe that the shape of the CPR can be strongly affected by microwave
irradiation. Close to a Josephson-phase difference of pi, the supercurrent can
be strongly suppressed when increasing the rf-power. Our results can be
understood in terms of microwave excitation of low-lying Andreev bound states
across the mini-gap in the junction. In the frequency interval studied, this
mechanism becomes important when the mini-gap closes at a phase difference of
pi.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 04:49:26 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Dec 2007 07:30:12 GMT"
},
{
"version": "v3",
"created": "Tue, 24 Feb 2009 08:51:02 GMT"
}
] | 2009-02-24T00:00:00 | [
[
"Fuechsle",
"M.",
""
],
[
"Bentner",
"J.",
""
],
[
"Ryndyk",
"D. A.",
""
],
[
"Reinwald",
"M.",
""
],
[
"Wegscheider",
"W.",
""
],
[
"Strunk",
"C.",
""
]
] |
0707.4513 | Simone Speziale | Bianca Dittrich, Laurent Freidel and Simone Speziale | Linearized dynamics from the 4-simplex Regge action | 16 (+9 Appendix) pages, 1 figure | Phys.Rev.D76:104020,2007 | 10.1103/PhysRevD.76.104020 | pi-qg-48 | gr-qc hep-lat | null | We study the relation between the hessian matrix of the riemannian Reggae
action on a 4-simplex and linearized quantum gravity. We give an explicit
formula for the hessian as a function of the geometry, and show that it has a
single zero mode. We then use a 3d lattice model to show that (i) the zero mode
is a remnant of the continuum diffeomorphism invariance, and (ii) we recover
the complete free graviton propagator in the continuum limit. The results help
clarify the structure of the boundary state needed in the recent calculations
of the graviton propagator in loop quantum gravity, and in particular its role
in fixing the gauge.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 00:28:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dittrich",
"Bianca",
""
],
[
"Freidel",
"Laurent",
""
],
[
"Speziale",
"Simone",
""
]
] |
0707.4514 | Jess Broderick | J. W. Broderick, J. J. Bryant, R. W. Hunstead, E. M. Sadler and T.
Murphy (University of Sydney) | A new search for distant radio galaxies in the southern hemisphere - I.
Sample definition and radio properties | 28 pages, 9 figures, 10 tables, accepted for publication in MNRAS.
Correct version of SUMSS catalogue now noted in Section 2.1.2; analysis and
conclusions unchanged. A higher-resolution version of Figure 1 is available
at http://www.physics.usyd.edu.au/~jess/papers.html | null | 10.1111/j.1365-2966.2007.12277.x | null | astro-ph | null | This paper introduces a new program to find high-redshift radio galaxies in
the southern hemisphere through ultra-steep spectrum (USS) selection. We define
a sample of 234 USS radio sources with spectral indices alpha_408^843 < -1.0
and flux densities S_408 > 200 mJy in a region of 0.35 sr, chosen by
cross-correlating the revised 408 MHz Molonglo Reference Catalogue, the 843 MHz
Sydney University Molonglo Sky Survey and the 1400 MHz NRAO VLA Sky Survey in
the overlap region -40 deg < delta < -30 deg. We present Australia Telescope
Compact Array (ATCA) high-resolution 1384 and 2368 MHz radio data for each
source, which we use to analyse the morphological, spectral index and
polarization properties of our sample. We find that 85 per cent of the sources
have observed-frame spectral energy distributions that are straight over the
frequency range 408-2368 MHz, and that, on average, sources with smaller
angular sizes have slightly steeper spectral indices and lower fractional
linear polarization. Fractional polarization is anti-correlated with flux
density at both 1400 and 2368 MHz. We also use the ATCA data to determine
observed-frame Faraday rotation measures for half of the sample.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 00:29:49 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 14:32:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Broderick",
"J. W.",
"",
"University of Sydney"
],
[
"Bryant",
"J. J.",
"",
"University of Sydney"
],
[
"Hunstead",
"R. W.",
"",
"University of Sydney"
],
[
"Sadler",
"E. M.",
"",
"University of Sydney"
],
[
"Murphy",
"T.",
"",
"University of Sydney"
]
] |
0707.4515 | Nathan Kaib | Nathan A. Kaib, Thomas Quinn | The Formation of the Oort Cloud in Open Cluster Environments | 65 pages, 14 figures, 3 tables, Accepted to Icarus | null | 10.1016/j.icarus.2008.03.020 | null | astro-ph | null | We study the influence of an open cluster environment on the formation and
current structure of the Oort cloud. To do this, we have run 19 different
simulations of the formation of the Oort Cloud for 4.5 Gyrs. In each
simulation, the solar system spends its first 100 Myrs in a different open
cluster environment before transitioning to its current field environment. We
find that, compared to forming in the field environment, the inner Oort Cloud
is preferentially loaded with comets while the Sun resides in the open cluster
and that most of this material remains locked in the interior of the cloud for
the next 4.4 Gyrs. In addition, the outer Oort Cloud trapping efficiencies we
observe in our simulations are lower than previous formation models by about a
factor of 2, possibly implying an even more massive early planetesimal disk.
