October 2002 arXiv papers — page 8
Showing 701–800 of 3,443 papers
C. Weber, H. Eberl, W. Majerotto
We discuss the full electroweak one-loop corrections to the decay of the pseudoscalar Higgs boson A^0 into two sfermions within the Minimal Supersymmetric Standard Model. In particular, we consider the sfermions of the third generation, stops, sbottoms, and staus, including the left-right mixing. The electroweak corrections can go up to ~15% and can therefor
B. Melic, R. Rückl
The method of QCD light-cone sum rules is used to calculate soft nonfactorizable contributions to the decay amplitude for B -> J/psi K. The result confirms expectations that in color-suppressed decays nonfactorizable corrections can be sizable.
Marco Battaglia, Stefania De Curtis, Daniele Dominici
Several models predict the existence of new vector resonances in the multi-TeV region, which can be produced in high energy e+e- collisions in the s-channel. In this paper we review the existing limits on the masses of these resonances from LEP/SLC and TEVATRON data and from atomic parity violation in some specific models. We study the potential of a multi-T
G. Belanger
micrOMEGAs is a program that calculates the relic density of the lightest supersymmetric particle in the MSSM. All tree-level processes for the annihilation of the LSP are included as well as all possible coannihilation processes. The cross-sections extracted from CompHEP are calculated exactly. Relativistic formulae for the thermal average are used and care
Jonivar Skullerud, Jan Smit, Anders Tranberg
Results are presented of a numerical study of the distribution of W-bosons generated in a tachyonic electroweak pre-heating transition
Andreas Nyffeler
We briefly review the current status of the hadronic light-by-light scattering correction to the muon g-2. Then we present our semi-analytical evaluation of the pion-pole contribution, using a description of the pion-photon-photon transition form factor based on large-N_C and short-distance properties of QCD. We derive a two-dimensional integral representati
D. Anchishkin, V. Khryapa, V. Ruuskanen
We analyze the dilepton emission rates from the hot pion gas confined to a finite space-time volume. Two models of pion(+) pion(-) annihilation to dileptons are under consideration. The first model mimics an extreme influence of the dense hadron environment on the rho-meson mean free path and mean life time. The second model deals with the standard concept o
K. Terasaki
In consistency with the b --> c type of (quasi) two body decays, recently observed two body decays of B mesons are studied in a hybrid perspective in which their amplitude is given by a sum of factorizable and non-factorizable ones, and a role of the latter in these decays are discussed.
The technique of inverse Mellin transform for processes occurring in a background magnetic field
hep-phGuey-Lin Lin
We develop the technique of inverse Mellin transform for processes occurring in a background magnetic field. We show by analyticity that the energy (momentum) derivatives of a field theory amplitude at the zero energy (momentum) is equal to the Mellin transform of the absorptive part of the amplitude. By inverting the transform, the absorptive part of the am
V. G. Bornyakov, D. A. Komarov, M. I. Polikarpov, A. I. Veselov
We perform the careful study of the Gribov copies problem in SU(2) lattice gauge theory for maximal direct and maximal indirect center projections. We find that this problem is much more severe than it was thought before. The projected string tension is not in agreement with the physical string tension. We also show that the particle--like objects, nexuses,
R. H. Bernstein
The NuTeV Collaboration has measured the electroweak parameters sin^2 theta_W and rho in neutrino-nucleon deep-inelastic scattering using a sign-selected beam. The nearly pure neutrino or antineutrino beams that result provide many of the cancellations of systematics associated with the Paschos-Wolfenstein relation. The extracted result for sin^2 theta_W(on-
U. Egede
We report a preliminary result for D0-D0bar mixing and the doubly Cabibbo suppressed decay rate R_D based on an analysis of D0 -> K+ pi- decays from 57.1 inverse fb of data collected at or just below the Y(4S) resonance with the BaBar detector at the PEP-II collider. We set 95% confidence limits for the mixing parameters x'^2 and y' and find that our
Richard Nisius
The status of the measurements and the theoretical developments concerning the hadronic structure of the photon are briefly summarised.
A. Sandoval-Villalbazo, L. S. Garcia-Colin
Einstein's field equations in FRW space-times are coupled to the BGK equation in order to derive the stress energy tensor including dissipative effects up to second order in the thermodynamical forces. The space-time is assumed to be matter-dominated, but in a low density regime for which a second order (Burnett) coefficient becomes relevant. Cosmologica
Makoto Narita
We show a global existence theorem for Einstein-matter equations of $T^{3}$-Gowdy symmetric spacetimes with stringy matter. The areal time coordinate is used. It is shown that this spacetime has a crushing singularity into the past. From these results we can show that the spacetime is foliated by compact hypersurfaces of constant mean curvature.
