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sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.0930 | Pushpalatha Bhat | Michael Pogwizd, Laura Jane Elgass, Pushpalatha C. Bhat | Bayesian Learning of Neural Networks for Signal/Background
Discrimination in Particle Physics | 3 pages, 4 figures, conference proceedings | null | null | null | physics.data-an | null | Neural networks are used extensively in classification problems in particle
physics research. Since the training of neural networks can be viewed as a
problem of inference, Bayesian learning of neural networks can provide more
optimal and robust results than conventional learning methods. We have
investigated the use of Bayesian neural networks for signal/background
discrimination in the search for second generation leptoquarks at the Tevatron,
as an example. We present a comparison of the results obtained from the
conventional training of feedforward neural networks and networks trained with
Bayesian methods.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:18:02 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Pogwizd",
"Michael",
""
],
[
"Elgass",
"Laura Jane",
""
],
[
"Bhat",
"Pushpalatha C.",
""
]
] |
0707.0931 | Frederic Daigne | F. Daigne (1) and R. Mochkovitch (1) ((1) Institut d'Astrophysique de
Paris and Universite Pierre et Marie Curie, Paris) | The low-luminosity tail of the GRB distribution: the case of GRB 980425 | 10 pages, 7 figures | Astron.Astrophys.465:1-8,2007 | 10.1051/0004-6361:20066080 | null | astro-ph | null | (abridged) The association of GRB 980425 with SN 1998bw at z=0.0085 implies
the existence of a population of GRBs with an isotropic-equivalent luminosity
which is about 10^4 times smaller than in the standard cosmological case. We
investigate two scenarios to explain a weak GRB : a normal (intrinsically
bright) GRB seen off-axis or an intrinsically weak GRB seen on-axis. For each
of these two scenarios, we first derive the conditions to produce a GRB
980425-like event and we then discuss the consequences for the event rate. If
we exclude the possibility that GRB 980425 is an occurence of an extremely rare
event observed by chance during the first eight years of the 'afterglow era',
the first scenario implies that (i) the local rate of standard bright GRBs is
much higher than what is usually expected; (ii) the typical opening angle is
much narrower than what is derived from observations of a break in the
afterglow lightcurve. In addition, we show that the afterglow of GRB 980425 in
this scenario should have been very bright and easily detected. For these
reasons the second scenario appears more realistic. We show that the parameter
space of the internal shock model indeed allows GRB 980425-like events, in
cases where the outflow is only mildly-relativistic and mildly-energetic. The
rate of such weak events in the Universe has to be much higher than the rate of
standard bright GRBs to allow the discovery of GRB 980425 during a short period
of a few years. However it is still compatible with the observations as the
intrinsic weakness of these GRB 980425-like bursts does not allow detection at
cosmological redshift. We finally briefly discuss the consequences of such a
high local rate of GRB 980425-like events for the future prospects of detecting
non-electromagnetic radiation, especially gravitational waves.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 09:35:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Daigne",
"F.",
""
],
[
"Mochkovitch",
"R.",
""
]
] |
0707.0932 | Ezio Vasselli | Roberto Conti, Ezio Vasselli | Extension of automorphisms to C*-crossed products with non-trivial
centre | 19 pages | J. Operator Theory 64, no.2, 417-434 (2010) | null | null | math.OA | null | Given a quasi-special endomorphism $\rho$ of a C*-algebra A with nontrivial
center, we study an extension problem for automorphisms of A to a minimal
cross-product B of A by $\rho$. Exploiting some aspects of the underlying
generalized Doplicher-Roberts duality theory based on Pimsner algebras, an
obstruction to the existence of such extensions is found and described in terms
of sections of a suitable group bundle.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 09:47:38 GMT"
}
] | 2011-11-21T00:00:00 | [
[
"Conti",
"Roberto",
""
],
[
"Vasselli",
"Ezio",
""
]
] |
0707.0933 | Stefania Carpano | S. Carpano, A. M. T. Pollock, A. R. King, J. Wilms, M. Ehle | An ultraluminous supersoft source with a 4 hour modulation in NGC 4631 | 4 pages, 4 figures, accepted as a Letter in Astronomy & Astrophysics | null | 10.1051/0004-6361:20077605 | null | astro-ph | null | Context. Supersoft X-ray sources (SSSs) are characterised by very low
temperatures (< 100 eV). Classical SSSs have bolometric luminosities in the
range of 10^36-10^38 erg/s and are modelled with steady nuclear burning of
hydrogen on the surfaces of white dwarfs. However, several SSSs have been
discovered with much higher luminosities. Their nature is still unclear. Aims.
We report the discovery of a 4h modulation for an ultraluminous SSS in the
nearby edge-on spiral galaxy NGC 4631, observed with XMM-Newton in 2002 June.
Temporal and spectral analysis of the source is performed. Methods. We use a
Lomb-Scargle periodogram analysis for the period search and evaluate the
confidence level using Monte-Carlo simulations. We measure the source
temperature, flux and luminosity through spectral fitting. Results. A
modulation of 4.2+-0.4 h (3 sigma error) was found for the SSS with a
confidence level >99%. Besides dips observed in the light curve, the flux
decreased by a factor of 3 within ~10h. The spectrum can be described with an
absorbed blackbody model with kT~67eV. The absorbed luminosity in the 0.2-2 kev
energy band was 2.7x10^38 erg/sec while the bolometric luminosity was a hundred
time higher (3.2x10^40 erg/s), making the source one of the most luminous of
its class, assuming the best fit model is correct. Conclusions. This source is
another very luminous SSS for which the standard white dwarf interpretation
cannot be applied, unless a strong beaming factor is considered. A stellar-mass
black hole accreting at a super Eddington rate is a more likely interpretation,
where the excess of accreted matter is ejected through a strong optically-thick
outflow. The 4 h modulation could either be an eclipse from the companion star
or the consequence of a warped accretion disk.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 09:53:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Carpano",
"S.",
""
],
[
"Pollock",
"A. M. T.",
""
],
[
"King",
"A. R.",
""
],
[
"Wilms",
"J.",
""
],
[
"Ehle",
"M.",
""
]
] |
0707.0934 | Juan Guti\'errez-Soto | J. Guti\'errez-Soto (GEPI, France), J. Fabregat (OAUV, Spain), J. Suso
(GACE, Spain), J. C. Su\'arez (IAA, Spain), A. Moya (IAA, Spain), R. Garrido
(IAA, Spain), A.-M. Hubert (GEPI, France), M. Floquet (GEPI, France), C.
Neiner (GEPI, France) and Y. Fr\'emat (ROB, Beligum) | Multiperiodic pulsations in the Be stars NW Ser and V1446 Aql | 7 pages, 9 figures, Accepted for publication in Astronomy and
Astrophysics | null | null | null | astro-ph | null | Aims: We present accurate photometric time series of two Be stars: NW Ser and
V1446 Aql. Both stars were observed at the Observatorio de Sierra Nevada
(Granada) in July 2003 with an automatic four-channel Str\"omgren photometer.
We also present a preliminary theoretical study showing that the periodic
variations exhibited by these stars can be due to pulsation.
Methods: An exhaustive Fourier analysis together with a least-square fitting
has been carried out on the time series for all four Str\"omgren bands. Several
independent frequencies and non-periodic trends explain most of the variance. A
theoretical non-adiabatic code applied to stellar models for these stars shows
that g-modes are unstable.
Results: Both stars show rapid variations in amplitude, probably due to a
beating phenomenon. Four significant frequencies have been detected for each
star. Comparison of the observed amplitude ratios for each pulsational
frequency with those calculated from theoretical pulsation codes allows us to
estimate the pulsation modes associated with the different detected
frequencies. NW Ser seems also to show unstable p-modes and thus could be one
of the newly discovered $\beta$ Cephei and SPB hybrid stars. Further
spectroscopic observations are planned to study the stability of the detected
frequencies.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:03:59 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Gutiérrez-Soto",
"J.",
"",
"GEPI, France"
],
[
"Fabregat",
"J.",
"",
"OAUV, Spain"
],
[
"Suso",
"J.",
"",
"GACE, Spain"
],
[
"Suárez",
"J. C.",
"",
"IAA, Spain"
],
[
"Moya",
"A.",
"",
"IAA, Spain"
],
[
"Garrido",
"R.",
"",
"IAA, Spain"
],
[
"Hubert",
"A. -M.",
"",
"GEPI, France"
],
[
"Floquet",
"M.",
"",
"GEPI, France"
],
[
"Neiner",
"C.",
"",
"GEPI, France"
],
[
"Frémat",
"Y.",
"",
"ROB, Beligum"
]
] |
0707.0935 | Nikolai Erkaev V. | N.V. Erkaev, V.S. Semenov, H.K. Biernat | Magnetic double gradient instability and flapping waves in a current
sheet | 4 pages, 4 figures, submitted to Phys. Rev. Lett | null | 10.1103/PhysRevLett.99.235003 | null | physics.space-ph physics.plasm-ph | null | A new kind of magnetohydrodynamic instability and waves are analyzed for a
current sheet in the presence of a small normal magnetic field component
varying along the sheet. These waves and instability are related to existence
of two gradients of the tangential and normal magnetic field components along
the normal and tangential directions with respect to the current sheet. The
current sheet can be stable or unstable if the multiplication of two magnetic
gradients is positive or negative. In the stable region, the kink-like wave
mode is interpreted as so called flapping waves observed in the Earth's
magnetotail current sheet. The kink wave group velocity estimated for the
Earth's current sheet is of the order of a few tens kilometers per second. This
is in good agreement with the observations of the flapping motions of the
magnetotail current sheet.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:55:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Erkaev",
"N. V.",
""
],
[
"Semenov",
"V. S.",
""
],
[
"Biernat",
"H. K.",
""
]
] |
0707.0936 | Chao-Yang Pang | Chao-Yang Pang, and Cong-Bao Ding and Ben-Qiong Hu | Quantum Pattern Recognition of Classical Signal | 8 papges, 1 figures | null | null | null | quant-ph | null | It's the key research topic of signal processing that recognizing genuine
targets real time from the disturbed signal which has giant amount of data. A
quantum algorithm for pattern recognition of classical signal which has time
complexity O(sqrt(N)) is presented in this paper.
Key Words: Pattern recognition, Grover's algorithm, Rotation on subspace
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:35:34 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Sep 2007 14:12:20 GMT"
}
] | 2007-09-04T00:00:00 | [
[
"Pang",
"Chao-Yang",
""
],
[
"Ding",
"Cong-Bao",
""
],
[
"Hu",
"Ben-Qiong",
""
]
] |
0707.0937 | Roberto Mignani | R. P. Mignani (UCL-MSSL), A. De Luca (INAF-Iasf), S. Zaggia
(INAF-Oap), D. Sester, A. Pellizzoni, S. Mereghetti, P. A. Caraveo
(IASF-Inaf) | VLT observations of the Central Compact Object in the Vela Jr. supernova
remnant | 8 pages, 4 figures, A&Aaccepted | null | 10.1051/0004-6361:20077768 | null | astro-ph | null | X-ray observations have unveiled the existence of enigmatic point-like
sources at the center of young (a few kyrs) supernova remnants. These sources,
known as Central Compact Objects (CCOs), are thought to be neutron stars
produced by the supernova explosion, although their X-ray phenomenology makes
them markedly different from all the other young neutron stars discovered so
far.The aim of this work is to search for the optical/IR counterpart of the
Vela Junior CCO and to understand the nature of the associated Halpha nebula
discovered by Pellizzoni et al. (2002).}{We have used deep optical (R band) and
IR (J,H,Ks bands) observations recently performed by our group with the ESO VLT
to obtain the first deep, high resolution images of the field with the goal of
resolving the nebula structure and pinpointing a point-like source possibly
associated with the neutron star.Our R-band image shows that both the nebula's
flux and its structure are very similar to the Halpha ones, suggesting that the
nebula spectrum is dominated by pure Halpha line emission. However, the nebula
is not detected in our IR observations, whick makes it impossible to to
constrain its spectrum. A faint point-like object (J>22.6, H~21.6, Ks ~ 21.4)
compatible with the neutron star's Chandra X-ray position is detected in our IR
images (H and Ks) but not in the optical one (R > 25.6), where it is buried by
the nebula background. The nebula is most likely a bow-shock produced by the
neutron star motion through the ISM or, alternatively, a photo-ionization
nebula powered by UV radiation from a hot neutron star.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 09:58:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mignani",
"R. P.",
"",
"UCL-MSSL"
],
[
"De Luca",
"A.",
"",
"INAF-Iasf"
],
[
"Zaggia",
"S.",
"",
"INAF-Oap"
],
[
"Sester",
"D.",
"",
"IASF-Inaf"
],
[
"Pellizzoni",
"A.",
"",
"IASF-Inaf"
],
[
"Mereghetti",
"S.",
"",
"IASF-Inaf"
],
[
"Caraveo",
"P. A.",
"",
"IASF-Inaf"
]
] |
0707.0938 | Timothy H. Boyer | Timothy H. Boyer | Scaling Symmetries of Scatterers of Classical Zero-Point Radiation | 13 pages | J. Phys. A: Math. Theor. 40, 9635-9642 (2007) | 10.1088/1751-8113/40/31/031 | null | physics.class-ph physics.gen-ph | null | Classical radiation equilibrium (the blackbody problem) is investigated by
the use of an analogy. Scaling symmetries are noted for systems of classical
charged particles moving in circular orbits in central potentials V(r)=-k/r^n
when the particles are held in uniform circular motion against radiative
collapse by a circularly polarized incident plane wave. Only in the case of a
Coulomb potential n=1 with fixed charge e is there a unique scale-invariant
spectrum of radiation versus frequency (analogous to zero-point radiation)
obtained from the stable scattering arrangement. These results suggest that
non-electromagnetic potentials are not appropriate for discussions of classical
radiation equilibrium.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:16:03 GMT"
}
] | 2010-05-17T00:00:00 | [
[
"Boyer",
"Timothy H.",
""
]
] |
0707.0939 | Francisco Martin Cabrera | Francisco Martin Cabrera and Andrew Swann | The intrinsic torsion of almost quaternion-Hermitian manifolds | 38 pages | null | null | null | math.DG | null | We study the intrinsic torsion of almost quaternion-Hermitian manifolds via
the exterior algebra. In particular, we show how it is determined by particular
three-forms formed from simple combinations of the exterior derivatives of the
local Kaehler forms. This gives a practical method to compute the intrinsic
torsion and is applied in a number of examples. In addition we find simple
characterisations of HKT and QKT geometries entirely in the exterior algebra
and compute how the intrinsic torsion changes under a twist construction.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:22:28 GMT"
}
] | 2020-11-20T00:00:00 | [
[
"Cabrera",
"Francisco Martin",
""
],
[
"Swann",
"Andrew",
""
]
] |
0707.0940 | Giovanni Forni | Giovanni Forni | Sobolev regularity of solutions of the cohomological equation | 119 pages | Ergod. Th. Dynam. Sys. 41 (2021) 685-789 | 10.1017/etds.2019.108 | null | math.DS math.AP | null | We refine the theory of the cohomological equation for translation flows on
higher genus surfaces with the goal of proving optimal results on the Sobolev
regularity of solutions and of distributional obstructions. For typical
translation surfaces our results are sharp and we find the expected relation
between the regularity of the distributional obstructions and the Lyapunov
exponents of the Kontsevich-Zorich renormalization cocycle. As a consequence we
exactly determine the dimension of the space of obstructions in each Sobolev
regularity class in terms of the Kontsevich-Zorich exponents. For a fixed
arbitrary translation surface and a typical direction, our results are probably
not optimal but are the best which can be achieved with the available harmonic
analysis techniques we have introduced in an earlier paper.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:50:36 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 16:09:30 GMT"
}
] | 2021-02-03T00:00:00 | [
[
"Forni",
"Giovanni",
""
]
] |
0707.0941 | Iosif Galanakis | I. Galanakis | Effect of surfaces and interfaces on the electronic, magnetic and
gap-related properties of the half-metal Co$_2$MnSn | 5 pages, 4 figures Prepared for a special issue of Journal of
Computational and Theoretical Nanoscience on Low-Dimensional Systems | Journal of Computational and Theoretical Nanoscience 7, 474 (2010) | null | null | cond-mat.mtrl-sci | null | We present state-of-the-art electronic structure calculations for the
Co$_2$MnSn full-Heusler alloy. We show that in its bulk form it is a
half-metallic ferromagnet with the Fermi level being located within a tiny gap
of the minority-spin density of states. Moreover the alloy shows the
Slater-Pauling behavior with a total spin magnetic moment in the unit cell of 5
$\mu_B$. In the case of the (001) surfaces, the broken bonds at the surface
form a minority band pinned exactly at the Fermi level destroying the
half-metallicity. Our calculations reveal that both the interfaces with the
non-magnetic metal V and the semiconductor InAs are no more half-metallic due
to the different environment of the atoms of the half-metal at the interface.