Furthermore, some of our simulations reproduce the orbits of observed extended
scattered disk objects, which may serve as an observational constraint on the
Sun's early environment. Depending on the particular open cluster environment,
the properties of the inner Oort Cloud and extended scattered disk can vary
widely. On the other hand, the outer portions of the Oort Cloud in each of our
simulations are all similar.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 02:21:26 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 22:07:21 GMT"
},
{
"version": "v3",
"created": "Wed, 2 Apr 2008 04:16:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kaib",
"Nathan A.",
""
],
[
"Quinn",
"Thomas",
""
]
] |
0707.4516 | Young Jun Chang | Y. J. Chang, J. S. Yang, Y. S. Kim, D. H. Kim, T. W. Noh, D.-W. Kim,
E. OH, B. Kahng, J.-S. Chung | Surface versus bulk characterization of the electronic inhomogeneity in
a VO_{2} film | 27 pages and 7 figures | null | 10.1103/PhysRevB.76.075118 | null | cond-mat.str-el | null | We investigated the inhomogeneous electronic properties at the surface and
interior of VO_{2} thin films that exhibit a strong first-order metal-insulator
transition (MIT). Using the crystal structural change that accompanies a VO_{2}
MIT, we used bulk-sensitive X-ray diffraction (XRD) measurements to estimate
the fraction of metallic volume p^{XRD} in our VO_{2} film. The temperature
dependence of the p$^{XRD}$ was very closely correlated with the dc
conductivity near the MIT temperature, and fit the percolation theory
predictions quite well: $\sigma$ $\sim$ (p - p_{c})^{t} with t = 2.0$\pm$0.1
and p_{c} = 0.16$\pm$0.01. This agreement demonstrates that in our VO$_{2}$
thin film, the MIT should occur during the percolation process. We also used
surface-sensitive scanning tunneling spectroscopy (STS) to investigate the
microscopic evolution of the MIT near the surface. Similar to the XRD results,
STS maps revealed a systematic decrease in the metallic phase as temperature
decreased. However, this rate of change was much slower than the rate observed
with XRD, indicating that the electronic inhomogeneity near the surface differs
greatly from that inside the film. We investigated several possible origins of
this discrepancy, and postulated that the variety in the strain states near the
surface plays an important role in the broad MIT observed using STS. We also
explored the possible involvement of such strain effects in other correlated
electron oxide systems with strong electron-lattice interactions.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 00:54:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chang",
"Y. J.",
""
],
[
"Yang",
"J. S.",
""
],
[
"Kim",
"Y. S.",
""
],
[
"Kim",
"D. H.",
""
],
[
"Noh",
"T. W.",
""
],
[
"Kim",
"D. -W.",
""
],
[
"OH",
"E.",
""
],
[
"Kahng",
"B.",
""
],
[
"Chung",
"J. -S.",
""
]
] |
0707.4517 | Jacob Rubinstein | J. rubinstein, P. Sternberg and Q. Ma | Bifurcation diagram and pattern formation in superconducting wires with
electric currents | null | null | 10.1103/PhysRevLett.99.167003 | null | cond-mat.supr-con | null | We examine the behavior of a one-dimensional superconducting wire exposed to
an applied electric current. We use the time-dependent Ginzburg-Landau model to
describe the system and retain temperature and applied current as parameters.