M. K. Mak, T. Harko
Three solutions of the Brans-Dicke theory with a self-interacting quartic potential and perfect fluid distribution are presented for a spatially flat geometry. The physical behavior is consistent with the recent cosmological scenario favored by type Ia supernova observations, indicating an accelerated expansion of the Universe.
Timothy Porter
Recent advances in Multiagent Systems (MAS) and Epistemic Logic within Distributed Systems Theory, have used various combinatorial structures that model both the geometry of the systems and the Kripke model structure of models for the logic. Examining one of the simpler versions of these models, interpreted systems, and the related Kripke semantics of the lo
A. K. Hartmann, M. A. Moore
The energy of a droplet of linear extent l in the droplet theory of spin glasses goes as l^θ for large l. It is shown by numerical studies of large droplets in two-dimensional systems that this formula needs to be modified by the addition of a scaling correction l^{-ω} in order to accurately describe droplet energies at the length scales currently probed in
Statistics of the critical percolation backbone with spatial long-range correlations
cond-mat.stat-mechA. D. Araújo, A. A. Moreira, R. N. Costa Filho, J. S. Andrade,
We study the statistics of the backbone cluster between two sites separated by distance $r$ in two-dimensional percolation networks subjected to spatial long-range correlations. We find that the distribution of backbone mass follows the scaling {\it ansatz}, $P(M_B)\sim M_B^{-(α+1)}f(M_B/M_0)$, where $f(x)=(α+ ηx^η) \exp(-x^η)$ is a cutoff function, and $M_0
Thermodynamic Compressibility of a Two-Dimensional Electron System: Signature of a Droplet State
cond-mat.str-elS. C. Dultz, B. Alavi, H. W. Jiang
We have used a field-penetration method to measure thermodynamic compressibility of a moderately interacting two-dimensional electron system ($r_{s}$ $\approx$ 0.5-3) in a three terminal GaAs/AlGaAs device, fabricated with an epitaxial lift-off technique. We found that the density and temperature dependencies of the compressibility are qualitatively differen
Petr Král
We theoretically demonstrate that atomically-precise ``nanoscale processing" can be reproducibly performed by adaptive laser pulses. We present the new approach on the controlled welding of crossed carbon nanotubes, giving various metastable junctions of interest. Adaptive laser pulses could be also used in preparation of other hybrid nanostructures.
Analytical solution of 1D lattice gas model with infinite number of multiatom interactions
cond-mat.mtrl-sciV. I. Tokar, H. Dreyssé
We consider a 1D lattice gas model in which the atoms interact via an infinite number of cluster interactions within contiguous atomic chains plus the next nearest neighbor pairwise interaction. All interactions are of arbitrary strength. An analytical expression for the size distribution of atomic chain lengths is obtained in the framework of the canonical
Anisotropic and incommensurate spin fluctuations in hcp iron and some other nearly magnetic metals
cond-mat.mtrl-sciV. Thakor, J. B. Staunton, J. Poulter, S. Ostanin
We present an ab initio theoretical formalism for the static paramagnetic spin susceptibility of metals at finite temperatures. Since relativistic effects, e.g. spin-orbit coupling, are included, we can identify the anisotropy or easy axes of the spin fluctuations. Our calculations find hcp-iron to be unstable to in ab-plane, incommensurate anti-ferromagneti
Vortex matter in layered superconductors without Josephson coupling: numerical simulations within a mean-field approach
cond-mat.supr-conHans Fangohr, Alexei E. Koshelev, Matthew J. W. Dodgson
We study vortex matter in layered superconductors in the limit of zero Josephson coupling. The long range of the interaction between pancake vortices in the c-direction allows us to employ a mean-field method: all attractive inter-layer interactions are reduced to an effective substrate potential, which pancakes experience in addition to the same-layer panca
Dirk Kurtsiefer
The following article deals with the critical value p_c of the three-dimensional bootstrap percolation. We will check the behavior of p_c for different lengths of the lattice and additionally we will scale p_c in the limit of an infinite lattice.
Dynamics of trapped two-component Fermi gas: temperature dependence of the transition from collisionless to collisional regime
cond-mat.stat-mechF. Toschi, P. Vignolo, S. Succi, M. P. Tosi
We develop a numerical method to study the dynamics of a two-component atomic Fermi gas trapped inside a harmonic potential at temperature T well below the Fermi temperature Tf. We examine the transition from the collisionless to the collisional regime down to T=0.2 Tf and find good qualitative agreement with the experiments of B. DeMarco and D.S. Jin [Phys.