These interface states although localized only at the first few interface
layers can become conducting when coupled to defect states and kill the
spin-polarization of the current injected from the half-metal into the
semiconductor or the non-magnetic metallic spacer.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:28:25 GMT"
}
] | 2011-01-28T00:00:00 | [
[
"Galanakis",
"I.",
""
]
] |
0707.0942 | Leszek Soko{\l}owski | Leszek M. Sokolowski | Metric gravity theories and cosmology:II. Stability of a ground state in
f(R) theories | A modified and expanded version of a second part of the paper which
previously appeared as gr-qc/0702097v1. The first, modified part is now
published as gr-qc/0702097v2 and as a separate paper in Class. Qu. Grav. The
present paper matches the published version | Class.Quant.Grav.24:3713-3734,2007 | 10.1088/0264-9381/24/14/011 | null | gr-qc | null | A fundamental criterion of viability of any gravity theory is existence of a
stable ground-state solution being either Minkowski, dS or AdS space. Stability
of the ground state is independent of which frame is physical. In general, a
given theory has multiple ground states and splits into independent physical
sectors. All metric gravity theories with the Lagrangian being a function of
Ricci tensor are dynamically equivalent to Einstein gravity with a source and
this allows us to study the stability problem using methods developed in GR. We
apply these methods to f(R) theories. As is shown in 13 cases of Lagrangians
the stability criterion works simply and effectively whenever the curvature of
the ground state is determined. An infinite number of gravity theories have a
stable ground state and further viability criteria are necessary.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:31:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sokolowski",
"Leszek M.",
""
]
] |
0707.0943 | Oleg Dalkarov | O.D. Dalkarov | On the nuclear reactions with participation of near-threshold baryon
resonances | null | null | null | null | nucl-th | null | The main features of nuclear reactions with participation of baryon
resonances ($\Delta$(1232), S(1535) and $\Lambda$(1405)), which are interpreted
as a manifestation of the bound states of nucleus and corresponding meson are
discussed.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:38:22 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Dalkarov",
"O. D.",
""
]
] |
0707.0944 | Fredrik Schoeier | F. L. Schoeier, J. Bast, H. Olofsson, M. Lindqvist | The abundance of SiS in circumstellar envelopes around AGB stars | Accepted for publication in A&A (14 pages, 7 figures) | null | 10.1051/0004-6361:20077887 | null | astro-ph | null | New SiS multi-transition (sub-)millimetre line observations of a sample of
AGB stars with varying photospheric C/O-ratios and mass-loss rates are
presented. A combination of low- and high-energy lines are important in
constraining the circumstellar distribution of SiS molecules. A detailed
radiative transfer modelling of the observed SiS line emission is performed,
including the effect of thermal dust grains in the excitation analysis. We find
that the circumstellar fractional abundance of SiS in these environments has a
strong dependence on the photospheric C/O-ratio as expected from chemical
models. The carbon stars (C/O>1) have a mean fractional abundance of 3.1E-6,
about an order of magnitude higher than found for the M-type AGB stars (C/O<1)
where the mean value is 2.7E-7. These numbers are in reasonable agreement with
photospheric LTE chemical models. SiS appears to behave similar to SiO in terms
of photodissociation in the outer part of the circumstellar envelope. In
contrast to previous results for the related molecule SiO, there is no strong
correlation of the fractional abundance with density in the CSE, as would be
the case if freeze-out onto dust grains were important. However, possible
time-variability of the line emission in the lower J transitions and the
sensitivity of the line emission to abundance gradients in the inner part of
the CSE may mask a correlation with the density of the wind. There are
indications that the SiS fractional abundance could be significantly higher
closer to the star which, at least in the case of M-type AGB stars, would
require non-equilibrium chemical processes.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:45:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Schoeier",
"F. L.",
""
],
[
"Bast",
"J.",
""
],
[
"Olofsson",
"H.",
""
],
[
"Lindqvist",
"M.",
""
]
] |
0707.0945 | Luca Biferale | F. Diotallevi, L. Biferale, S. Chibbaro, A. Lamura, G. Pontrelli, M.
Sbragaglia, S. Succi and F. Toschi | Capillary filling using Lattice Boltzmann Equations: the case of
multi-phase flows | null | null | null | null | nlin.CG | null | We present a systematic study of capillary filling for multi-phase flows by
using mesoscopic lattice Boltzmann models describing a diffusive interface
moving at a given contact angle with respect to the walls. We compare the
numerical results at changing the density ratio between liquid and gas phases
and the ratio between the typical size of the capillary and the interface
width. It is shown that numerical results yield quantitative agreement with the
Washburn law when both ratios are large, i.e. as the hydrodynamic limit of a
infinitely thin interface is approached. We also show that in the initial stage
of the filling process, transient behaviour induced by inertial effects and
``vena contracta'' mechanisms, may induce significant departure from the
Washburn law. Both effects are under control in our lattice Boltzmann equation
and in good agreement with the phenomenology of capillary filling.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 10:52:34 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Diotallevi",
"F.",
""
],
[
"Biferale",
"L.",
""
],
[
"Chibbaro",
"S.",
""
],
[
"Lamura",
"A.",
""
],
[
"Pontrelli",
"G.",
""
],
[
"Sbragaglia",
"M.",
""
],
[
"Succi",
"S.",
""
],
[
"Toschi",
"F.",
""
]
] |
0707.0946 | Carlos Merino | C. Merino, C. Pajares, and Yu. M. Shabelski | Open Charm Production in pp and Heavy Ion Collisions in QCD | Talk given at the Ninth Workshop on Non-Perturbative Quantum
Chromodynamics, Paris (France), June 4th-8th, 2007 (8 pages and 3 figures) | ECONFC0706044:20,2007 | null | null | hep-ph | null | The RHIC data on charm production are compared with the kT-factorization
approach predictions, both standard NLO QCD and FONLL. The calculated results
underestimate the STAR Collaboration data. The role of possible nuclear effects
is discussed.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:02:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Merino",
"C.",
""
],
[
"Pajares",
"C.",
""
],
[
"Shabelski",
"Yu. M.",
""
]
] |
0707.0947 | Mohsen Shadmehri | Mohsen Shadmehri, Turlough P. Downes | Kelvin-Helmholtz instability in a weakly ionized layer | Accepted for publication in Astrophysics & Space Science | Astrophys.SpaceSci.312:79-84,2007 | 10.1007/s10509-007-9655-9 | null | astro-ph | null | We study the linear theory of Kelvin-Helmholtz instability in a layer of ions
and neutrals with finite thickness. In the short wavelength limit the thickness
of the layer has a negligible effect on the growing modes. However,
perturbations with wavelength comparable to layer's thickness are significantly
affected by the thickness of the layer. We show that the thickness of the layer
has a stabilizing effect on the two dominant growing modes. Transition between
the modes not only depends on the magnetic strength, but also on the thickness
of the layer.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:05:54 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 11:48:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Shadmehri",
"Mohsen",
""
],
[
"Downes",
"Turlough P.",
""
]
] |
0707.0948 | Nuno Dias | Nuno Costa Dias, Andrea Posilicano, Joao Nuno Prata | Self-adjoint, globally defined Hamiltonian operators for systems with
boundaries | 25 pages, published version | Communications on Pure and Applied Analysis, 10, 6 (2011)
1687-1706 | null | null | math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | For a general self-adjoint Hamiltonian operator $H_0$ on the Hilbert space
$L^2(\RE^d)$, we determine the set of all self-adjoint Hamiltonians $H$ on
$L^2(\RE^d)$ that dynamically confine the system to an open set $\Omega \subset
\RE^d$ while reproducing the action of $ H_0$ on an appropriate operator
domain. In the case $H_0=-\Delta +V$ we construct these Hamiltonians explicitly
showing that they can be written in the form $H=H_0+ B$, where $B$ is a
singular boundary potential and $H$ is self-adjoint on its maximal domain. An
application to the deformation quantization of one-dimensional systems with
boundaries is also presented.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:18:18 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Mar 2009 23:30:17 GMT"
},
{
"version": "v3",
"created": "Tue, 11 May 2010 00:30:57 GMT"
},
{
"version": "v4",
"created": "Thu, 12 Apr 2012 01:01:02 GMT"
}
] | 2012-04-13T00:00:00 | [
[
"Dias",
"Nuno Costa",
""
],
[
"Posilicano",
"Andrea",
""
],
[
"Prata",
"Joao Nuno",
""
]
] |
0707.0949 | Mikhail Zobov | Eugene Levichev, Pavel Piminov (BINP, Novosibirsk), Pantaleo Raimondi,
Mikhail Zobov (INFN LNF) | Dynamic Aperture Optimization for the DAFNE Upgrade | 12 pages, 10 figues, 3 tables | null | null | LNF-07/15 (IR) and DAFNE-Note-69 | physics.acc-ph | null | Recently proposed novel idea of "crabbed waist" beam-beam collisions will be
tested at DAFNE during the collider run for the Siddharta experiment. In order
to achieve the goal luminosity, large dynamic aperture is a matter of primary
importance. A new method of a dynamic aperture optimization based on
step-by-step chromaticity compensation with choosing the "best" sextupole pair
at each step was applied to the DAFNE upgrade lattice. Several tune points were
considered taking into account both high luminosity and large dynamic aperture.
Algorithm and results of optimization will be presented.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:31:49 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Levichev",
"Eugene",
"",
"BINP, Novosibirsk"
],
[
"Piminov",
"Pavel",
"",
"BINP, Novosibirsk"
],
[
"Raimondi",
"Pantaleo",
"",
"INFN LNF"
],
[
"Zobov",
"Mikhail",
"",
"INFN LNF"
]
] |
0707.0950 | Rajeev Rawat | Pallavi Kushwaha, R Rawat, P Chaddah | Field induced magnetic transition and metastability in Co substituted
$Mn_{2}Sb$ | 10 pages, 8 figures | J. Phys.: Condens. Matter 20 (2008) 022204. | 10.1088/0953-8984/20/02/022204 | null | cond-mat.str-el | null | A detailed investigation of first order ferrimagnetic (FRI) to
antiferromagnetic (AFM) transition in Co (15%) doped $Mn_2Sb$ is carried out.
These measurements demonstrate anomalous thermomagnetic irreversibility and
glass-like frozen FRI phase at low temperatures. The irreversibility arising
between the supercooling and superheating spinodals is distinguised in an
ingenious way from the irreversibility arising due to kinetic arrest. Field
annealing measurements shows reentrant FRI-AFM-FRI transition with increasing
temperature. These measurements also show that kinetic arrest band and
supercooling band are anitcorrelated i.e regions which are kinetically arrested
at higher temperature have lower supercooling temperature and vice versa.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:33:57 GMT"
}
] | 2007-12-18T00:00:00 | [
[
"Kushwaha",
"Pallavi",
""
],
[
"Rawat",
"R",
""
],
[
"Chaddah",
"P",
""
]
] |
0707.0951 | Saibal Ray | F. Rahaman, Saibal Ray, M. Kalam and M. Sarker | Do Solar system tests permit higher dimensional general relativity? | 13 Latex pages and 11 figures with a few changes in the text and
reference | Int J Theor Phys (2009) 48: 3124--3138 | 10.1007/s10773-009-0110-2 | null | gr-qc | null | We perform a survey whether higher dimensional Schwarzschild space-time is
compatible with some of the solar system phenomena. As a test we examine five
well known solar system effects, viz., (1) Perihelion shift, (2) Bending of
light, (3) Gravitational redshift, (4) Gravitational time delay and (5) Motion
of test particle in the framework of general relativity with higher dimensions.