Through a combination of spectral analysis, asymptotics and canonical numerical
computation, we divide this two-dimensional parameter space into a number of
regions. In some of them only the normal state or a stationary state or an
oscillatory state are stable, while in some of them two states are stable. One
of the most interesting features of the analysis is the evident collision of
real eigenvalues of the associated PT-symmetric linearization, leading as it
does to the emergence of complex elements of the spectrum. In particular this
provides an explanation to the emergence of a stable oscillatory state. We show
that part of the bifurcation diagram and many of the emerging patterns are
directly controlled by this spectrum, while other patterns arise due to
nonlinear interaction of the leading eigenfunctions.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 01:04:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"rubinstein",
"J.",
""
],
[
"Sternberg",
"P.",
""
],
[
"Ma",
"Q.",
""
]
] |
0707.4518 | Awlok Josan | Enrique J. Duarte-Melo, Awlok Josan, Mingyan Liu, David L. Neuhoff and
Sandeep Pradhan | On Throughput Scaling of Wireless Networks: Effect of Node Density and
Propagation Model | 28 pages, 4 figures | null | null | null | cs.IT math.IT | null | This paper derives a lower bound to the per-node throughput achievable by a
wireless network when n source-destination pairs are randomly distributed
throughout a disk of radius $n^\gamma$, $ \gamma \geq 0$, propagation is
modeled by attenuation of the form $1/(1+d)^\alpha$, $\alpha >2$, and
successful transmission occurs at a fixed rate W when received signal to noise
and interference ratio is greater than some threshold $\beta$, and at rate 0
otherwise. The lower bound has the form $n^{1-\gamma}$ when $\gamma < 1/2$, and
$(n \ln n)^{-1/2}$ when $\gamma \geq 1/2$. The methods are similar to, but
somewhat simpler than, those in the seminal paper by Gupta and Kumar.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 01:15:59 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Duarte-Melo",
"Enrique J.",
""
],
[
"Josan",
"Awlok",
""
],
[
"Liu",
"Mingyan",
""
],
[
"Neuhoff",
"David L.",
""
],
[
"Pradhan",
"Sandeep",
""
]
] |
0707.4519 | Jun Ohkubo | Jun Ohkubo | Condensation phenomena with distinguishable particles | 7 pages, 4 figures | Phys. Rev. E. 76, 051108 (2007) | 10.1103/PhysRevE.76.051108 | null | cond-mat.dis-nn cond-mat.stat-mech | null | We study real-space condensation phenomena in a type of classical stochastic
processes (site-particle system), such as zero-range processes and urn models.
We here study a stochastic process in the Ehrenfest class, i.e., particles in a
site are distinguishable. In terms of the statistical mechanical analogue, the
Ehrenfest class obeys the Maxwell-Boltzmann statistics. We analytically clarify
conditions for condensation phenomena in disordered cases in the Ehrenfest
class. In addition, we discuss the preferential urn model as an example of the
disordered urn model. It becomes clear that the quenched disorder property
plays an important role in the occurrence of the condensation phenomenon in the
preferential urn model. It is revealed that the preferential urn model shows
three types of condensation depending on the disorder parameters.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 01:33:17 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Dec 2007 01:09:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ohkubo",
"Jun",
""
]
] |
0707.4520 | Ovidiu Patu | Ovidiu I. Patu, Vladimir E. Korepin, Dmitri V. Averin | Correlation Functions of One-Dimensional Lieb-Liniger Anyons | 19 pages, RevTeX 4 | J. Phys. A: Math. Theor. 40 (2007) 14963-14984 | 10.1088/1751-8113/40/50/004 | null | cond-mat.stat-mech quant-ph | null | We have investigated the properties of a model of 1D anyons interacting
through a $\delta$-function repulsive potential. The structure of the
quasi-periodic boundary conditions for the anyonic field operators and the
many-anyon wavefunctions is clarified. The spectrum of the low-lying
excitations including the particle-hole excitations is calculated for periodic
and twisted boundary conditions. Using the ideas of the conformal field theory
we obtain the large-distance asymptotics of the density and field correlation
function at the critical temperature T=0 and at small finite temperatures. Our
expression for the field correlation function extends the results in the