Picco Marco, Ritort Felix, Sales Marta
A new approach to determine the value of the zero-temperature thermal exponent theta in spin glasses is presented. It consists in describing the energy level spectrum in spin glasses only in terms of the properties of the lowest energy droplets and the lowest droplet exponents (LDEs) lambda_l,theta_l that describe the statistics of their sizes and gaps. We s
G. Oshanin, S. F. Burlatsky
We study equilibrium properties of a catalytically-activated annihilation $A + A \to 0$ reaction taking place on a one-dimensional chain of length $N$ ($N \to \infty$) in which some segments (placed at random, with mean concentration $p$) possess special, catalytic properties. Annihilation reaction takes place, as soon as any two $A$ particles land onto two
Anders Johansen
Statistics of drawdowns (loss from the last local maximum to the next local minimum) plays an important role in risk assessment of investment strategies. As they incorporate higher ($>$ two) order correlations, they offer a better measure of real market risks than the variance or other cumulants of daily (or some other fixed time scale) of returns. Previous
L. A. Manakova
In the present paper it is shown that the interaction between oscillations of a double-well trappedcondensate and excited Josephson states corresponding to a large enough initial disbalance of the particle number generates their bound state. The bound state can realize an absolute minimum of the thermodynamic energy. The existence of the equilibrium bound st
M. Roger, P. Guenoun, F. Muller, L. Belloni
The concentration profiles of monomers and counterions in star-branched polyelectrolyte micelles are calculated through Monte-Carlo simulations, using the simplest freely-jointed chain model. We have investigated the onset of different regimes corresponding to the spherical and Manning condensation of counterions as a function of the strength of the Coulomb
W. Janke, D. A. Johnston, R. Kenna
Motivated by previous observations that geometrizing statistical mechanics offers an interesting alternative to more standard approaches,we have recently calculated the curvature (the fundamental object in this approach) of the information geometry metric for the Ising model on an ensemble of planar random graphs. The standard critical exponents for this mod
Dominance of excitation continuum in the longitudinal spectrum of weakly coupled Heisenberg S=1/2 chains
cond-mat.str-elA. Zheludev, K. Kakurai, T. Masuda, K. Uchinokura
A low-field spin flop transition in the quasi one-dimensional antiferromagnet \ba is exploited to study the polarization dependence of low-energy magnetic excitations. The measured longitudinal spectrum is best described as single broad continuum, with no sharp ``longitudinal mode'', in apparent contradiction with the commonly used chain-MF/RPA theor
Masaaki Nakamura
We discuss relation between three different methods to identify topologically distinct short-range valence-bond ground states in spin-$\frac12$ two-leg ladders: the string order parameters, the level-crossing method, and the ground-state expectation value of the twist operator. For this purpose we reexamine a phase transition in the frustrated spin ladder. W
N. Sator
This article concerns the correspondence between thermodynamics and the morphology of simple fluids in terms of clusters. Definitions of clusters providing a geometric interpretation of the liquid-gas phase transition are reviewed with an eye to establishing their physical relevance. The author emphasizes their main features and basic hypotheses, and shows h
Olivier Cepas, Ross H. McKenzie
We consider the possibility that the electrons injected into organic field-effect transistors are strongly correlated. A single layer of acenes can be modelled by a Hubbard Hamiltonian similar to that used for the kappa-(BEDT-TTF)(2)X family of organic superconductors. The injected electrons do not necessarily undergo a transition to a Mott insulator state a
A. A. Suchkov
I have isolated a population of numerous F stars that appear to be pre-main-sequence (PMS). The candidate PMS stars have been identified using CM diagram, reddening, flux excess in the UV and near-infrared, and luminosity anomaly. Negative luminosity anomaly and excessive UV flux for many of these stars is suggestive of accretion disks, while the NIR excess
Extrasolar Planets in Mean-Motion Resonance: Apses Alignment and Asymmetric Stationary Solutions
astro-phC. Beauge, S. Ferraz-Mello, T. A. Michtchenko
In recent years several pairs of extrasolar planets have been discovered in the vicinity of mean-motion commensurabilities. In some cases, such as the Gliese 876 system, the planets seem to be trapped in a stationary solution, the system exhibiting a simultaneous libration of the resonant angle theta_1 = 2 lambda_2 - lambda_1 - varpi_1 and of the relative po
Smita Mathur, David H. Weinberg, Xuelei Chen
We present Chandra observations that provide the most direct evidence to date for the pervasive, moderate density, shock-heated intergalactic medium predicted by leading cosmological scenarios. We also comment briefly on future observations with Constellation-X.