It is shown that the results related to all these physical phenomena are mostly
incompatible with the higher dimensional version of general relativity except
that of Motion of test particle. We compare all these results with the
available data in the literature.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:39:12 GMT"
},
{
"version": "v2",
"created": "Sat, 7 Jul 2007 17:48:37 GMT"
}
] | 2009-10-21T00:00:00 | [
[
"Rahaman",
"F.",
""
],
[
"Ray",
"Saibal",
""
],
[
"Kalam",
"M.",
""
],
[
"Sarker",
"M.",
""
]
] |
0707.0952 | Robert Mochkovitch | F. Genet, F. Daigne, R. Mochkovitch | The rise of the afterglow in GRB 050820a | 6 pages, 9 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20066160 | null | astro-ph | null | The early optical afterglow of GRB 050820a recorded by the RAPTOR telescope
shows both a contribution from the prompt emission and the initial rise of the
afterglow. It is therefore well-suited for the study of the dynamical evolution
of the GRB ejecta when it first undergoes the decelerating effect of the
environment. This is a complex phase where the internal, reverse, and forward
shocks can all be present simultaneously. We have developed a simplified model
that can follow these different shocks in an approximate, but self-consistent
way. It is applied to the case of GRB 050820a to obtain the prompt and
afterglow light curves. We show that the rise of the afterglow during the
course of the prompt emission has some important consequences. The reverse
shock propagates back into the ejecta before internal shocks are completed,
which affects the shape of the gamma-ray profile. We get the best results when
the external medium has a uniform density, but obtaining a simultaneous fit of
the prompt and afterglow emission is not easy. We discuss a few possibilities
that could help to improve this situation.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:43:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Genet",
"F.",
""
],
[
"Daigne",
"F.",
""
],
[
"Mochkovitch",
"R.",
""
]
] |
0707.0953 | Jean-Luc Marichal | Jean-Luc Marichal | Weighted lattice polynomials of independent random variables | 14 pages | Discrete Applied Mathematics 156 (5) (2008) 685-694 | null | null | math.PR math.RA | null | We give the cumulative distribution functions, the expected values, and the
moments of weighted lattice polynomials when regarded as real functions of
independent random variables. Since weighted lattice polynomial functions
include ordinary lattice polynomial functions and, particularly, order
statistics, our results encompass the corresponding formulas for these
particular functions. We also provide an application to the reliability
analysis of coherent systems.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 11:44:53 GMT"
}
] | 2008-02-19T00:00:00 | [
[
"Marichal",
"Jean-Luc",
""
]
] |
0707.0954 | Kazushi Aoyama | Kazushi Aoyama, Ryusuke Ikeda | Strong Coupling Correction in Superfluid $^3$He in Aerogel | 19 pages, 9 figures, Accepted for publication in Phys. Rev. B | null | 10.1007/s10909-007-9487-6 | null | cond-mat.supr-con cond-mat.str-el | null | Effects of impurity scatterings on the strong coupling (SC) contribution,
stabilizing the ABM (axial) pairing state, to the quartic term of the
Ginzburg-Landau (GL) free energy of superfluid $^3$He are theoretically studied
to examine recent observations suggestive of an anomalously small SC effect in
superfluid $^3$He in aerogels. To study the SC corrections, two approaches are
used. One is based on a perturbation in the short-range repulsive interaction,
and the other is a phenomenological approach used previously for the bulk
liquid by Sauls and Serene [Phys.Rev.B 24, 183 (1981)]. It is found that the
impurity scattering favors the BW pairing state and shrinks the region of the
ABM pairing state in the T-P phase diagram. In the phenomenological approach,
the resulting shrinkage of the ABM region is especially substantial and, if
assuming an anisotropy over a large scale in aerogel, leads to justifying the
phase diagrams determined experimentally.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 12:06:30 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 01:17:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Aoyama",
"Kazushi",
""
],
[
"Ikeda",
"Ryusuke",
""
]
] |
0707.0955 | Eric Buffenoir | Eric Buffenoir (LPTA), Philippe Roche (LPTA), V\'eronique Terras
(LPTA) | Universal Vertex-IRF Transformation for Quantum Affine Algebras | 58 pages | null | null | null | math-ph math.MP math.QA | null | We construct a universal Vertex-IRF transformation between Vertex type
universal solution and Face type universal solution of the quantum dynamical
Yang-Baxter equation. This universal Vertex-IRF transformation satisfies the
generalized coBoundary equation and is an extension of our previous work to the
quantum affine $U_q(A^{(1)}_r)$ case. This solution has a simple Gauss
decomposition which is constructed using Sevostyanov's characters of twisted
quantum Borel algebras. We show that the evaluation of this universal solution
in the evaluation representation of $U_q(A_1^{(1)})$ gives the standard
Baxter's transformation between the 8-Vertex model and the IRF height model.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 12:19:04 GMT"
}
] | 2007-07-10T00:00:00 | [
[
"Buffenoir",
"Eric",
"",
"LPTA"
],
[
"Roche",
"Philippe",
"",
"LPTA"
],
[
"Terras",
"Véronique",
"",
"LPTA"
]
] |
0707.0956 | Lothar M\"uhlbacher | Lothar M\"uhlbacher and Eran Rabani | Real-time path integral approach to nonequilibrium many-body quantum
system | 5 pages, 2 figures | null | 10.1103/PhysRevLett.100.176403 | null | cond-mat.mes-hall cond-mat.stat-mech | null | A real-time path integral Monte Carlo approach is developed to study the
dynamics in a many-body quantum system until reaching a nonequilibrium
stationary state. The approach is based on augmenting an exact reduced equation
for the evolution of the system in the interaction picture which is amenable to
an efficient path integral (worldline) Monte Carlo approach. Results obtained
for a model of inelastic tunneling spectroscopy reveal the applicability of the
approach to a wide range of physically important regimes, including high
(classical) and low (quantum) temperatures, and weak (perturbative) and strong
electron-phonon couplings.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 12:23:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mühlbacher",
"Lothar",
""
],
[
"Rabani",
"Eran",
""
]
] |
0707.0957 | Andrea Fuster | A. Coley, A. Fuster and S. Hervik | Supergravity solutions with constant scalar invariants | 12 pages; to appear in IJMPA | null | null | NIKHEF/2007-016 | hep-th gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study a class of constant scalar invariant (CSI) spacetimes, which belong
to the higher-dimensional Kundt class, that are solutions of supergravity. We
review the known CSI supergravity solutions in this class and we explicitly
present a number of new exact CSI supergravity solutions, some of which are
Einstein.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 12:29:38 GMT"
},
{
"version": "v2",
"created": "Wed, 17 Dec 2008 08:27:00 GMT"
}
] | 2008-12-17T00:00:00 | [
[
"Coley",
"A.",
""
],
[
"Fuster",
"A.",
""
],
[
"Hervik",
"S.",
""
]
] |
0707.0958 | Ronaldo da Silva | R. Da Silva, S. Udry, F. Bouchy, C. Moutou, M. Mayor, J.-L. Beuzit, X.
Bonfils, X. Delfosse, M. Desort, T. Forveille, F. Galland, G. Hebrard, A.-M.
Lagrange, B. Loeillet, C. Lovis, F. Pepe, C. Perrier, F. Pont, D. Queloz,
N.C. Santos, D. Segransan, J.-P. Sivan, A. Vidal-Madjar, and S. Zucker | Elodie metallicity-biased search for transiting Hot Jupiters IV.
Intermediate period planets orbiting the stars HD43691 and HD132406 | 6 pages, 4 figures, to be published in A&A | null | 10.1051/0004-6361:20077314 | null | astro-ph | null | We report here the discovery of two planet candidates as a result of our
planet-search programme biased in favour of high-metallicity stars, using the
ELODIE spectrograph at the Observatoire de Haute Provence. One of them has a
minimum mass m_2\sin{i} = 2.5 M_Jup and is orbiting the metal-rich star HD43691
with period P = 40 days and eccentricity e = 0.14. The other planet has a
minimum mass m_2\sin{i} = 5.6 M_Jup and orbits the slightly metal-rich star
HD132406 with period P = 974 days and eccentricity e = 0.34. Both stars were
followed up with additional observations using the new SOPHIE spectrograph that
replaces the ELODIE instrument, allowing an improved orbital solution for the
systems.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:17:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Da Silva",
"R.",
""
],
[
"Udry",
"S.",
""
],
[
"Bouchy",
"F.",
""
],
[
"Moutou",
"C.",
""
],
[
"Mayor",
"M.",
""
],
[
"Beuzit",
"J. -L.",
""
],
[
"Bonfils",
"X.",
""
],
[
"Delfosse",
"X.",
""
],
[
"Desort",
"M.",
""
],
[
"Forveille",
"T.",
""
],
[
"Galland",
"F.",
""
],
[
"Hebrard",
"G.",
""
],
[
"Lagrange",
"A. -M.",
""
],
[
"Loeillet",
"B.",
""
],
[
"Lovis",
"C.",
""
],
[
"Pepe",
"F.",
""
],
[
"Perrier",
"C.",
""
],
[
"Pont",
"F.",
""
],
[
"Queloz",
"D.",
""
],
[
"Santos",
"N. C.",
""
],
[
"Segransan",
"D.",
""
],
[
"Sivan",
"J. -P.",
""
],
[
"Vidal-Madjar",
"A.",
""
],
[
"Zucker",
"S.",
""
]
] |
0707.0959 | Giuliana Fiorentino | G. Fiorentino, M. Marconi, I. Musella, F. Caputo | Classical Cepheid Pulsation Models. XI. Effects of convection and
chemical composition on the Period-Luminosity and Period-Wesenheit relations | 20 pages, 15 figures | null | 10.1051/0004-6361:20077587 | null | astro-ph | null | In spite of the relevance of Classical Cepheids as primary distance
indicators, a general consensus on the dependence of the Period-Luminosity (PL)
relation on the Cepheid chemical composition has not been achieved yet. From
the theoretical point of view, our previous investigations were able to
reproduce some empirical tests for suitable assumptions on the helium to metal
relative enrichment, but those results relied on specific assumptions
concerning the Mass-Luminosity relation and the efficiency of the convective
transfer in the pulsating envelopes. In this paper, we investigate the effects
of the assumed value of the mixing length parameter l/Hp on the pulsation
properties and we release the assumption of a fixed Mass-Luminosity relation.
As a whole, we show that our pulsation relations appear fully consistent with
the observed properties of Galactic and Magellanic Cloud Cepheids, supporting
the predicted steepening and brightening of the PL relations when moving from
metal-rich to metal-poor variables. Moreover, we show that the distances
inferred by the predicted PW relations agree with recently measured
trigonometric parallaxes, whereas they suggest a correction to the values based
on the Infrared Surface Brightness technique, as already found from an
independent method. Finally, also the pulsation metal contents suggested by the
predicted PW relations appear in statistical agreement with spectroscopic
[Fe/H] measurements.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 12:33:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fiorentino",
"G.",
""
],
[
"Marconi",
"M.",
""
],
[
"Musella",
"I.",
""
],
[
"Caputo",
"F.",
""
]
] |
0707.0960 | Yao Cheng | Yao Cheng and Bing Xia | Rhodium Mossbauer Superradiance of Observable Gravitational Effect | Revised collection including 0707.0960, 0707.2620, and 0706.2628 | null | null | null | quant-ph gr-qc physics.atom-ph | null | We summarize the experimental observations of three case studies on the
long-lived rhodium Mossbauer Effect. Extraordinary observations reported in
this work manifest the open-up of photonic band gap in analogy to the
superconducting gap. Observable gravitational effect is manifested by the
superradiance of different sample orientations corresponding to the earth
gravity. These observations are of potential importance for detecting
gravitational waves and development of the two-photon gamma laser.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 12:52:06 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Jul 2007 03:35:10 GMT"
},
{
"version": "v3",
"created": "Sun, 18 Nov 2007 07:38:21 GMT"
}
] | 2007-11-18T00:00:00 | [
[
"Cheng",
"Yao",
""
],
[
"Xia",
"Bing",
""
]
] |
0707.0961 | John Hammersley | John Hammersley | A critical dimension for the stability of perfect fluid spheres of
radiation | 18 pages, 5 figures; v2 reference and footnote added; v3 slight
reordering of content, new section added with further analysis; v4 Final
version - small changes, including a new title, accepted for publication in
CQG | null | 10.1088/0264-9381/25/20/205010 | null | hep-th gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | An analysis of radiating perfect fluid models with asymptotically AdS
boundary conditions is presented. Such scenarios consist of a spherical gas of
radiation (a "star") localised near the centre of the spacetime due to the
confining nature of the AdS potential. We consider the variation of the total
mass of the star as a function of the central density, and observe that for
large enough dimensionality, the mass increases monotonically with the density.
However in the lower dimensional cases, oscillations appear, indicating that
the perfect fluid model of the star is becoming unrealistic. We find the
critical dimension separating these two regimes to be eleven.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 18:49:13 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 15:08:01 GMT"
},
{
"version": "v3",
"created": "Thu, 24 Apr 2008 16:54:45 GMT"
},
{
"version": "v4",
"created": "Sun, 31 Aug 2008 12:06:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hammersley",
"John",
""
]
] |
0707.0962 | Massimiliano Esposito | Massimiliano Esposito, Upendra Harbola and Shaul Mukamel | Entropy fluctuation theorems in driven open systems: application to
electron counting statistics | Version accepted in Phys. Rev. E | Phys. Rev. E 76, 031132 (2007) | 10.1103/PhysRevE.76.031132 | null | cond-mat.stat-mech | null | The total entropy production generated by the dynamics of an externally
driven systems exchanging energy and matter with multiple reservoirs and
described by a master equation is expressed as the sum of three contributions,
each corresponding to a distinct mechanism for bringing the system out of
equilibrium: nonequilibrium initial conditions, external driving, and breaking
of detailed balance. We derive three integral fluctuation theorems (FTs) for
these contributions and show that they lead to the following universal
inequality: an arbitrary nonequilibrium transformation always produces a change
in the total entropy production greater or equal than the one produced if the
transformation is done very slowly (adiabatically). Previously derived
fluctuation theorems can be recovered as special cases. We show how these FTs
can be experimentally tested by performing the counting statistics of the
electrons crossing a single level quantum dot coupled to two reservoirs with
externally varying chemical potentials. The entropy probability distributions
are simulated for driving protocols ranging from the adiabatic to the sudden
switching limit.
| [
{
"version": "v1",
"created": "Thu, 5 Jul 2007 23:57:14 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Sep 2007 13:07:22 GMT"
}
] | 2010-03-01T00:00:00 | [
[
"Esposito",
"Massimiliano",
""
],
[
"Harbola",
"Upendra",
""
],
[
"Mukamel",
"Shaul",
""
]
] |
0707.0963 | Emanuel Knill | E. Knill, D. Leibfried, R. Reichle, J. Britton, R. B. Blakestad, J. D.
Jost, C. Langer, R. Ozeri, S. Seidelin, and D. J. Wineland | Randomized Benchmarking of Quantum Gates | 13 pages | null | 10.1103/PhysRevA.77.012307 | null | quant-ph | null | A key requirement for scalable quantum computing is that elementary quantum
gates can be implemented with sufficiently low error. One method for
determining the error behavior of a gate implementation is to perform process
tomography. However, standard process tomography is limited by errors in state
preparation, measurement and one-qubit gates. It suffers from inefficient
scaling with number of qubits and does not detect adverse error-compounding
when gates are composed in long sequences. An additional problem is due to the
fact that desirable error probabilities for scalable quantum computing are of
the order of 0.0001 or lower. Experimentally proving such low errors is
challenging. We describe a randomized benchmarking method that yields estimates
of the computationally relevant errors without relying on accurate state
preparation and measurement. Since it involves long sequences of randomly
chosen gates, it also verifies that error behavior is stable when used in long
computations. We implemented randomized benchmarking on trapped atomic ion
qubits, establishing a one-qubit error probability per randomized pi/2 pulse of
0.00482(17) in a particular experiment. We expect this error probability to be
readily improved with straightforward technical modifications.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 18:44:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Knill",
"E.",
""
],
[
"Leibfried",
"D.",
""
],
[
"Reichle",
"R.",
""
],
[
"Britton",
"J.",
""
],
[
"Blakestad",
"R. B.",
""
],
[
"Jost",
"J. D.",
""
],
[
"Langer",
"C.",
""
],
[
"Ozeri",
"R.",
""
],
[
"Seidelin",
"S.",
""
],
[
"Wineland",
"D. J.",
""
]
] |
0707.0964 | Alessio Marrani | A. Ceresole, S. Ferrara and A. Marrani | 4d/5d Correspondence for the Black Hole Potential and its Critical
Points | 1+24 pages; v2: references added, minor improvements; v3: further
minor improvements and clarifications | Class.Quant.Grav.24:5651-5666,2007 | 10.1088/0264-9381/24/22/023 | CERN-PH-TH/2007-112; UCLA/07/TEP/15 | hep-th | null | We express the d=4, N=2 black hole effective potential for cubic holomorphic
F functions and generic dyonic charges in terms of d=5 real special geometry
data. The 4d critical points are computed from the 5d ones, and their relation
is elucidated. For symmetric spaces, we identify the BPS and non-BPS classes of
attractors and the respective entropies. These are related by simple formulae,
interpolating between four and five dimensions, depending on the volume modulus
and on the 4d magnetic (or electric) charges, and holding true also for generic
field configurations and for non-symmetric cubic geometries.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:14:54 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 10:20:13 GMT"
},
{
"version": "v3",
"created": "Thu, 20 Sep 2007 16:39:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ceresole",
"A.",
""
],
[
"Ferrara",
"S.",
""
],
[
"Marrani",
"A.",
""
]
] |
0707.0965 | J\"org B\"unemann | Joerg Buenemann, David Rasch, Florian Gebhard | Hybridisation in two-band Hubbard models with different bandwidths | 11 pages, 12 figures, submitted to Journal of Physics: Condensed
Matter | J. Phys.: Condens. Matter 19, 436206 (2007) | 10.1088/0953-8984/19/43/436206 | null | cond-mat.str-el | null | We investigate the orbital selective Mott transition in two-band Hubbard
models by means of the Gutzwiller variational theory. In particular, we study
the influence of a finite local hybridisation between electrons in different
orbitals on the metal-insulator transition.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:36:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Buenemann",
"Joerg",
""
],
[
"Rasch",
"David",
""
],
[
"Gebhard",
"Florian",
""
]
] |
0707.0966 | Yasuo Watatani | Masatoshi Enomoto and Yasuo Watatani | Indecomposable representations of quivers on infinite-dimensional
Hilbert spaces | 34 pages | null | null | null | math.OA math.RT | null | We study indecomposable representations of quivers on separable
infinite-dimensional Hilbert spaces by bounded operators. We consider a
complement of Gabriel's theorem for these representations. Let $\Gamma$ be a
finite, connected quiver. If its underlying undirected graph contains one of
extended Dynkin diagrams $\tilde{A_n} (n \geq 0)$, $\tilde{D_n} (n \geq 4)$,
$\tilde{E_6}$,$\tilde{E_7}$ and $\tilde{E_8}$, then there exists an
indecomposable representation of $\Gamma$ on separable infinite-dimensional
Hilbert spaces.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:45:45 GMT"
},
{
"version": "v2",
"created": "Sat, 7 Jul 2007 06:34:43 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Enomoto",
"Masatoshi",
""
],
[
"Watatani",
"Yasuo",
""
]
] |
0707.0967 | Massimo De Luca | D. Lorenzetti (1), T. Giannini (1), V. M. Larionov (2, 3), E.