literature obtained for harmonic quantum anyonic fluids.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 01:43:15 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Mar 2008 02:59:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Patu",
"Ovidiu I.",
""
],
[
"Korepin",
"Vladimir E.",
""
],
[
"Averin",
"Dmitri V.",
""
]
] |
0707.4521 | Shintaro Nomura | Shintaro Nomura and Toshiaki Iitaka | Linear scaling calculation of a n-type GaAs quantum dot | 5 pages, 3 figures | null | 10.1103/PhysRevE.76.037701 | null | cond-mat.mes-hall | null | A linear scale method for calculating electronic properties of large and
complex systems is introduced within a local density approximation. The method
is based on the Chebyshev polynomial expansion and the time-dependent method,
which is tested in calculating the electronic structure of a model n-type GaAs
quantum dot.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 01:52:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nomura",
"Shintaro",
""
],
[
"Iitaka",
"Toshiaki",
""
]
] |
0707.4522 | Ian Agol | Ian Agol | Criteria for virtual fibering | 17 pages, 3 figures; new theorem 7.2; to appear in Journal of
Topology | null | 10.1112/jtopol/jtn003 | null | math.GT math.GR | null | We prove that an irreducible 3-manifold whose fundamental group satisfies a
certain group-theoretic property called RFRS is virtually fibered. As a
corollary, we show that 3-dimensional reflection orbifolds and arithmetic
hyperbolic orbifolds defined by a quadratic form virtually fiber. These include
the Seifert Weber dodecahedral space and the Bianchi orbifolds. Moreover, we
show that a taut sutured compression body has a finite-sheeted cover with a
depth one taut-oriented foliation.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 02:09:53 GMT"
},
{
"version": "v2",
"created": "Sun, 24 Feb 2008 02:20:55 GMT"
}
] | 2014-02-26T00:00:00 | [
[
"Agol",
"Ian",
""
]
] |
0707.4523 | Xian-Hui Ge | Xian-Hui Ge, Sang Pyo Kim | Quantum Entanglement and Teleportation in Higher Dimensional Black Hole
Spacetimes | 15 pages, 10 figures,contents expanded | Class.Quant.Grav.25:075011,2008 | 10.1088/0264-9381/25/7/075011 | null | quant-ph gr-qc hep-ph hep-th | null | We study the properties of quantum entanglement and teleportation in the
background of stationary and rotating curved space-times with extra dimensions.
We show that a maximally entangled Bell state in an inertial frame becomes less
entangled in curved space due to the well-known Hawking-Unruh effect. The
degree of entanglement is found to be degraded with increasing the extra
dimensions. For a finite black hole surface gravity, the observer may choose
higher frequency mode to keep high level entanglement. The fidelity of quantum
teleporation is also reduced because of the Hawking-Unruh effect. We discuss
the fidelity as a function of extra dimensions, mode frequency, black hole mass
and black hole angular momentum parameter for both bosonic and fermionic
resources.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 02:11:34 GMT"
},
{
"version": "v2",
"created": "Wed, 15 Aug 2007 12:42:20 GMT"
},
{
"version": "v3",
"created": "Wed, 31 Oct 2007 12:58:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ge",
"Xian-Hui",
""
],
[
"Kim",
"Sang Pyo",
""
]
] |
0707.4524 | Shiguo Lian | Shiguo Lian | Image Authentication Based on Neural Networks | 16 pages,10 figures, submitted | null | null | null | cs.MM cs.NE | null | Neural network has been attracting more and more researchers since the past
decades. The properties, such as parameter sensitivity, random similarity,
learning ability, etc., make it suitable for information protection, such as
data encryption, data authentication, intrusion detection, etc. In this paper,
by investigating neural networks' properties, the low-cost authentication
method based on neural networks is proposed and used to authenticate images or
videos. The authentication method can detect whether the images or videos are
modified maliciously. Firstly, this chapter introduces neural networks'
properties, such as parameter sensitivity, random similarity, diffusion
property, confusion property, one-way property, etc. Secondly, the chapter
gives an introduction to neural network based protection methods. Thirdly, an
image or video authentication scheme based on neural networks is presented, and
its performances, including security, robustness and efficiency, are analyzed.