C. Da Rocha, C. Mendes de Oliveira, M. Bolte, B. L. Ziegler
We have studied globular cluster systems (GCSs) around elliptical galaxies in Hickson compact groups using multi-band deep, high quality images from Keck, VLT and CFHT. Analyzing the luminosity functions, specific frequencies, color and spatial distributions, we could determine the properties of the GCSs of those galaxies and trace their star formation histo
M. C. Aller, D. O. Richstone
Supermassive black holes are thought to be relics of quasars, and their numbers and masses are therefore related to the quasar luminosity function and its evolution with redshift. We have used the relationship between black hole mass and bulge velocity dispersion (the M_bullet - sigma relation) to make an improved estimate of the mass density and mass spectr
John Raymond, Parviz Ghavamian, Ravi Sankrit, William Blair
Spatial and spectral profiles of O VI emission behind a shock wave on the northern edge of the Cygnus Loop were obtained with the FUSE satellite. The velocity width of the narrowest O VI profile places a tight constraint on the electron-ion and ion-ion thermal equilibration in this 350 $\rm km s^{-1}$ collisionless shock. Unlike faster shocks in SN1006 and i
R. V. E. Lovelace, H. Li, A. V. Koldoba, G. V. Ustyugova
We give further considerations on the problem of the evolution of a coronal, force-free magnetic field which threads a differentially rotating, conducting Keplerian disk, extending the work of Li {\it et al.} (2001). This situation is described by the force-free Grad-Shafranov (GS) equation for the flux function $Ψ(r,z)$ which labels the poloidal field lines
Christian R. Kaiser, Marcus Brueggen, James J. Binney
We present a simple analytical model and the results of numerical simulations supporting the idea of periodical heating of cluster gas by AGN outflows. We show why, under this assumption, we are extremely unlikely to observe clusters containing gas with a temperature below about 1 keV. We review the results from numerical hydro-simulations studying the mecha
David Weldrake, Erwin de Blok, Fabian Walter
We present high resolution rotation curves of the local group dwarf irregular galaxy NGC 6822 obtained with the Australia Telescope Compact Array. Our best curves have an angular resolution of 8'' or 20 pc and contain some 250 independent points. The stellar and gas components of NGC 6822 cannot explain the shape of the curve, except for the very inn
Carlo Lari, Mattia Vaccari, Giulia Rodighiero, Dario Fadda
The techniques and software tools developed for the reduction and analysis of ISO-CAM/PHOT data with the LARI method are presented. The method, designed for the detection of faint sources in ISO raster observations, is based on the assumption of the existence of two different time scales in the detectors' transient behaviour, accounting either for fast o
RX J1039.7-0507: A New Intermediate Polar and Probable Recent Nova, possessing a large Reflection Effect
astro-phPatrick A. Woudt, Brian Warner
The ROSAT source RX J1039.7-0507, known from its optical spectrum to be a Cataclysmic Variable star, is shown from high speed photometry to have an orbital period of 1.574 h. The system has a nearly sinusoidal photometric modulation with a range of 1.1 mag which we interpret as the reflection effect caused by a very hot white dwarf primary. This suggests tha
Jeroen Homan, Marc Klein-Wolt, Sabrina Rossi, Jon M. Miller
We report the detection of high frequency variability in the black hole X-ray transient XTE J1650-500. A quasi-periodic oscillation (QPO) was found at 250 Hz during a transition from the hard to the soft state. We also detected less coherent variability around 50 Hz, that disappeared when the 250 Hz QPO showed up. There are indications that when the energy s
M. F. Aller, H. D. Aller, P. A. Hughes, R. M. Plotkin
Monitoring results are presented for the Stangellini 1 Jy GHz-peaked-spectrum source sample, illustrating that several members exhibit variability in total flux and/or linear polarization over timescales of order a decade. The variability occurs while the spectrum, based on the integrated fluxes, remains steep and characteristic of a transparent source. Tota
P. Marigo, C. Chiosi, L. Girardi, R. -P. Kudritzki
We discuss the evolutionary properties of primordial massive and very massive stars, supposed to have formed from metal-free gas. Stellar models are presented over a large range of initial masses (8 Msun <= Mi <= 1000 Msun), covering the hydrogen- and helium-burning phases up to the onset of carbon burning. In most cases the evolution is followed at constant
N. L. Homeier, R. D. Blum, P. S. Conti, A. Damineli
Initial results, techniques, and rationale for a near-infrared survey of evolved emission-line stars toward the Galactic Center are presented. We use images taken through narrow-band emission-line and continuum filters to select candidates for spectroscopic follow-up. The filters are optimized for the detection of Wolf-Rayet stars and other objects which exh
Michael Kuhlen, Stan E. Woosley, Gary A. Glatzmaier
After briefly describing the anelastic approximation and Glatzmaier's code, we present results from our preliminary studies of core convection during the hydrogen burning phase of a 15 solar mass star, as well as our most recent results concerning convection in the oxygen shell of a 25 solar mass star.