Kopatskaya (2), A. A. Arkharov (3), M. De Luca (1, 4), and A. Di Paola (1)
((1) INAF-Osservatorio Astronomico di Roma, (2) Sobolev Astronomical
Institute St. Petersburg State University, (3) Central Astronomical
Observatory of Pulkovo, (4) Universita' degli Studi di Roma ''Tor Vergata'') | An infrared view of the EXor variables: on the case of V1118 ORI | 23 pages. To be published to Astrophysical Journal | Astrophys.J.665:1182-1193,2007 | 10.1086/519764 | null | astro-ph | null | We investigate the relationship between the IR observed properties of the
EXor variables and the mechanisms active during their evolutionary stage. To
this aim, we have constructed a catalog of all the IR (1-100 micron)
photometric and spectroscopic observations appearing during the last 30 years
in the literature. New results of our monitoring program based on near- and
mid-IR photometry and near-IR spectroscopy and polarimetry of one object (V1118
Ori) are presented, complementing those given in a previous paper and related
to a different activity period. Our catalog indicates how the database
accumulated so far is inadequate for any statistical study of the EXor events.
Nevertheless, all the observational evidence can be interpreted into a coherent
scheme. The sources that present the largest brightness variations tend to
become bluer while brightening. The scenario of disk accretion based on viscous
friction between particles agrees with the observations. The new results on
V1118 Ori confirm such a general view. The striking novelty is represented by a
near-IR spectrum of V1118 Ori taken 1 yr after the last monitored outburst: any
emission line previously detected has now totally disappeared at our
sensitivity. For the same source, mid-IR photometry is provided here for the
first time and allows us to construct a meaningful SED. The first polarimetric
data show that V1118 Ori is intrinsically polarized and its spotted, magnetized
surface becomes recognizable during the less active phases.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:47:47 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Lorenzetti",
"D.",
""
],
[
"Giannini",
"T.",
""
],
[
"Larionov",
"V. M.",
""
],
[
"Kopatskaya",
"E.",
""
],
[
"Arkharov",
"A. A.",
""
],
[
"De Luca",
"M.",
""
],
[
"Di Paola",
"A.",
""
]
] |
0707.0968 | Tomasz Slupinski | T. Slupinski, J. Caban and K. Moskalik | Hole Transport in Impurity Band and Valence Bands Studied in Moderately
Doped GaAs:Mn Single Crystals | 9 pages, 2 figures, Proc. of 35th International School on the Physics
of Semiconducting Compounds, Jaszowiec 2007, Poland, to appear in Acta
Physica Polonica A (2007) | null | null | null | cond-mat.mtrl-sci | null | We report on simple experiment on temperature-dependent Hall effect
measurements in GaMnAs single crystalline samples with Mn composition estimated
at 0.05-0.3 at.% which is slightly below the onset of ferromagnetism. Impurity
band transport is visible for Mn compositions of ~0.3 at.% as a clear metallic
behaviour. The results show interesting situation that the Metal-Insulator
transition in GaAs:Mn occurs within the impurity band which is separated from
the valence bands for Mn concentrations studied here. We also discuss on the
equilibrium high temperature solubility limit of Mn in GaAs, unknown precisely
in the literature.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:48:10 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Slupinski",
"T.",
""
],
[
"Caban",
"J.",
""
],
[
"Moskalik",
"K.",
""
]
] |
0707.0969 | Yingbin Liang | Yingbin Liang, Venugopal V. Veeravalli, H. Vincent Poor | Resource Allocation for Wireless Fading Relay Channels: Max-Min Solution | To appear in the IEEE Transactions on Information Theory - Special
Issue on Models, Theory and Codes for Relaying and Cooperation in
Communication Networks, Vol. 53, No. 10, October 2007 | null | null | null | cs.IT math.IT | null | As a basic information-theoretic model for fading relay channels, the
parallel relay channel is first studied, for which lower and upper bounds on
the capacity are derived. For the parallel relay channel with degraded
subchannels, the capacity is established, and is further demonstrated via the
Gaussian case, for which the synchronized and asynchronized capacities are
obtained. The capacity achieving power allocation at the source and relay nodes
among the subchannels is characterized. The fading relay channel is then
studied, for which resource allocations that maximize the achievable rates are
obtained for both the full-duplex and half-duplex cases. Capacities are
established for fading relay channels that satisfy certain conditions.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:48:54 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Liang",
"Yingbin",
""
],
[
"Veeravalli",
"Venugopal V.",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0707.0970 | Miklos Abert | Miklos Abert and Gabor Elek | Non-abelian free groups admit non-essentially free actions on rooted
trees | null | null | null | null | math.GR math.CO | null | We show that every countable non-abelian free group $\Gamma $ admits a
spherically transitive action on a rooted tree $T$ such that the action of
$\Gamma $ on the boundary of $T$ is not essentially free. This reproves a
result of Bergeron and Gaboriau.
The existence of such an action answers a question of Grigorchuk,
Nekrashevich and Sushchanskii.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:53:24 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 22:28:27 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Abert",
"Miklos",
""
],
[
"Elek",
"Gabor",
""
]
] |
0707.0971 | Chunfang Li | Chunfang Li | Extension matrix representation theory of light beams and the Beauregard
effect | 10 pages, 1 figure, and changed contents | null | null | null | physics.optics | null | It is shown that a light beam in free space is representable by an integral
over a vectorial angular spectrum that is expressed in terms of an extension
matrix, which describes the vectorial nature of the beam. A symmetry axis of
the extension matrix is identified. When it is neither perpendicular nor
parallel to the propagation axis, we arrive at such beams that show us for the
first time the observable evidence of the Beauregard effect. The advanced
representation theory may yield any kinds of light beam, and the uncovered
Beauregard effect would play its unique roles in applications.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:56:01 GMT"
},
{
"version": "v2",
"created": "Fri, 11 Jan 2008 14:23:59 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Li",
"Chunfang",
""
]
] |
0707.0972 | Arti Chamoli | Arti Chamoli and C. M. Bhandari | Secure Direct Communication based on Ping-pong Protocol | 11 pages, 3 figures, 1 table | null | null | null | quant-ph | null | Communication security with quantum key distribution has been one of the
important features of quantum information theory. A novel concept of secured
direct communication has been the next step forward without the need to
establish any shared secret key. The present paper is based on the ping-pong
protocol with three particle GHZ state as the initial state where the receiver
can simultaneously receive information from two parties. Possible eavesdropping
on the travelling particle has been examined.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:56:15 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Chamoli",
"Arti",
""
],
[
"Bhandari",
"C. M.",
""
]
] |
0707.0973 | Cathie Clarke | C. J.Clarke | The formation of extreme mass ratio binary stars: a tribute to Eduardo
De lgado Donate | To appear in Pathways through an eclectic Universe, J. H. Knapen, T.
J. Mahoney, and A. Vazdekis (Eds.), ASP Conf. Ser., 2007 | null | null | null | astro-ph | null | Eduardo Delgado was due to have presented a poster at this meeting on his
latest results on the formation of extreme mass ratio binaries. Tragically,
Eduardo was among those killed in a hiking accident in Tenerife earlier this
year. As his PhD supervisor, and as a longstanding collaborator, the organisers
of this meeting kindly invited me to incorporate a report on his most recent
work into a more general tribute to his life and work.
I will reflect on Eduardo's scientific career, the problems that motivated
him and his achievements, focusing particularly on a problem which had
intrigued us both for several years and on which Eduardo was making important
progress at the time of his death. Finally, I will mention the personal
qualities that Eduardo brought to his work and the acute sense of loss that is
shared by all those - friends and collaborators - who were privileged to know
him.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 13:59:32 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Clarke",
"C. J.",
""
]
] |
0707.0974 | Philippe Droz-Vincent | Philippe Droz-Vincent | Scalar products of elementary distributions | 27 pages | null | 10.1063/1.2931449 | null | math-ph math.MP | null | The field of real numbers being extended as a larger commutative field, we
investigate the possibility of defining a scalar product for the distributions
of finite discrete support. Then we focus on the most simple possible extension
(which is an ordered field), we provide explicit formulas for this scalar
product, and we exhibit a structure of positive definite inner-product space.
In a one-dimensional application to the Schroedinger equation, the
distributions supported by the origin are embedded into a bra-ket vector space,
where the "singular" potential describing point interaction is defined in a
natural way. A contact with the hyperreal numbers that arise in nonstandard
analysis is possible but not essential, our extensions of $\bf R$ and $\bf C$
being obtained by a quite elementary method.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:02:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Droz-Vincent",
"Philippe",
""
]
] |
0707.0975 | Imre B\'alint | Imre Balint | Scalar extension of bicoalgebroids | 24 pages, to appear in Applied Categorical Structures, special issue
'Algebras and Coalgebras' | null | null | null | math.QA math.CT | null | After recalling the definition of a bicoalgebroid, we define comodules and
modules over a bicoalgebroid. We construct the monoidal category of comodules,
and define Yetter--Drinfel'd modules over a bicoalgebroid. It is proved that
the Yetter--Drinfel'd category is monoidal and pre--braided just as in the case
of bialgebroids, and is embedded into the one--sided center of the comodule
category. We proceed to define Braided Cocommutative Coalgebras (BCC) over a
bicoalgebroid, and dualize the scalar extension construction of Brzezinski and
Militaru [2] and Balint and Slachanyi [1], originally applied to bialgebras and
bialgebroids, to bicoalgebroids. A few classical examples of this construction
are given. Identifying the comodule category over a bicoalgebroid with the
category of coalgebras of the associated comonad, we obtain a comonadic
(weakened) version of Schauenburg's theorem. Finally, we take a look at the
scalar extension and braided cocommutative coalgebras from a (co--)monadic
point of view.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:09:23 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Balint",
"Imre",
""
]
] |
0707.0976 | Daniela Visetti | Daniela Visetti | Multiplicity of solutions of a zero mass nonlinear equation on a
Riemannian manifold | null | null | null | null | math.AP | null | The relation between the number of solutions of a nonlinear equation on a
Riemannian manifold and the topology of the manifold itself is studied. The
technique is based on Ljusternik-Schnirelmann category and Morse theory.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:13:46 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Visetti",
"Daniela",
""
]
] |
0707.0977 | Baowen Li | Nuo Yang, Nianbei Li, Lei Wang, and Baowen Li | Thermal rectification and negative differential thermal resistance in
lattices with mass gradient | 4 pages 5 eps figs. Accepted for pub. in Phys. Rev. B Rap. Comm | null | 10.1103/PhysRevB.76.020301 | null | cond-mat.dis-nn cond-mat.mtrl-sci | null | We study thermal properties of one dimensional(1D) harmonic and anharmonic
lattices with mass gradient. It is found that the temperature gradient can be
built up in the 1D harmonic lattice with mass gradient due to the existence of
gradons. The heat flow is asymmetric in the anharmonic lattices with mass
gradient. Moreover, in a certain temperature region the {\it negative
differential thermal resistance} is observed. Possible applications in
constructing thermal rectifier and thermal transistor by using the graded
material are discussed.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:16:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yang",
"Nuo",
""
],
[
"Li",
"Nianbei",
""
],
[
"Wang",
"Lei",
""
],
[
"Li",
"Baowen",
""
]
] |
0707.0978 | Nadia Fawaz | Nadia Fawaz (1), David Gesbert (1), Merouane Debbah (2) ((1) Eurecom
Institute, (2) Supelec) | When Network Coding and Dirty Paper Coding meet in a Cooperative Ad Hoc
Network | 7 pages, 7 figures | null | null | null | cs.IT math.IT | null | We develop and analyze new cooperative strategies for ad hoc networks that
are more spectrally efficient than classical DF cooperative protocols. Using
analog network coding, our strategies preserve the practical half-duplex
assumption but relax the orthogonality constraint. The introduction of
interference due to non-orthogonality is mitigated thanks to precoding, in
particular Dirty Paper coding. Combined with smart power allocation, our
cooperation strategies allow to save time and lead to more efficient use of
bandwidth and to improved network throughput with respect to classical RDF/PDF.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 19:56:44 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Fawaz",
"Nadia",
""
],
[
"Gesbert",
"David",
""
],
[
"Debbah",
"Merouane",
""
]
] |
0707.0979 | Ken Pounds | K.A.Pounds and B.J.Wilkes | Comparison of high and low state X-ray spectra in the Type 1 QSO 2MASS
0918+2117 | accepted for publication in Monthly Notices of the RAS | null | 10.1111/j.1365-2966.2007.12205.x | null | astro-ph | null | When observed by XMM-Newton in 2003 the type 1 QSO 2MASS 0918+2117 was found
to in a low flux state, some ~4-5 times fainter than during an earlier Chandra
observation. The 2-6 keV spectrum was unusually hard, with evidence for a
reflection-dominated continuum, while a soft excess prevented confirmation of
the anticipated low energy absorber. In a second XMM-Newton observation in
2005, the X-ray flux is found to have recovered, with a 2-10 keV continuum
slope now typical of broad-line active galaxy, and clear evidence for low
energy absorption. We find the preferred ionisation state of the absorbing gas
to be low, consistent with the red nucleus and strong optical polarisation of
2MASS 0918+2117. A residual soft excess is of similar spectral form and flux to
that seen in 2003.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:32:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pounds",
"K. A.",
""
],
[
"Wilkes",
"B. J.",
""
]
] |
0707.0980 | Marek Wolf | Marek Wolf | Analog of the Skewes number for twin primes | Changes: New Figure 1 and a few sentences of justification in favor
of the conjecture (5) are made | null | null | null | math.NT | null | The results of the computer investigation of the sign changes of the
difference between the number of twin primes $\pi_2(x)$ and the