Finally, conclusions are drawn, and some open issues in this field are
presented.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 02:27:10 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Lian",
"Shiguo",
""
]
] |
0707.4525 | Abramo Hefez | Abramo Hefez and Marcelo E. Hernandes | Analytic classification of plane branches up to multiplicity 4 | 10 pages, 1 table | null | 10.1016/jsc.2008.09.003 | null | math.AG | null | We perform the analytic classification of plane branches of multiplicity less
or equal than four.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 02:45:21 GMT"
}
] | 2016-01-28T00:00:00 | [
[
"Hefez",
"Abramo",
""
],
[
"Hernandes",
"Marcelo E.",
""
]
] |
0707.4526 | Hao Wei | Hao Wei, Rong-Gen Cai | Statefinder Diagnostic and w-w' Analysis for the Agegraphic Dark Energy
Models without and with Interaction | 11 pages, 4 figures, Latex2e; v2: Phys. Lett. B in press; v3:
published version | Phys.Lett.B655:1-6,2007 | 10.1016/j.physletb.2007.08.066 | null | gr-qc astro-ph hep-th | null | A new dark energy model, named as ``agegraphic dark energy'', has been
proposed by one of us (R. G. Cai) in arXiv:0707.4049, based on the
K\'{a}rolyh\'{a}zy uncertainty relation, which arises from the quantum
mechanics together with general relativity. Then, in arXiv:0707.4052, it has
been extended by including the interaction between the agegraphic dark energy
and the pressureless (dark) matter. In this note, we investigate the agegraphic
dark energy models without and with interaction by means of statefinder
diagnostic and w-w' analysis.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 14:59:50 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 15:58:22 GMT"
},
{
"version": "v3",
"created": "Mon, 8 Oct 2007 18:01:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wei",
"Hao",
""
],
[
"Cai",
"Rong-Gen",
""
]
] |
0707.4527 | Tim Roemer | Winfried Bruns, Robert Koch, Tim Roemer | Gr\"obner bases and Betti numbers of monoidal complexes | 18 pages | Michigan Math. J. 57 (2008), 71-91 | 10.1307/mmj/1220879398 | null | math.AC math.CO | null | In this note we consider monoidal complexes and their associated algebras,
called toric face rings. These rings generalize Stanley-Reisner rings and
affine monoid algebras. We compute initial ideals of the presentation ideal of
a toric face ring, and determine its graded Betti numbers. Our results
generalize celebrated theorems of Hochster in combinatorial commutative
algebra.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 04:00:09 GMT"
}
] | 2021-05-18T00:00:00 | [
[
"Bruns",
"Winfried",
""
],
[
"Koch",
"Robert",
""
],
[
"Roemer",
"Tim",
""
]
] |
0707.4528 | Ajay Ramadoss C. | Ajay C. Ramadoss | Integration over complex manifolds via Hochschild homology | Final version. To appear in Journal of Noncommutative Geometry | J. Noncommut. Geom 3 (2009), no. 1, 27-45 | null | null | math.AG math.QA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Given a holomorphic vector bundle $\cale$ on a connected compact complex
manifold X, [FLS] construct a $\compl$-linear functional $I_{\cale}$ on
$\hh{2n}{\compl}$. This is done by constructing a linear functional on the 0-th
completed Hochschild homology $\choch{0}{(\dif(\cale))}$ of the sheaf of
holomorphic differential operators on $\cale$ using topological quantum
mechanics. They show that this functional is $\int_X$ if $\cale$ has non zero
Euler characteristic. They conjecture that this functional is $\int_X$ for all
$\cale$.
A subsequent work [Ram] by the author proved that the linear functional
$I_{\cale}$ is independent of the vector bundle $\cale$. This note builds upon
the work in [Ram] to prove that $I_{\cale}=\int_X$ for an arbitrary holomorphic
vector bundle $\cale$ on an arbitrary connected compact complex manifold X.
This is done using an argument that is very natural from the geometric point of
view. This argument enables us to extend the construction in [FLS] to a
construction of a linear functional $I_{\cale}$ on
$\text{H}^{2n}_{c}(Y,\compl)$ for an arbitrary holomorphic vector bundle
$\cale$ on an arbitrary connected complex manifold Y and prove that $I_{\cale}
= \int_Y$. We also generalize a result of [Ram] pertaining to "cyclic homology
analogs" of $I_{\cale}$.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 04:11:58 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jun 2008 23:52:38 GMT"
}
] | 2010-09-28T00:00:00 | [
[
"Ramadoss",
"Ajay C.",
""
]
] |
0707.4529 | Tao Zhu | Ji-Rong Ren, Tao Zhu, Yi-Shi Duan | Topological Properties of Spatial Coherence Function | 9 pages | Chin. Phys. Lett.25, 367-370(2008) | 10.1088/0256-307X/25/2/005 | null | physics.optics | null | Topology of the spatial coherence function is considered in details. The
phase singularity (coherence vortices) structures of coherence function are
classified by Hopf index and Brouwer degree in topology. The coherence flux
quantization and the linking of the closed coherence vortices are also studied
from the topological properties of the spatial coherence function.
| [
{
"version": "v1",
"created": "Tue, 31 Jul 2007 04:37:57 GMT"
}
] | 2008-11-07T00:00:00 | [
[
"Ren",
"Ji-Rong",
""
],
[
"Zhu",
"Tao",
""
],
[
"Duan",
"Yi-Shi",
""
]
] |
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