Anatoly Svidzinsky
The paper has been withdrawn because a new, substantially revised version of the theory of neutron star radiation is completed by the author.
Alexandre S. Martinez, Osame Kinouchi, Sebastian Risau-Gusman
A random walk is performed on a disordered landscape composed of $N$ sites randomly and uniformly distributed inside a $d$-dimensional hypercube. The walker hops from one site to another with probability proportional to $\exp [- βE(D)]$, where $β= 1/T$ is the inverse of a formal temperature and $E(D)$ is an arbitrary cost function which depends on the hop di
Masahide Yamaguchi, Jun'ichi Yokoyama
We clarify the quantitative nature of the cosmological evolution of a global string network, that is, the energy density, peculiar velocity, velocity squared, Lorentz factor, formation rate of loops, and emission rate of Nambu-Goldstone bosons, based on a new type of numerical simulation of scalar fields in Eulerian meshes. We give a detailed explanation of
Guido Altarelli, Ferruccio Feruglio, Isabella Masina
We present a quantitative study of the ability of models with different levels of hierarchy to reproduce the solar neutrino solutions, in particular the LA solution. As a flexible testing ground we consider models based on SU(5)xU(1)_F. In this context, we have made statistical simulations of models with different patterns from anarchy to various types of hi
I. L. Buchbinder, E. A. Ivanov, A. Yu. Petrov
Using the covariant N=2 harmonic supergraph techniques we calculate the one-loop low-energy effective action of N=4 super-Yang-Mills theory in Coulomb branch with gauge group SU(2) spontaneously broken down to U(1). The full dependence of the low-energy effective action on both the hypermultiplet and gauge fields is determined. The direct quantum calculation
Michael Nauenberg
During the past dozen years there have been numerous articles on a relation between entropy and probability which is non-additive and has a parameter $q$ that depends on the nature of the thermodynamic system under consideration. For $q=1$ this relation corresponds to the Boltzmann-Gibbs entropy, but for other values of $q$ it is claimed that it leads to a f
Yimin Jiang, Mario Liu
An self-contained elastic theory is derived which accounts both for mechanical yield and shear-induced volume dilatancy. Its two essential ingredients are thermodynamic instability and the dependence of the elastic moduli on compression.
Jiunn-Wei Chen, Karsten M. Heeger, R. G. Hamish Robertson
We analyze the Sudbury Neutrino Observatory (SNO) and Super-Kamiokande (SK) data on charged current (CC), neutral current (NC) and neutrino electron elastic scattering (ES) reactions to constrain the leading weak axial two-body current parameterized by L_1A. This two-body current is the dominant uncertainty of every low energy weak interaction deuteron break
Atom-Atom Scattering Under Cylindrical Harmonic Confinement: Numerical and Analytical Studies of the Confinement Induced Resonance
cond-matT. Bergeman, M. G. Moore, M. Olshanii
In a recent article [M. Olshanii, Phys. Rev. Lett. {\bf 81}, 938 (1998)], an analytic solution of atom-atom scattering with a delta-function pseudopotential interaction in the presence of transverse harmonic confinement yielded an effective coupling constant that diverged at a `confinement induced resonance.' In the present work, we report numerical resu
Nick Dorey, Timothy J. Hollowood, S. Prem Kumar
We investigate an exactly marginal N=1 supersymmetric deformation of SU(N) N=4 supersymmetric Yang-Mills theory discovered by Leigh and Strassler. We use a matrix model to compute the exact superpotential for a further massive deformation of the U(N) Leigh-Strassler theory. We then show how the exact superpotential and eigenvalue spectrum for the SU(N) theor
Francisco O. Durães, Su Houng Lee, Fernando S. Navarra, Marina Nielsen