Hardy--Littlewood conjecture $c_2\Li_2(x)$ are reported. It turns out that
$\pi_2(x) - c_2\Li_2(x)$ changes the sign at unexpectedly low values of $x$ and
for $x<2^{42}$ there are over 90000 sign changes of this difference. It is
conjectured that the number of sign changes of $\pi_2(x) - c_2\Li_2(x)$ for
$x\in (1, T)$ is given by $\sqrt T/\log(T)$.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:49:34 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jan 2008 09:22:01 GMT"
}
] | 2008-01-15T00:00:00 | [
[
"Wolf",
"Marek",
""
]
] |
0707.0981 | Domhnall Murphy | D.S. Murphy, J.F. McCann, J. Goold, Th. Busch | Boson Pairs in a One-dimensional Split Trap | 9 pages, 8 figures | null | 10.1103/PhysRevA.76.053616 | null | quant-ph | null | We describe the properties of a pair of ultracold bosonic atoms in a
one-dimensional harmonic trapping potential with a tunable zero-ranged barrier
at the trap centre. The full characterisation of the ground state is done by
calculating the reduced single-particle density, the momentum distribution and
the two-particle entanglement. We derive several analytical expressions in the
limit of infinite repulsion (Tonks-Girardeau limit) and extend the treatment to
finite interparticle interactions by numerical solution. As pair interactions
in double wells form a fundamental building block for many-body systems in
periodic potentials, our results have implications for a wide range of
problems.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:38:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Murphy",
"D. S.",
""
],
[
"McCann",
"J. F.",
""
],
[
"Goold",
"J.",
""
],
[
"Busch",
"Th.",
""
]
] |
0707.0982 | Paul Kinsler | P. Kinsler | Pulse propagation methods in nonlinear optics | 14 pages | null | null | null | physics.optics | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I present an overview of pulse propagation methods used in nonlinear optics,
covering both full-field and envelope-and-carrier methods. Both wideband and
narrowband cases are discussed. Three basic forms are considered -- those based
on (a) Maxwell's equations, (b) directional fields, and (c) the second order
wave equation. While Maxwell's equations simulators are the most general,
directional field methods can give significant computational and conceptual
advantages. Factorizations of the second order wave equation complete the set
by being the simplest to understand. One important conclusion is that that
envelope methods based on forward-only directional field propagation has made
the traditional envelope methods (such as the SVEA, and extensions) based on
the second order wave equation utterly redundant.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 19:12:38 GMT"
},
{
"version": "v2",
"created": "Fri, 10 Aug 2007 16:13:51 GMT"
},
{
"version": "v3",
"created": "Tue, 10 Jun 2008 08:40:04 GMT"
},
{
"version": "v4",
"created": "Tue, 12 Aug 2008 14:08:02 GMT"
},
{
"version": "v5",
"created": "Mon, 20 Dec 2010 19:01:27 GMT"
}
] | 2010-12-21T00:00:00 | [
[
"Kinsler",
"P.",
""
]
] |
0707.0983 | Peter Newstead | S. B. Bradlow, O. Garcia-Prada, V. Mercat, V. Munoz and P. E. Newstead | Moduli spaces of coherent systems of small slope on algebraic curves | 27 pages; minor presentational changes and typographical corrections | null | null | null | math.AG | null | Let $C$ be an algebraic curve of genus $g\ge2$. A coherent system on $C$
consists of a pair $(E,V)$, where $E$ is an algebraic vector bundle over $C$ of
rank $n$ and degree $d$ and $V$ is a subspace of dimension $k$ of the space of
sections of $E$. The stability of the coherent system depends on a parameter
$\alpha$. We study the geometry of the moduli space of coherent systems for
$0<d\le2n$. We show that these spaces are irreducible whenever they are
non-empty and obtain necessary and sufficient conditions for non-emptiness.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:41:46 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Dec 2007 13:55:56 GMT"
}
] | 2007-12-10T00:00:00 | [
[
"Bradlow",
"S. B.",
""
],
[
"Garcia-Prada",
"O.",
""
],
[
"Mercat",
"V.",
""
],
[
"Munoz",
"V.",
""
],
[
"Newstead",
"P. E.",
""
]
] |
0707.0984 | Branko Dragovich | Branko Dragovich, Dusan Mihajlovic | p-Adic and Adelic Rational Dynamical Systems | 12 pages. Talk at the 4th Summer School in Modern Mathematical
Physics, September 2006, Belgrade (Serbia) | SFIN XX A1 (2007) 187 - 196 | null | null | math-ph math.DS math.MP nlin.CD | null | In the framework of adelic approach we consider real and p-adic properties of
dynamical system given by linear fractional map f (x) = (a x + b)/(c x + d),
where a, b, c and d are rational numbers. In particular, we investigate
behavior of this adelic dynamical system when fixed points are rational. It is
shown that any of rational fixed points is p-adic indifferent for all but a
finite set of primes. Only for finite number of p-adic cases a rational fixed
point may be attractive or repelling. The present analysis is a continuation of
the paper math-ph/0612058. Some possible generalizations are discussed.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:49:33 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Dragovich",
"Branko",
""
],
[
"Mihajlovic",
"Dusan",
""
]
] |
0707.0985 | Mike Gunn | J.R. Holt and J.M.F. Gunn | Rotating molecules in optical lattices, alignment and monopole crystals | 4 pages, 1 figure | null | null | null | cond-mat.other | null | The recent progress towards production of near-ground state
quantum-degenerate molecules raises the issue of how such "small" molecules
behave in an optical lattice. In this Letter we show that the coupling of the
molecular orientation to the local electric field direction will provide
severalnew phenomena. In the case where the lasers forming different
crystallographic directions of the lattice are incoherent, the orientation of
the molecules is conserved (for L = 1) and a novel form of anisotropic
superfluidity can be expected. When the lasers are coherent, and the optical
lattice is such that the splitting of the rotational levels is large compared
to the centre of mass energies,an adiabaic description of the molecular
orientation is appropriate. This leads to geometric vector potentials,
pseudo-magnetic monopoles and a frustrated band structure with degenerate
minima.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 14:53:40 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Holt",
"J. R.",
""
],
[
"Gunn",
"J. M. F.",
""
]
] |
0707.0986 | Paul Kinsler | P. Kinsler | Limits of the uni-directional pulse propagation approximation | 6 pages, 6 figures; this version contains an additional appendix not
present in the published version | J. Opt. Soc. Am. B 24, 2363-2368 (2007) | 10.1364/JOSAB.24.002363 | null | physics.optics | null | I apply the method of characteristics to both bi-directional and
uni-directional pulse propagation in dispersionless media containing
nonlinearity of arbitrary order. The differing analytic predictions for the
shocking distance quantify the effects of the uni-directional approximation
used in many pulse propagation models. Results from numerical simulations
support the theoretical predictions, and reveal the nature of the coupling
between forward and backward waves.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:14:22 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Aug 2007 09:50:17 GMT"
}
] | 2008-07-24T00:00:00 | [
[
"Kinsler",
"P.",
""
]
] |
0707.0987 | Francois Demontoux | Fran\c{c}ois Demontoux (IMS), B\'en\'edicte Le Crom (IMS), Gilles
Ruffi\'e (IMS), Jean Pierre Wigneron (EPHYSE - UR1263), Jennifer Grant,
Daniel Medina Hernandez (IMS) | Inversion model validation of ground emissivity. Contribution to the
development of SMOS algorithm | null | Inversion model validation of ground emissivity. Contribution to
the development of SMOS algorithm (2007) 4 | null | null | physics.geo-ph | null | SMOS (Soil Moisture and Ocean Salinity), is the second mission of 'Earth
Explorer' to be developed within the program 'Living Planet' of the European
Space Agency (ESA). This satellite, containing the very first 1.4GHz
interferometric radiometer 2D, will carry out the first cartography on a
planetary scale of the moisture of the grounds and the salinity of the oceans.
The forests are relatively opaque, and the knowledge of moisture remains
problematic. The effect of the vegetation can be corrected thanks a simple
radiative model. Nevertheless simulations show that the effect of the litter on
the emissivity of a system litter + ground is not negligible. Our objective is
to highlight the effects of this layer on the total multi layer system. This
will make it possible to lead to a simple analytical formulation of a model of
litter which can be integrated into the calculation algorithm of SMOS.
Radiometer measurements, coupled to dielectric characterizations of samples in
laboratory can enable us to characterize the geological structure. The goal of
this article is to present the step which we chose to validate this analytical
model.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:04:31 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Demontoux",
"François",
"",
"IMS"
],
[
"Crom",
"Bénédicte Le",
"",
"IMS"
],
[
"Ruffié",
"Gilles",
"",
"IMS"
],
[
"Wigneron",
"Jean Pierre",
"",
"EPHYSE - UR1263"
],
[
"Grant",
"Jennifer",
"",
"IMS"
],
[
"Hernandez",
"Daniel Medina",
"",
"IMS"
]
] |
0707.0988 | Sascha Turczyk | B. M. Dassinger, Th. Feldmann, Th. Mannel, S. Turczyk | Model-independent Analysis of Lepton Flavour Violating Tau Decays | 14 pages, 10 figures, references and comments added | JHEP 0710:039,2007 | 10.1088/1126-6708/2007/10/039 | SI-HEP-2007-06 | hep-ph | null | Many models for physics beyond the Standard Model predict lepton-flavour
violating decays of charged leptons at a level which may become observable very
soon. In the present paper we investigate the decays of a Tau into three
charged leptons in a generic way, based on effective-field-theory methods,
where the relevant operators are classified according to their chirality
structure. We work out the decay distributions and discuss phenomenological
implications.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:06:39 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Jul 2007 11:33:39 GMT"
},
{
"version": "v3",
"created": "Wed, 10 Oct 2007 13:45:19 GMT"
}
] | 2010-02-03T00:00:00 | [
[
"Dassinger",
"B. M.",
""
],
[
"Feldmann",
"Th.",
""
],
[
"Mannel",
"Th.",
""
],
[
"Turczyk",
"S.",
""
]
] |
0707.0989 | Svante Janson | Svante Janson, Niclas Petersson | The integral of the supremum process of Brownian motion | 9 pages, 1 figure | null | null | null | math.PR | null | In this paper we study the integral of the supremum process of standard
Brownian motion. We present an explicit formula for the moments of the integral
(or area) A(T), covered by the process in the time interval [0,T]. The Laplace
transform of A(T) follows as a consequence. The main proof involves a double
Laplace transform of A(T) and is based on excursion theory and local time for
Brownian motion.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:06:58 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Janson",
"Svante",
""
],
[
"Petersson",
"Niclas",
""
]
] |
0707.0990 | Ivan Dmitriev | I.A. Dmitriev, A.D. Mirlin, and D.G. Polyakov | Theory of the fractional microwave-induced resistance oscillations | 4 pages, 2 figures; V2: published version (typos corrected,
references added and updated) | Phys. Rev. Lett. 99, 206805 (2007) | 10.1103/PhysRevLett.99.206805 | null | cond-mat.mes-hall cond-mat.dis-nn | null | We develop a systematic theory of microwave-induced oscillations in
magnetoresistivity of a 2D electron gas in the vicinity of fractional harmonics
of the cyclotron resonance, observed in recent experiments. We show that in the
limit of well-separated Landau levels the effect is dominated by a change of
the distribution function induced by multiphoton processes. At moderate
magnetic field, a single-photon mechanism originating from the
microwave-induced sidebands in the density of states of disorder-broadened
Landau levels becomes important.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:12:24 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Nov 2007 12:42:42 GMT"
}
] | 2007-11-27T00:00:00 | [
[
"Dmitriev",
"I. A.",
""
],
[
"Mirlin",
"A. D.",
""
],
[
"Polyakov",
"D. G.",
""
]
] |
0707.0991 | Svante Janson | Svante Janson, Guy Louchard | Tail estimates for the Brownian excursion area and other Brownian areas | 34 pages | null | null | null | math.PR | null | Several Brownian areas are considered in this paper: the Brownian excursion
area, the Brownian bridge area, the Brownian motion area, the Brownian meander
area, the Brownian double meander area, the positive part of Brownian bridge
area, the positive part of Brownian motion area. We are interested in the
asymptotics of the right tail of their density function. Inverting a double
Laplace transform, we can derive, in a mechanical way, all terms of an
asymptotic expansion. We illustrate our technique with the computation of the
first four terms. We also obtain asymptotics for the right tail of the
distribution function and for the moments. Our main tool is the two-dimensional
saddle point method.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:14:16 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Janson",
"Svante",
""
],
[
"Louchard",
"Guy",
""
]
] |
0707.0992 | Massimiliano (Max) Bonamente | M. Bonamente, J. Nevalainen, R. Lieu | Soft and hard X-ray excess emission in Abell 3112 observed with Chandra | Ap.J. in press, emulateapj style | null | 10.1086/521381 | null | astro-ph | null | Chandra ACIS-S observations of the galaxy cluster A3112 feature the presence
of an excess of X-ray emission above the contribution from the diffuse hot gas,
which can be equally well modeled with an additional non-thermal power-law
model or with a low-temperature thermal model of low metal abundance. We show
that the excess emission cannot be due to uncertainties in the background
subtraction or in the Galactic HI column density. Calibration uncertainties in
the ACIS detector that may affect our results are addressed by comparing the
Chandra data to XMM MOS and PN spectra. While differences between the three
instruments remain, all detect the excess in similar amounts, providing
evidence against an instrumental nature of the excess. Given the presence of
non-thermal radio emission near the center of A3112, we argue that the excess
X-ray emission is of non-thermal nature and distributed throughout the entire
X-ray bandpass, from soft to hard X-rays. The excess can be explained with the
presence of a population of relativistic electrons with ~7% of the cluster's
gas pressure. We also discuss a possible thermal nature of the excess, and
examine the problems associated with such interpretation.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:18:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bonamente",
"M.",
""
],
[
"Nevalainen",
"J.",
""
],
[
"Lieu",
"R.",
""
]
] |
0707.0993 | Bernd Kaestner | B. Kaestner, V. Kashcheyevs, S. Amakawa, L. Li, M. D. Blumenthal, T.
J. B. M. Janssen, G. Hein, K. Pierz, T. Weimann, U. Siegner, H. W. Schumacher | Single-parameter non-adiabatic quantized charge pumping | 4 pages, 4 figures | Physical Review B 77, 153301 (2008) | 10.1103/PhysRevB.77.153301 | null | cond-mat.mes-hall | null | Controlled charge pumping in an AlGaAs/GaAs gated nanowire by
single-parameter modulation is studied experimentally and theoretically.