We compute the $J/ψπ\to {charmed mesons}$ cross section using QCD sum rules. This cross section is important to distinguish the suppression in the production of $J/ψ$ through the dissociation by comoving pions and through the formation of quark-gluon plasma. Our sum rules for the $J/ψπ\to \bar{D} D^*$, $D \bar{D}^*$, ${\bar D}^* D^*$ and ${\bar D} D$ hadroni
Ana M. Curiel, Maria J. Herrero, David Temes
We study the flavour changing neutral Higgs boson decays that can be induced from genuine supersymmetric particles at the one-loop level and within the context of the Minimal Supersymmetric Standard Model. We consider all the possible flavour changing decay channels of the three neutral Higgs bosons into second and third generation quarks, and focus on the S
F. Ozon, T. Narita, A. Knaebel, G. Debrégeas
We study the effect of shear on the aging dynamics of a colloidal suspension of synthetic clay particles. We find that a shear of amplitude $γ$ reduces the relaxation time measured just after the cessation of shear by a factor $\exp(-γ/γ_c)$, with $γ_c \sim 5%$, and is independent of the duration and the frequency of the shear. This simple law for the rejuve
HongSheng Zhao, Rodrigo Ibata, Geraint Lewis, Mike Irwin
Although a decade of microlensing searches towards the Large Magellanic Cloud (LMC) has detected 13-25 possible microlensing events, the nature and the location of the lenses, being either halo machos or LMC stars, remains a subject of debate. The star-star lensing models generically predict the existence of a small population (more than about 5 percent of s
Remke Kloosterman
We describe in terms of the j-invariant all elliptic surfaces pi: X -> C with a section, such that h^{1,1}(X)=rank NS(X) and the Mordell-Weil group of pi is finite. We use this to give a complete solution to infinitesimal Torelli for elliptic surfaces with a section over P^1.
Mirror matter admixtures and isospin breaking in the ΔI=1/2 rule in Ω^- two body non-leptonic decays
hep-phG. Sanchez-Colon, R. Huerta, A. Garcia
We discuss a description of Ω^- two body non-leptonic decays based on possible, albeit tiny, admixtures of mirror matter in ordinary hadrons. The ΔI=1/2 rule enhancement is obtained as a result of isospin symmetry and, more importantly, the rather large observed deviations from this rule result from small isospin breaking. This analysis lends support to the
D. Kharzeev, E. Levin, L. McLerran
We argue that the suppression of high p_t hadrons discovered recently in heavy ion collisions at RHIC may be a consequence of saturation in the Color Glass Condensate. We qualitatively and semi-quantitatively describe the data, in particular, the dependence upon the number of nucleon participants. We show that if parton saturation sets in at sufficiently sma
K. G. Sandeman, G. G. Lonzarich, A. J. Schofield
We introduce a simple but powerful zero temperature Stoner model to explain the unusual phase diagram of the ferromagnetic superconductor, UGe2. Triplet superconductivity is driven in the ferromagnetic phase by tuning the majority spin Fermi level through one of two peaks in the paramagnetic density of states (DOS). Each peak is associated with a metamagneti
Nikos Papanikolaou
We present a theoretical study of the ballistic magnetoresistance in Ni contacts using first-principles, atomistic electronic-structure calculations. In particular we investigate the role of defects in the contact region in order to explain the recently observed spectacular magnetoresistance ratio. Our results predict that possible presence of spin polarized
Ana Maria Rey, Keith Burnett, Robert Roth, Mark Edwards
We use the Bogoliubov theory of atoms in an optical lattice to study the approach to the Mott-insulator transition. We derive an explicit expression for the superfluid density based on the rigidity of the system under phase variations. This enables us to explore the connection between the quantum depletion of the condensate and the quasi-momentum distributio
Paul Romatschke
Using quasi-particle models, lattice data can be mapped to finite chemical potential. By comparing a simple and an HTL quasi-particle model, we derive the general trend that a full inclusion of the plasmon effect will give.
Damien Challet, Matteo Marsili
We discuss a simple model based on the Minority Game which reproduces the main stylized facts of anomalous fluctuations in finance. We present the analytic solution of the model in the thermodynamic limit and show that stylized facts arise only close to a line of critical points with non-trivial properties. By a simple argument, we show that, in Minority Gam
Robert Fleischer
After an introduction to the Standard-Model description of CP violation, we turn to the main focus of these lectures, the B-meson system. Since non-leptonic B decays play the key role for the exploration of CP violation, we have to discuss the tools to describe these transitions theoretically before classifying the main strategies to study CP violation. We w
Corner transfer matrix renormalization group method for two-dimensional self-avoiding walks and other O(n) models
cond-mat.stat-mechD. P. Foster, C. Pinettes
We present an extension of the corner transfer matrix renormalisation group (CTMRG) method to O(n) invariant models, with particular interest in the self-avoiding walk class of models (O(n=0)). The method is illustrated using an interacting self-avoiding walk model. Based on the efficiency and versatility when compared to other available numerical methods, w
G. Belanger, F. Boudjema, A. Pukhov, A. Semenov
The program micrOMEGAs that calculates the relic density of the lightest supersymmetric particle (LSP) in the MSSM is presented. The impact of coannihilation channels and of higher order corrections to Higgs widths is stressed. The dependence on the RGE code used to calculate the soft parameters is also discussed.
Jerzy Dydak
The paper contains an exposition of part of topology using partitions of unity. The main idea is to create variants of the Tietze Extension Theorem and use them to derive classical theorems. This idea leads to a new result generalizing major results on paracompactness (Stone Theorem and Tamano Theorem), a result which serves as a connection to Ascoli Theorem
L. Bussolari, P. Contucci, M. Degli Esposti, C. Giardina'
We perform a statistical analysis of deterministic energy-decreasing algorithms on mean-field spin models with complex energy landscape like the Sine model and the Sherrington Kirkpatrick model. We specifically address the following question: in the search of low energy configurations is it convenient (and in which sense) a quick decrease along the gradient
V. I. Abrosimov, A. Dellafiore, F. Matera
The effect of quadrupole-type surface vibrations on the quadrupole response function of heavy nuclei is studied by using a model based on the solution of the linearized Vlasov equation with moving-surface boundary conditions. By using a separable approximation for the residual interaction, an analytical expression is obtained for the moving-surface response
R. de la Madrid
We explicitly construct the Rigged Hilbert Space (RHS) of the free Hamiltonian $H_0$. The construction of the RHS of $H_0$ provides yet another opportunity to see that when continuous spectrum is present, the solutions of the Schrodinger equation lie in a RHS rather than just in a Hilbert space.
D. Guadagnoli, V. Lubicz, G. Martinelli, S. Simula
We present a strategy for a lattice evaluation of the neutron electric dipole moment induced by the strong CP violating term of the QCD Lagrangian. Our strategy is based on the standard definition of the electric dipole moment, involving the charge density operator J0, in case of three flavors with non-degenerate masses. We present a complete diagrammatic an
Heavy Residues with A<90 in the Asymmetric Reaction of 20 AMeV 124Sn+27Al as a Sensitive Probe of the Onset of Multifragmentation
nucl-exM. Veselsky, G. A. Souliotis, G. Chubarian, L. Trache
The cross sections and velocity distributions of heavy residues from the reaction of 20 AMeV 124Sn + 27Al have been measured at forward angles using the MARS recoil separator at Texas A&M in a wide mass range. A consistent overall description of the measured cross sections and velocity distributions was achieved using a model calculation employing the concep
Revised $α^4$ term of lepton $g-2$ from the Feynman diagrams containing an internal light-by-light scattering subdiagram
hep-phT. Kinoshita, M. Nio
The $α^4$ contribution to the lepton $g-2$ from a gauge-invariant set of 18 Feynman diagrams containing a light-by-light scattering subdiagram internally has been reevaluated by a method independent of the previous approach. Comparison of two methods revealed a program error in the first version. Correcting this error, the contributions of these 18 diagrams
Superconducting Double Transition and the Upper Critical Field Limit of Sr2RuO4 in Parallel Magnetic Fields
cond-mat.supr-conKazuhiko Deguchi, Makariy Tanatar, Zhiqiang Mao, Takehiko Ishiguro
We studied the specific heat and thermal conductivity of the spin-triplet superconductor Sr2RuO4 at low temperatures and under oriented magnetic fields H. We resolved a double peak structure of the superconducting transition under magnetic field for the first time, which provides thermodynamic evidence for the existence of multiple superconducting phases. We
S. Venturini, P. M. Solomon
We propose a new interpretation for the CO emitting region of the Cloverleaf (H1413+1143), a gravitationally lensed QSO. We fit a two-galaxy lensing model directly to the IRAM CO(7-6) data rather than to the optical HST image and from the fit we infer that the CO(7-6) source is a disk-like structure with a characteristic radius of $785 {\rm pc} (in the curre
A. J. Bracken
Classical mechanics is formulated in complex Hilbert space with the introduction of a commutative product of operators, an antisymmetric bracket, and a quasidensity operator. These are analogues of the star product, the Moyal bracket, and the Wigner function in the phase space formulation of quantum mechanics. Classical mechanics can now be viewed as a defor
Tiezheng Qian, Xiao-Ping Wang, Ping Sheng
From extensive molecular dynamics simulations on immiscible two-phase flows, we find the relative slipping between the fluids and the solid wall everywhere to follow the generalized Navier boundary condition, in which the amount of slipping is proportional to the sum of tangential viscous stress and the uncompensated Young stress. The latter arises from the
Volker D. Burkert
Recent results from JLab on the electromagnetic excitation of nucleon resonances are presented, and confronted with theoretical predictions. Preliminary data in the search for undiscovered states are discussed as well.