Transfer of integral multiples of the elementary charge per modulation cycle is
clearly demonstrated. A simple theoretical model shows that such a quantized
current can be generated via loading and unloading of a dynamic quasi-bound
state. It demonstrates that non-adiabatic blockade of unwanted tunnel events
can obliterate the requirement of having at least two phase-shifted periodic
signals to realize quantized pumping. The simple configuration without multiple
pumping signals might find wide application in metrological experiments and
quantum electronics.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:20:43 GMT"
}
] | 2008-04-15T00:00:00 | [
[
"Kaestner",
"B.",
""
],
[
"Kashcheyevs",
"V.",
""
],
[
"Amakawa",
"S.",
""
],
[
"Li",
"L.",
""
],
[
"Blumenthal",
"M. D.",
""
],
[
"Janssen",
"T. J. B. M.",
""
],
[
"Hein",
"G.",
""
],
[
"Pierz",
"K.",
""
],
[
"Weimann",
"T.",
""
],
[
"Siegner",
"U.",
""
],
[
"Schumacher",
"H. W.",
""
]
] |
0707.0994 | Hans Vernaeve | M. Oberguggenberger and H. Vernaeve | Internal sets and internal functions in Colombeau theory | null | J. Math. Anal. Appl. (2008) 341: 649-659 | 10.1016/j.jmaa.2007.10.030 | null | math.FA | null | Inspired by nonstandard analysis, we define and study internal subsets and
internal functions in algebras of Colombeau generalized functions. We prove a
saturation principle for internal sets and provide applications to Colombeau
algebras.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:22:43 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Oberguggenberger",
"M.",
""
],
[
"Vernaeve",
"H.",
""
]
] |
0707.0995 | Remon Cornelisse | R. Cornelisse, R. Wijnands, J. Homan | An XMM-Newton observation of the neutron star X-ray transient 2S
1803-245 in quiescence | 5 pages, 3 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12207.x | null | astro-ph | null | We observed the neutron star X-ray transient 2S 1803-245 in quiescence with
the X-ray satellite XMM-Newton, but did not detect it. An analysis of the X-ray
bursts observed during the 1998 outburst of 2S 1803-245 gives an upper-limit to
the distance of <7.3 kpc, leading to an upper-limit on the quiescent 0.5-10 keV
X-ray luminosity of <2.8x10^32 erg/s (3sigma). Since the expected orbital
period of 2S 1803-245 is several hrs, this limit is not much higher than those
observed for the quiescent black hole transients with similar orbital periods.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:23:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cornelisse",
"R.",
""
],
[
"Wijnands",
"R.",
""
],
[
"Homan",
"J.",
""
]
] |
0707.0996 | Chethil Sudheesh | C. Sudheesh | Non-classical effects in wave packet dynamics | PhD Thesis, IIT Madras, December 2005 | null | null | null | quant-ph | null | Treating the ideal coherent state as a reference state, the effects due to
departure from coherence of an initial wave packet propagating through a
nonlinear medium, were examined, specifically in the context of non-classical
effects such as revivals, fractional revivals, squeezing and higher-order
squeezing during its temporal evolution. Further, these studies were extended
to examine the role of quantum entanglement in bipartite systems. The dynamics
of quantum expectation values were tracked carefully in various cases and the
conditions under which a wave packet spreads chaotically, were investigated.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:51:00 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Sudheesh",
"C.",
""
]
] |
0707.0997 | Oleksiy Khorunzhiy | O. Khorunzhiy | On Connected Diagrams and Cumulants of Erdos-Renyi Matrix Models | 34 pages, 8 figures | null | 10.1007/s00220-008-0533-2 | null | math-ph math.MP math.PR | null | Regarding the adjacency matrices of n-vertex graphs and related graph
Laplacian, we introduce two families of discrete matrix models constructed both
with the help of the Erdos-Renyi ensemble of random graphs. Corresponding
matrix sums represent the characteristic functions of the average number of
walks and closed walks over the random graph. These sums can be considered as
discrete analogs of the matrix integrals of random matrix theory.
We study the diagram structure of the cumulant expansions of logarithms of
these matrix sums and analyze the limiting expressions in the cases of constant
and vanishing edge probabilities as n tends to infinity.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:18:06 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 15:28:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Khorunzhiy",
"O.",
""
]
] |
0707.0998 | Rupert Frank | Rupert L. Frank, Barry Simon, Timo Weidl | Eigenvalue Bounds for Perturbations of Schrodinger Operators and Jacobi
Matrices With Regular Ground States | 11 pages | null | 10.1007/s00220-008-0453-1 | null | math.SP math-ph math.MP | null | We prove general comparison theorems for eigenvalues of perturbed Schrodinger
operators that allow proof of Lieb--Thirring bounds for suitable non-free
Schrodinger operators and Jacobi matrices.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:41:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Frank",
"Rupert L.",
""
],
[
"Simon",
"Barry",
""
],
[
"Weidl",
"Timo",
""
]
] |
0707.0999 | Roberto Decarli | R. Decarli, G. Gavazzi, I. Arosio, L. Cortese, A. Boselli, C.
Bonfanti, M. Colpi | The census of nuclear activity of late-type galaxies in the Virgo
cluster | The paper contains 13 figures and 5 tables; accepted for publication
in MNRAS | null | 10.1111/j.1365-2966.2007.12208.x | null | astro-ph | null | The first spectroscopic census of AGNs associated to late-type galaxies in
the Virgo cluster is carried on by observing 213 out of a complete set of 237
galaxies more massive than M_dyn>10^{8.5} solar masses. Among them, 77 are
classified as AGNs (including 21 transition objects, 47 LINERs and 9 Seyferts),
and comprize 32% of the late-type galaxies in Virgo. Due to spectroscopic
incompleteness at most 21 AGNs are missed in the survey, so that the fraction
would increase up to 41%. Using corollary Near-IR observations, that enable us
to estimate galaxies dynamical masses, it is found that AGNs are hosted
exclusively in massive galaxies, i.e. M_dyn\gsim 10^{10} solar masses. Their
frequency increases steeply with the dynamical mass from zero at
M_dyn\approx10^{9.5} solar masses to virtually 1 at M_dyn>10^{11.5} solar
masses. These frequencies are consistent with the ones of low luminosity AGNs
found in the general field by the SDSS. Massive galaxies that harbor AGNs
commonly show conspicuous r-band star-like nuclear enhancements. Conversely
they often, but not necessarily contain massive bulges. Few well known AGNs
(e.g. M61, M100, NGC4535) are found in massive Sc galaxies with little or no
bulge. The AGN fraction seems to be only marginally sensitive to galaxy
environment. We infer the black hole masses using the known scaling relations
of quiescent black holes. No black holes lighter than $\sim 10^6$ \msol are
found active in our sample.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:42:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Decarli",
"R.",
""
],
[
"Gavazzi",
"G.",
""
],
[
"Arosio",
"I.",
""
],
[
"Cortese",
"L.",
""
],
[
"Boselli",
"A.",
""
],
[
"Bonfanti",
"C.",
""
],
[
"Colpi",
"M.",
""
]
] |
0707.1000 | F. J. Castro-Jimenez | F.J. Castro-Jimenez (1), J. Gago (1), M.I. Hartillo-Hermoso (2) and
J.M. Ucha (1)((1) University of Seville, (2) University of Cadiz) | A vanishing theorem for a class of logarithmic D-modules | 13 pages. To appear in Revista Matem\'atica Iberoamericana | null | null | null | math.AG | null | Let $O_X$ (resp. $D_X$) be the sheaf of holomorphic functions (resp. the
sheaf of linear differential operators with holomorphic coefficients) on $X$
(=the complex affine n-space). Let $Y$ be a locally weakly quasi-homogeneous
free divisor defined by a polynomial $f$. In this paper we prove that, locally,
the annihilating ideal of $1/f^k$ over $D_X$ is generated by linear
differential operators of order 1 (for $k$ big enough). For this purpose we
prove a vanishing theorem for the extension groups of a certain logarithmic
$D_X$--module with $O_X$. The logarithmic $D_X$--module is naturally associated
with $Y$. This result is related to the so called Logarithmic Comparison
Theorem.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:45:25 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Castro-Jimenez",
"F. J.",
"",
"University of Seville"
],
[
"Gago",
"J.",
"",
"University of Seville"
],
[
"Hartillo-Hermoso",
"M. I.",
"",
"University of Cadiz"
],
[
"Ucha",
"J. M.",
"",
"University of Seville"
]
] |
0707.1001 | Oriol Vendrell | Oriol Vendrell, Fabien Gatti, David Lauvergnat, Hans-Dieter Meyer | Full dimensional (15D) quantum-dynamical simulation of the protonated
water-dimer I: Hamiltonian setup and analysis of the ground vibrational state | 46 pages, 5 figures, submitted to J. Chem. Phys | J. Chem. Phys., 2007, 127, 184302-1 -- 184302-17 | 10.1063/1.2787588 | null | physics.chem-ph | null | Quantum-dynamical full-dimensional (15D) calculations are reported for the
protonated water dimer (H5O2+) using the multiconfiguration time-dependent
Hartree (MCTDH) method. The dynamics is described by curvilinear coordinates.
The expression of the kinetic energy operator in this set of coordinates is
given and its derivation, following the polyspherical method, is discussed. The
PES employed is that of Huang et al. [JCP, 122, 044308, (2005)]. A scheme for
the representation of the potential energy surface (PES) is discussed which is
based on a high dimensional model representation scheme (cut-HDMR), but
modified to take advantage of the mode-combination representation of the
vibrational wavefunction used in MCTDH. The convergence of the PES expansion
used is quantified and evidence is provided that it correctly reproduces the
reference PES at least for the range of energies of interest. The reported zero
point energy of the system is converged with respect to the MCTDH expansion and
in excellent agreement (16.7 cm-1 below) with the diffusion Monte Carlo result
on the PES of Huang et al. The highly fluxional nature of the cation is
accounted for through use of curvilinear coordinates. The system is found to
interconvert between equivalent minima through wagging and internal rotation
motions already when in the ground vibrational-state, i.e., T=0. It is shown
that a converged quantum-dynamical description of such a flexible, multi-minima
system is possible.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:54:38 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Vendrell",
"Oriol",
""
],
[
"Gatti",
"Fabien",
""
],
[
"Lauvergnat",
"David",
""
],
[
"Meyer",
"Hans-Dieter",
""
]
] |
0707.1002 | Andrea Alu | Alessandro Salandrino, Andrea Alu, Nader Engheta | Parallel, Series, and Intermediate Interconnections of Optical
Nanocircuit Elements Part 1: Analytical Solution | 21 pages, 5 figures | null | 10.1364/JOSAB.24.003007 | null | cond-mat.mtrl-sci | null | Following our recent development of the paradigm for extending the classic
concepts of circuit elements to the infrared and optical frequencies [N.
Engheta, A. Salandrino, A. Alu, Phys. Rev. Lett. 95, 095504 (2005)], in this
paper we investigate the possibility of connecting nanoparticles in series and
in parallel configurations, acting as nanocircuit elements, In particular, we
analyze a pair of conjoined half-cylinders, whose relatively simple geometry
may be studied and analyzed analytically. In this first part of the work, we
derive a closed-form quasi-static analytical solution of the boundary-value
problem associated with this geometry, which will be applied in Part II for a
nanocircuit and physical interpretation of these results.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 15:56:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Salandrino",
"Alessandro",
""
],
[
"Alu",
"Andrea",
""
],
[
"Engheta",
"Nader",
""
]
] |
0707.1003 | Andrea Alu | Andrea Alu, Alessandro Salandrino, Nader Engheta | Parallel, Series, and Intermediate Interconnections of Optical
Nanocircuit Elements Part 2: Nanocircuit and Physical Interpretation | 27 pages, 7 figures | null | 10.1364/JOSAB.24.003014 | null | cond-mat.mtrl-sci | null | Applying the analytical closed-form solutions of the 'quasi-static' potential
distribution around two conjoined resonant half-cylinders with different
permittivities, reported in the first part of our manuscript, here we interpret
these results in terms of our nanocircuit paradigm applicable to nanoparticles
at infrared and optical frequencies [N. Engheta, A. Salandrino, A. Alu, Phys.
Rev. Lett. 95, 095504 (2005)]. We investigate the possibility of connecting in
series and parallel configurations plasmonic and/or dielectric nanoparticles
acting as nanocircuit elements, with a goal for the design of a more complex
nanocircuit circuit system with the desired response. The present analysis
fully validates the heuristic predictions regarding the parallel and series
combination of a pair of nanocircuit elements. Moreover, the geometries under
analysis present interesting peculiar features in their wave interaction, such
as the intermediate stage between the parallel and series configurations, which
may be of interest for certain applications. In particular, the resonant
nanocircuit configuration analyzed here may dramatically change, in a
continuous way, its effective total impedance by simply rotating its
orientation with respect to the polarization of the impressed optical electric
field, providing a novel optical nanodevice that may alter its function by
rotation with respect to the impressed optical local field.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:00:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Alu",
"Andrea",
""
],
[
"Salandrino",
"Alessandro",
""
],
[
"Engheta",
"Nader",
""
]
] |
0707.1004 | Oriol Vendrell | Oriol Vendrell, Fabien Gatti, Hans-Dieter Meyer | Full dimensional (15D) quantum-dynamical simulation of the protonated
water-dimer II: infrared spectrum and vibrational dynamics | 30 pages, 6 figures, submitted to J. Chem. Phys | J. Chem. Phys., 2007, 127, 184303-1 -- 184303-10 | 10.1063/1.2787596 | null | physics.chem-ph | null | The infrared absorption spectrum of the protonated water dimer (H5O2+) is
simulated in full dimensionality (15D) in the spectral range 0-4000 cm-1. The
calculations are performed using the Multiconfiguration Time-Dependent Hartree
(MCTDH) method for propagation of wavepackets. All the fundamentals and several
overtones of the vibrational motion are computed. The spectrum of H5O2+ is
shaped to a large extent by couplings of the proton-transfer motion to large
amplitude fluxional motions of the water molecules, water bending and
water-water stretch motions. These couplings are identified and discussed, and
the corresponding spectral lines assigned. The large couplings featured by
H5O2+ do not hinder, however, to describe the coupled vibrational motion by
well defined simple types of vibration (stretching, bending, etc.) based on
well defined modes of vibration, in terms of which the spectral lines are
assigned. Comparison of our results to recent experiments and calculations on
the system is given. The reported MCTDH IR-spectrum is in very good agreement
to the recently measured spectrum by Hammer et al. [JCP, 122, 244301, (2005)].
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:03:28 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Vendrell",
"Oriol",
""
],
[
"Gatti",
"Fabien",
""
],
[
"Meyer",
"Hans-Dieter",
""
]
] |
0707.1005 | Jovanka Lukic | Frauke Liers, Jovanka Lukic, Enzo Marinari, Andrea Pelissetto, Ettore
Vicari | Zero-temperature behavior of the random-anisotropy model in the
strong-anisotropy limit | null | null | 10.1103/PhysRevB.76.174423 | null | cond-mat.dis-nn | null | We consider the random-anisotropy model on the square and on the cubic
lattice in the strong-anisotropy limit. We compute exact ground-state
configurations, and we use them to determine the stiffness exponent at zero
temperature; we find $\theta = -0.275(5)$ and $\theta \approx 0.2$ respectively
in two and three dimensions. These results show that the low-temperature phase
of the model is the same as that of the usual Ising spin-glass model. We also
show that no magnetic order occurs in two dimensions, since the expectation
value of the magnetization is zero and spatial correlation functions decay
exponentially. In three dimensions our data strongly support the absence of
spontaneous magnetization in the infinite-volume limit.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:07:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Liers",
"Frauke",
""
],
[
"Lukic",
"Jovanka",
""
],
[
"Marinari",
"Enzo",
""
],
[
"Pelissetto",
"Andrea",
""
],
[
"Vicari",
"Ettore",
""
]
] |
0707.1006 | Mark Saunders | M. Saunders, P. L. Halkyard, K. J. Challis, S. A. Gardiner | The manifestation of quantum resonances and antiresonances in a finite
temperature dilute atomic gas | 15 pages, 7 figures | Phys. Rev. A 76, 043415 (2007) | 10.1103/PhysRevA.76.043415 | null | physics.atom-ph nlin.CD | null | We investigate the effect of temperature on resonant and antiresonant
dynamics in a dilute atomic gas kicked periodically by a standing wave laser
field. Our numerical calculations are based on a Monte Carlo method for an
incoherent mixture of non-interacting plane waves, and show that the atomic
dynamics are highly sensitive to the initial momentum width of the gas. We
explain this sensitivity by examining the time evolution of individual atomic
centre of mass momentum eigenstates with varying quasimomentum, and we have
determined analytic expressions for the evolution of the second-order momentum
moment to illustrate the range of behaviours.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:08:56 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 12:07:51 GMT"
}
] | 2008-07-17T00:00:00 | [
[
"Saunders",
"M.",
""
],
[
"Halkyard",
"P. L.",
""
],
[
"Challis",
"K. J.",
""
],
[
"Gardiner",
"S. A.",
""
]
] |
0707.1007 | Mossadek Talby | Mossadek Talby | Bs Mixing and decays at the Tevatron | 6 pages, 8 figures | ECONF C070512:015,2007 | null | fpcp07_312 | hep-ex | null | This short review reports on recent results from CDF and D0 experiments at
the Tevatron collider on Bs mixing and the lifetimes of Bs and Lambdab.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:10:38 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 13:12:00 GMT"
}
] | 2011-03-23T00:00:00 | [
[
"Talby",
"Mossadek",
""
]
] |
0707.1008 | Mich\`ele Wigger | Amos Lapidoth, Shlomo Shamai (Shitz), Michele A. Wigger | On Cognitive Interference Networks | to appear in Proceedings of 2007 IEEE Information Theory Workshop
(ITW) in Lake Tahoe | null | 10.1109/ITW.2007.4313095 | null | cs.IT math.IT | null | We study the high-power asymptotic behavior of the sum-rate capacity of
multi-user interference networks with an equal number of transmitters and
receivers. We assume that each transmitter is cognizant of the message it
wishes to convey to its corresponding receiver and also of the messages that a
subset of the other transmitters wish to send. The receivers are assumed not to
be able to cooperate in any way so that they must base their decision on the
signal they receive only. We focus on the network's pre-log, which is defined
as the limiting ratio of the sum-rate capacity to half the logarithm of the
transmitted power. We present both upper and lower bounds on the network's
pre-log. The lower bounds are based on a linear partial-cancellation scheme
which entails linearly transforming Gaussian codebooks so as to eliminate the
interference in a subset of the receivers. Inter alias, the bounds give a
complete characterization of the networks and side-information settings that
result in a full pre-log, i.e., in a pre-log that is equal to the number of
transmitters (and receivers) as well as a complete characterization of networks
whose pre-log is equal to the full pre-log minus one. They also fully
characterize networks where the full pre-log can only be achieved if each
transmitter knows the messages of all users, i.e., when the side-information is
"full".
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:17:52 GMT"
}
] | 2016-11-15T00:00:00 | [
[
"Lapidoth",
"Amos",
"",
"Shitz"
],
[
"Shamai",
"Shlomo",
"",
"Shitz"
],
[
"Wigger",
"Michele A.",
""
]
] |
0707.1009 | Sebastian Liska | S. Liska, H. Gao, W. Chen, X. Qian | Search for the \phi-N bound state from \phi meson subthreshold
production | 5 pages, including 3 figures. Updated version of May '07 PRC paper
with some minor wording changes, Ref. [10] updated, additional
acknowledgement added, figures are revised after error found, the result and
conclusions remain the same | Phys.Rev.C75:058201,2007 | 10.1103/PhysRevC.75.058201 | null | nucl-ex | null | The subthreshold photoproduction of \phi mesons from heavy nuclear targets
has been suggested as a candidate to search for the \phi-N bound state, a
quantum chromodynamics molecular state. In this Brief Report, we present
detailed Monte Carlo studies to demonstrate the feasibility of this technique.
Further, we show that proton-induced subthreshold production of \phi meson from
heavy nuclear targets is also suitable for such a search.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 18:09:03 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liska",
"S.",
""
],
[
"Gao",
"H.",
""
],
[
"Chen",
"W.",
""
],
[
"Qian",
"X.",
""
]
] |
0707.1010 | Vincent L. Fish | Vincent L. Fish | OH Masers in G11.904-0.141 | 3 pages using emulateapj.cls including 1 table, accepted to ApJL | null | 10.1086/521400 | null | astro-ph | null | The massive star-forming region G11.904-0.141 is one of only 11 sources to
show maser emission in the highly-excited 13441 MHz transition of OH. VLBA
observations of the 1665, 1667, 4765, and 13441 MHz transitions of OH toward
G11.904-0.141 are presented. Masers are detected at 1665, 1667, and 4765 MHz,
but the 13441 MHz masers are not detected. Consistent magnetic field strengths
of approximately +3.5 mG are detected in the ground-state masers, in contrast
with a possible -3.0 mG magnetic field previously detected at 13441 MHz. The
variable 13441 MHz masers may be associated with an outflow.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:19:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fish",
"Vincent L.",
""
]
] |
0707.1011 | Martin Greiter | Martin Greiter | Statistical Phases and Momentum Spacings for One-Dimensional Anyons | 16 pages, 1 figure | Phys. Rev. B 79, 064409 (2009) [5 pages] | 10.1103/PhysRevB.79.064409 | null | quant-ph cond-mat.str-el math-ph math.MP | null | Anyons and fractional statistics are by now well established in
two-dimensional systems. In one dimension, fractional statistics has been
established so far only through Haldane's fractional exclusion principle, but
not via a fractional phase the wave function acquires as particles are
interchanged. At first sight, the topology of the configuration space appears
to preclude such phases in one dimension. Here we argue that the crossings of
one-dimensional anyons are always unidirectional, which makes it possible to
assign phases consistently and hence to introduce a statistical parameter
theta. The fractional statistics then manifests itself in fractional spacings
of the single-particle momenta of the anyons when periodic boundary conditions
are imposed. These spacings are given by Delta p = 2 pi hbar/L
(|theta|/pi+non-negative integer) for a system of length L. This condition is
the analogue of the quantisation of relative angular momenta according to
l_z=hbar(-theta/pi+2integer) for two-dimensional anyons.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:46:39 GMT"
}
] | 2009-02-12T00:00:00 | [
[
"Greiter",
"Martin",
""
]
] |
0707.1012 | Fernando Roig | F. Roig, D. Nesvorny, R. Gil-Hutton, D. Lazzaro | V-type asteroids in the middle Main Belt | Submitted to Icarus - 4 tables, 8 figures | null | 10.1016/j.icarus.2007.10.004 | null | astro-ph | null | The recent discovery of the first V-type asteroid in the middle belt, (21238)
1995WV7, located at ~2.54 AU, raises the question of whether it came from (4)
Vesta or not. In this paper, we present spectroscopic observations indicating
the existence of another V-type asteroid at ~2.53 AU, (40521) 1999RL95, and we
investigate the possibility that these two asteroids evolved from the Vesta
family to their present orbits by drifting in semi-major axis due to the
Yarkovsky effect. The main problem with this scenario is that the asteroids
need to cross the 3/1 mean motion resonance with Jupiter, which is highly
unstable. Combining numerical simulations of the orbital evolution, that
include the Yarkovsky effect, with Monte Carlo models, we compute the
probability of an asteroid of given diameter D to evolve from the Vesta family
and to cross over the 3/1 resonance, reaching a stable orbit in the middle
belt. Our results indicate that an asteroid like (21238) 1995WV7 has a low
probability of having evolved through this mechanism due to its large size (~5
km). However, the mechanism might explain the orbit of smaller bodies like
(40521) 1999RL95 (~3 km), provided that we assume that the Vesta family formed
> 3.5 Gy ago. We estimate that about 10% or more of the V-type bodies with D>1
km may come from the Vesta family by crossing over the 3/1 resonance. The
remaining 90% must have a different origin.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:34:54 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 21:14:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Roig",
"F.",
""
],
[
"Nesvorny",
"D.",
""
],
[
"Gil-Hutton",
"R.",
""
],
[
"Lazzaro",
"D.",
""
]
] |
0707.1013 | Gerardo Naumis | G.G. Naumis | Internal mobility edge in doped graphene: frustration in a renormalized
lattice | null | Phys. Rev. B 76, 1153403 (2007) | 10.1103/PhysRevB.76.153403 | null | cond-mat.mtrl-sci cond-mat.mes-hall | null | We show that an internal localization mobility edge can appear around the
Fermi energy in graphene by introducing impurities in the split-band regimen,
or by producing vacancies in the lattice. The edge appears at the center of the
spectrum and not at the band edges, in contrast with the usual picture of
localization. Such result is explained by showing that the bipartite nature of
lattice allows to renormalize the Hamiltonian, and the internal edge appears
because of frustration effects in the renormalized lattice. The size in energy
of the spectral region with localized states is similar in value to that
observed in narrow gap semiconductors.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:34:56 GMT"
}
] | 2011-02-04T00:00:00 | [
[
"Naumis",
"G. G.",
""
]
] |
0707.1014 | Johannes Felix Ebert | Johannes Ebert | The low-dimensional homotopy of the stable mapping class group | null | null | null | null | math.AT | null | Due to the deep work of Tillmann, Madsen, Weiss and Galatius, the cohomology
of the stable mapping class group $\gaminf$ is known with rational or finite
field coefficients. Little is known about the integral cohomology. In this
paper, we study the first four cohomology groups. Also, we compute the first
few steps of the Postnikov tower of $B \gaminf^+$, the Quillen plus
construction applied to $B \gaminf$. Our method relies on the Madsen-Weiss
theorem, a few known computations of stable homotopy groups of spheres and
projective spaces and on a certain action of the binary icosahedral group on a
surface. Using the latter, we can also describe an explicit geometric generator
of the third homotopy group $\pi_3 (B \gaminf)$.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:43:57 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Ebert",
"Johannes",
""
]
] |
0707.1015 | Jesko Sirker | S. Glocke, A. Kl\"umper, J. Sirker | The Half-Filled One-Dimensional Extended Hubbard Model: Phase diagram
and Thermodynamics | Reference and figure added | Phys. Rev. B 76, 155121 (2007) | 10.1103/PhysRevB.76.155121 | null | cond-mat.str-el | null | We study the thermodynamics of the one-dimensional extended Hubbard model at
half-filling using a density-matrix renormalization group method applied to
transfer matrices. We show that the various phase transitions in this system
can be detected by measuring usual thermodynamic quantities like the isothermal
compressibility and the uniform magnetic susceptibility. For the isothermal
compressibility we show that universal crossing points exist which allow to
accurately determine the line where the charge gap vanishes. By studying in
addition several correlation functions, we confirm the existence of a phase
with long-range dimer order (bond order) which has been a matter of debate for
several years. According to our calculations this phase is located in a narrow
region between the spin-density and charge-density wave phases up to a
tricritical point which we estimate to be at $U_t=6.7\pm 0.2$, $V_t =3.5\pm
0.1$. Our results for the phase diagram are in good agreement with the most
recent zero-temperature density-matrix renormalization group study, however,
they disagree in some important aspects from the most recent
Quantum-Monte-Carlo study.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:46:19 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Sep 2007 07:50:51 GMT"
}
] | 2007-11-04T00:00:00 | [
[
"Glocke",
"S.",
""
],
[
"Klümper",
"A.",
""
],
[
"Sirker",
"J.",
""
]
] |
0707.1016 | Michiel Wouters | M. Wouters, I. Carusotto, C. Ciuti | Spatial and spectral shape of inhomogeneous non-equilibrium
exciton-polariton condensates | 5 pages, 3 figures | null | 10.1103/PhysRevB.77.115340 | null | cond-mat.other | null | We develop a mean-field theory of the spatial profile and the spectral
properties of polariton condensates in nonresonantly pumped semiconductor
microcavities in the strong coupling regime. Predictions are obtained for both
the continuous-wave and the pulsed excitation regimes and the specific
signatures of the non-equilibrium character of the condensation process are
pointed out. A striking sensitivity of the condensate shape on the optical pump
spot size is demonstrated by analytical and numerical calculations, in good
quantitative agreement with recent experimental observations.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:55:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wouters",
"M.",
""
],
[
"Carusotto",
"I.",
""
],
[
"Ciuti",
"C.",
""
]
] |
0707.1017 | Mikhail Zubkov | B. L. G. Bakker, A. I. Veselov, M. A. Zubkov | Nambu monopoles in lattice Electroweak theory | LATEX | J. Phys. G: Nucl. Part. Phys. 36 (2009) 075008. | 10.1088/0954-3899/36/7/075008 | ITEP-LAT/2007-12 | hep-lat hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We considered the lattice electroweak theory at realistic values of $\alpha$
and $\theta_W$ and for large values of the Higgs mass. We investigated
numerically the properties of topological objects that are identified with
quantum Nambu monopoles. We have found that the action density near the Nambu
monopole worldlines exceeds the density averaged over the lattice in the
physical region of the phase diagram. Moreover, their percolation probability
is found to be an order parameter for the transition between the symmetric and
the broken phases. Therefore, these monopoles indeed appear as real physical
objects. However, we have found that their density on the lattice increases
with increasing ultraviolet cutoff. Thus we conclude, that the conventional
lattice electroweak theory is not able to predict the density of Nambu
monopoles. This means that the description of Nambu monopole physics based on
the lattice Weinberg - Salam model with finite ultraviolet cutoff is
incomplete. We expect that the correct description may be obtained only within
the lattice theory that involves the description of TeV - scale physics.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:56:19 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Mar 2008 08:44:54 GMT"
},
{
"version": "v3",
"created": "Wed, 2 Apr 2008 15:59:26 GMT"
},
{
"version": "v4",
"created": "Sat, 9 Aug 2008 18:10:39 GMT"
},
{
"version": "v5",
"created": "Mon, 6 Oct 2008 08:01:08 GMT"
},
{
"version": "v6",
"created": "Fri, 13 Mar 2009 15:40:42 GMT"
}
] | 2009-05-29T00:00:00 | [
[
"Bakker",
"B. L. G.",
""
],
[
"Veselov",
"A. I.",
""
],
[
"Zubkov",
"M. A.",
""
]
] |
0707.1018 | Richard L. Hall | Richard L. Hall | Solutions to the 1d Klein-Gordon equation with cutoff Coulomb potentials | 8 pages, 4 figures | Phys. Lett. A 372, 12 - 15 (2007) | 10.1016/j.physleta.2007.07.003 | CUQM-121 | math-ph math.MP | null | In a recent paper by Barton (J. Phys. A40, 1011 (2007)), the 1-dimensional
Klein-Gordon equation was solved analytically for the non-singular Coulomb-like
potential V_1(|x|) = -\alpha/(|x|+a). In the present paper, these results are
completely confirmed by a numerical formulation that also allows a solution for
an alternative cutoff Coulomb potential V_2(|x|) = -\alpha/|x|, ~|x| > a, and
otherwise V_2(|x|) = -\alpha/a.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:56:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hall",
"Richard L.",
""
]
] |
0707.1019 | Annalisa Calamida | A. Calamida (1 and 2), G. Bono (1), P.B. Stetson (3), L. M. Freyhammer
(4), S. Cassisi (5), F. Grundahl (6), A. Pietrinferni (5), M. Hilker (7), F.