P. M. Visser, K. Allaart, D. Lenstra
We demonstrate how exactly bound cavity modes can be realized in dielectric structures other than 3d photonic crystals. For a microcavity consisting of crossed anisotropic layers, we derive the cavity resonance frequencies, and spontaneous emission rates. For a dielectric structure with dissipative loss and central layer with gain, the beta factor of direct
P. M. Visser, K. Allaart, D. Lenstra
We discuss level schemes of small quantum-dot turnstiles and their applicability in the production of entanglement in two-photon emission. Due to the large energy splitting of the single-electron levels, only one single electron level and one single hole level can be made resonant with the levels in the conduction band and valence band. This results in a mod
Heng Fan
The proof of additivity of entanglement of formation for some special cases is given. The strong concavity of von Neumann entropy due to strong subadditivity of von Neumann entropy is presented. Some general relations concerning about the entanglement of formation are proposed.
Heng Fan
The recent proposed realignment separability criterion for mixed is analyzed. We identify the essential part of this criterion is a swap operator followed by a partial transposition. Then we analyze the separability criterion of permutation indices of the density matrix for multipartite state which is a generalization of the realignment criterion. We give a
Yu-xi Liu, N. Imoto, S. K. Ozdemir, Guang-ri Jin
The non-resonant interaction between the high-density excitons in a quantum well and a single mode cavity field is investigated. An analytical expression for the physical spectrum of the excitons is obtained. The spectral properties of the excitons, which are initially prepared in the number states or the superposed states of the two different number states
Born--Infeld theory of electroweak and gravitational fields: Possible correction to Newton and Coulomb laws
quant-phDmitriy Palatnik
In this note one suggests a possibility of direct observation of the $θ$-parameter, introduced in the Born--Infeld theory of electroweak and gravitational fields, developed in quant-ph/0202024. Namely, one may treat $θ$ as a universal constant, responsible for correction to the Coulomb and Newton laws, allowing direct interaction between electrical charges a
Romeo Brunetti, Klaus Fredenhagen
We propose a general construction of an observable measuring the time of occurence of an effect in quantum theory. Time delay in potential scattering is computed as a straightforward application.
V. N. Solovov, F. Neves, V. Chepel, M. I. Lopes
A Large Area Avalanche Photodiode (LAAPD) was studied, aiming to access its performance as light detector at low temperatures, down to -80 C. The excess noise factor, F, was measured and found to be approximately independent of the temperature. A linear dependence of F on the APD gain with a slope of 0.00239 +/- 0.00008 was observed for gains above 100. The
Characteristic lengths at moving contact lines for a perfectly wetting fluid: the influence of speed on the dynamic contact angle
physics.flu-dynJens Eggers, Howard A. Stone
It is common to relate the dynamic contact angle $θ_d$ to the relative speed between the substrate and the contact line; theory suggests $θ_d^3 \propto U$. In fact, available physical models show that the dynamic angle involves speed logarithmically and in a model dependent manner. Experimental data consistent with this interpretation is cited.
R. Golub, W. M. Snow
There is a section in Chandrashekar's ''Newton's Principia for the Common Reader '', (Clarendon Press, Oxford, 1995) in which he claims to find a small error in the Principia. . However we believe that there is a mistake of interpretation underlying Chandra's claim and that the Principia is correct as it stands. This short paper d
On the short time prediction of earthquakes in the Balkan- Black Sea region based on geomagnetic field measurements and tide gravitational potential behavior
physics.geo-phS. Cht. Mavrodiev
The paper is a first attempt for statistical estimation of method for a short time prediction of incoming earthquake in the Balkan and Black Sea region from January to June, 2002. The essence of the discovery is that the geomagnetic local "quake" is a precursor of future earthquake, which time is determined by the tide gravitational potential behavio