Primas (7), T. Richtler (8), M. Romaniello (7), R. Buonanno (2), F. Caputo
(1), M. Castellani (1), C. E. Corsi (1), I. Ferraro (1), G. Iannicola (1), L.
Pulone (1) ((1) OAR/INAF, (2) Univ. Roma Tor Vergata, (3) HIA/NRC, (4) Univ.
Lancashire, (5) OACT/INAF, (6) Aarhus Univ., (7) ESO, (8) Univ. de
Concepcion) | Stroemgren photometry of Galactic Globular Clusters. I. New Calibrations
of the metallicity index | 51 pages, 19 figures, accepted for submission to ApJ | null | 10.1086/521424 | null | astro-ph | null | We present a new calibration of the Stroemgren metallicity index m1 using red
giant (RG) stars in 4 globular clusters (GCs:M92,M13,NGC1851,47Tuc) with
metallicity ranging from [Fe/H]=-2.2 to -0.7, marginally affected by reddening
(E(B-V)<0.04) and with accurate u,v,b,y photometry.The main difference between
the new metallicity-index-color (MIC) relations and similar relations available
in the literature is that we adopted the u-y/v-y colors instead of the
b-y.These colors present a stronger sensitivity to effective temperature, and
the MIC relations show a linear slope. The difference between photometric
estimates and spectroscopic measurements for RGs in M71,NGC288,NGC362,NGC6397,
and NGC6752 is 0.04+/-0.03dex (sigma=0.11dex). We also apply the MIC relations
to 85 field RGs with metallicity raning from [Fe/H]=-2.4 to -0.5 and accurate
reddening estimates. We find that the difference between photometric estimates
and spectroscopic measurements is-0.14+/-0.01dex (sig=0.17dex). We also provide
two sets of MIC relations based on evolutionary models that have been
transformed into the observational plane by adopting either semi-empirical or
theoretical color-temperature relations. We apply the semi-empirical relations
to the 9 GCs and find that the difference between photometric and spectroscopic
metallicities is 0.04+/-0.03dex (sig=0.10dex).A similar agreement is found for
the sample of field RGs, with a difference of -0.09+/-0.03dex (sig=0.19dex).The
difference between metallicity estimates based on theoretical relations and
spectroscopic measurements is -0.11+/-0.03dex (sig=0.14dex) for the 9 GGCs and
-0.24+/-0.03dex (sig=0.15dex) for the field RGs. Current evidence indicates
that new MIC relations provide metallicities with an intrinsic accuracy better
than 0.2dex.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:01:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Calamida",
"A.",
"",
"1 and 2"
],
[
"Bono",
"G.",
""
],
[
"Stetson",
"P. B.",
""
],
[
"Freyhammer",
"L. M.",
""
],
[
"Cassisi",
"S.",
""
],
[
"Grundahl",
"F.",
""
],
[
"Pietrinferni",
"A.",
""
],
[
"Hilker",
"M.",
""
],
[
"Primas",
"F.",
""
],
[
"Richtler",
"T.",
""
],
[
"Romaniello",
"M.",
""
],
[
"Buonanno",
"R.",
""
],
[
"Caputo",
"F.",
""
],
[
"Castellani",
"M.",
""
],
[
"Corsi",
"C. E.",
""
],
[
"Ferraro",
"I.",
""
],
[
"Iannicola",
"G.",
""
],
[
"Pulone",
"L.",
""
]
] |
0707.1020 | Claudius Gros | B. Edegger, V.N. Muthukumar, C. Gros | Gutzwiller-RVB Theory of High Temperature Superconductivity: Results
from Renormalised Mean Field Theory and Variational Monte Carlo Calculations | Review, Adv. Phys. (in press) | Advances in Physics, Volume 56, 927 (2007). | null | null | cond-mat.str-el cond-mat.supr-con | null | We review the Resonating Valence Bond (RVB) theory of high temperatur e
superconductivity using Gutzwiller projected wave functions that incorporate
strong correlations. After a general overview of the phenomenon of high
temperature superconductivity, we discuss Anderson's RVB picture and its
implementation by renormalised mean field theory (RMFT) and variational Monte
Carlo (VMC) techniques. We review RMFT and VMC results with an emphasis on
recent development s in extending VMC and RMFT techniques to excited states. We
compare results obtained from these methods with angle resolved photoemission
spectroscopy (ARPES) and scanning tunnelling microscopy (STM). We conclude by
summarising recent successes of this approach and discuss open problems that
need to be solved for a consistent and complete description of high temperature
superconductivity using Gutzwiller projected wave functions.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:07:28 GMT"
}
] | 2007-10-08T00:00:00 | [
[
"Edegger",
"B.",
""
],
[
"Muthukumar",
"V. N.",
""
],
[
"Gros",
"C.",
""
]
] |
0707.1021 | Cristina Lazzeroni | Cristina Lazzeroni | Trigger, reconstruction and physics performances in LHCb | Hadron Collider Physics Symposium (HCP06) Duke University Durham,
North Carolina; May 22-26, 2006 | null | null | null | hep-ex | null | LHCb is one of the four major experiments that will take data at the LHC, due
to start operation in 2007. The primary aims of LHCb are to perform precision
tests of CP violation and to search for new physics in b hadron decays. About
10^12 bb pairs will be produced in LHCb per 10^7 seconds (a nominal year) in pp
collisions with a luminosity of 2x10^32 cm^-2 s^-1. A large, high-purity sample
of b hadrons, decaying in a variety of channels, will be accumulated. LHCb will
perform a detailed study of B meson mixing, precise measurements of the angles
of the unitary triangle and investigations of rare decays in b hadrons, looking
for new physics in loop-induced processes. The LHCb detector is optimised to
reach these physics goals. Here a brief description of the reconstruction
performance is given, and the sensitivities in typical channels for the study
of Bs mixing, CP violation and rare decays are summarised.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 16:11:12 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Lazzeroni",
"Cristina",
""
]
] |
0707.1022 | James M. Stone | James M. Stone and Thomas A. Gardiner | Nonlinear Evolution of the Magnetohydrodynamic Rayleigh-Taylor
Instability | 25 pages, accepted by Physics of Fluids, online version of journal
has high resolution figures | null | 10.1063/1.2767666 | null | astro-ph | null | We study the nonlinear evolution of the magnetic Rayleigh-Taylor instability
using three-dimensional MHD simulations. We consider the idealized case of two
inviscid, perfectly conducting fluids of constant density separated by a
contact discontinuity perpendicular to the effective gravity g, with a uniform
magnetic field B parallel to the interface. Modes parallel to the field with
wavelengths smaller than l_c = [B B/(d_h - d_l) g] are suppressed (where d_h
and d_l are the densities of the heavy and light fluids respectively), whereas
modes perpendicular to B are unaffected. We study strong fields with l_c
varying between 0.01 and 0.36 of the horizontal extent of the computational
domain. Even a weak field produces tension forces on small scales that are
significant enough to reduce shear (as measured by the distribution of the
amplitude of vorticity), which in turn reduces the mixing between fluids, and
increases the rate at which bubbles and finger are displaced from the interface
compared to the purely hydrodynamic case. For strong fields, the highly
anisotropic nature of unstable modes produces ropes and filaments. However, at
late time flow along field lines produces large scale bubbles. The kinetic and
magnetic energies transverse to gravity remain in rough equipartition and
increase as t^4 at early times. The growth deviates from this form once the
magnetic energy in the vertical field becomes larger than the energy in the
initial field. We comment on the implications of our results to Z-pinch
experiments, and a variety of astrophysical systems.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:27:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stone",
"James M.",
""
],
[
"Gardiner",
"Thomas A.",
""
]
] |
0707.1023 | Michael Fogler | M. M. Fogler, D. S. Novikov, B. I. Shklovskii | Screening of a hypercritical charge in graphene | (v1) 4 pages, 1 figure (v2) Much improved introduction; extended
range of numerics | Phys. Rev. B 76, 233402 (2007) | 10.1103/PhysRevB.76.233402 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | Screening of a large external charge in graphene is studied. The charge is
assumed to be displaced away or smeared over a finite region of the graphene
plane. The initial decay of the screened potential with distance is shown to
follow the 3/2 power. It gradually changes to the Coulomb law outside of a
hypercritical core whose radius is proportional to the external charge.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:30:39 GMT"
},
{
"version": "v2",
"created": "Sat, 7 Jul 2007 21:28:21 GMT"
},
{
"version": "v3",
"created": "Wed, 29 Aug 2007 14:46:44 GMT"
}
] | 2007-12-05T00:00:00 | [
[
"Fogler",
"M. M.",
""
],
[
"Novikov",
"D. S.",
""
],
[
"Shklovskii",
"B. I.",
""
]
] |
0707.1024 | Friedrich Konrad Roepke | F. K. Roepke, W. Hillebrandt, W. Schmidt, J. C. Niemeyer, S. I.
Blinnikov, P. A. Mazzali | A three-dimensional deflagration model for Type Ia supernovae confronted
with observations | 8 pages, 5 figures, accepted for publication in the ApJ | null | 10.1086/521347 | null | astro-ph | null | A simulation of the thermonuclear explosion of a Chandrasekhar-mass C+O white
dwarf, the most popular scenario of a type Ia supernova (SN Ia), is presented.
The underlying modeling is pursued in a self-consistent way, treating the
combustion wave as a turbulent deflagration using well tested methods developed
for laboratory combustion and based on the concept of `large eddy simulations'
(LES). Such consistency requires to capture the onset of the turbulent cascade
on resolved scales. This is achieved by computing the dynamical evolution on a
1024$^3$ moving grid, which resulted in the best-resolved three-dimensional SN
Ia simulation carried out thus far, reaching the limits of what can be done on
present supercomputers. Consequently, the model has no free parameters other
than the initial conditions at the onset of the explosion, and therefore it has
considerable predictive power. Our main objective is to determine to which
extent such a simulation can account for the observations of normal SNe Ia.
Guided by previous simulations with less resolution and a less sophisticated
flame model, initial conditions were chosen that yield a reasonably strong
explosion and a sufficient amount of radioactive nickel for a bright display.
We show that observables are indeed matched to a reasonable degree. In
particular, good agreement is found with the light curves of normal SNe Ia.
Moreover, the model reproduces the general features of the abundance
stratification as inferred from the analysis of spectra. This indicates that it
captures the main features of the explosion mechanism of SNe Ia. However, we
also show that even a seemingly best-choice pure deflagration model has
shortcomings that indicate the need for a different mode of nuclear burning at
late times, perhaps the transition to a detonation at low density.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:31:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Roepke",
"F. K.",
""
],
[
"Hillebrandt",
"W.",
""
],
[
"Schmidt",
"W.",
""
],
[
"Niemeyer",
"J. C.",
""
],
[
"Blinnikov",
"S. I.",
""
],
[
"Mazzali",
"P. A.",
""
]
] |
0707.1025 | Sergei Fedorenko | Sergei Fedorenko | The star trellis decoding of Reed-Solomon codes | 6 pages. Proceedings of the XI international symposium on problems of
redundancy in information and control systems at St.Petersburg, Russia, July
2007, pp.58-61 | null | null | null | cs.IT math.IT | null | The new method for Reed-Solomon codes decoding is introduced. The method is
based on the star trellis decoding of the binary image of Reed-Solomon codes.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:32:56 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Fedorenko",
"Sergei",
""
]
] |
0707.1026 | Joseph Incandela | Joseph R. Incandela | The Status of CMS | 7 pages, 8 figures, Proceedings for the 2006 Hadron Collider Physics
conference at Duke University | null | null | null | physics.ins-det | null | After a brief overview of the Compact Muon Solenoid (CMS) experiment, the
status of construction, installation and commissioning is described. Very good
progress has been achieved in the past year. Though many significant challenges
still lie ahead, CMS should be ready for recording data from first collisions
in the Large Hadron Collider (LHC) accelerator complex at CERN
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:33:36 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Incandela",
"Joseph R.",
""
]
] |
0707.1027 | George Seabroke | G. M. Seabroke, G. Gilmore (Institute of Astronomy, University of
Cambridge, UK) | Re-visiting the relations: Galactic thin disc age-velocity dispersion
relation | Accepted for publication in MNRAS, 24 pages, 20 figures | null | 10.1111/j.1365-2966.2007.12210.x | null | astro-ph | null | The velocity dispersion of stars in the solar neighbourhood thin disc
increases with time after star formation. Nordstrom et al. (2004) is the most
recent observational attempt to constrain the age-velocity dispersion relation.
They fitted the age-velocity dispersion relations of each Galactic cardinal
direction space velocity component, U (towards the Galactic centre), V (in the
direction of Galactic rotation) and W (towards the North Galactic Pole), with
power laws and interpreted these as evidence for continuous heating of the disc
in all directions throughout its lifetime. We re-visit these relations with
their data and use Famaey et al. (2005) to show that structure in the local
velocity distribution function distorts the in-plane (U and V) velocity
distributions away from Gaussian so that a dispersion is not an adequate
parametrization of their functions. The age-sigma(W) relation can however be
constrained because the sample is well phase-mixed vertically. We do not find
any local signature of the stellar warp in the Galactic disc. Vertical disc
heating does not saturate at an early stage. Our new result is that a power law
is not required by the data: disc heating models that saturate after ~ 4.5 Gyr
are equally consistent with observations.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 17:34:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Seabroke",
"G. M.",
"",
"Institute of Astronomy, University of\n Cambridge, UK"
],
[
"Gilmore",
"G.",
"",
"Institute of Astronomy, University of\n Cambridge, UK"
]
] |
0707.1028 | Donald Spector | Donald Spector | Minimal Length Uncertainty Relations and New Shape Invariant Models | 11 pages, no figures | null | 10.1063/1.2955795 | NSF-KITP-07-107 | quant-ph hep-th physics.atom-ph | null | This paper identifies a new class of shape invariant models. These models are
based on extensions of conventional quantum mechanics that satisfy a
string-motivated minimal length uncertainty relation. An important feature of
our construction is the pairing of operators that are not adjoints of each
other. The results in this paper thus show the broader applicability of shape
invariance to exactly solvable systems.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 18:06:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Spector",
"Donald",
""
]
] |
0707.1029 | Ian Gatland | Ian R. Gatland | Systematic approximations for the period of a finite amplitude pendulum | 9 pages (including references and a table) | null | null | null | physics.class-ph | null | The standard series expansion for the period of a finite amplitude pendulum
as a function of energy (and hence amplitude) provides a lower limit on the
period when the series is truncated. An adjustment to the last term in the
truncated series to take account of the dropped terms improves the accuracy of
the approximation and provides an upper limit on the period. More accurate
approximations can then be obtained using intermediate expressions.
| [
{
"version": "v1",
"created": "Fri, 6 Jul 2007 18:03:33 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Gatland",
"Ian R.",
""
]
] |
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