February 2003 arXiv papers — page 3

Leonard Susskind

In this lecture I make some educated guesses, about the landscape of string theory vacua. Based on the recent work of a number of authors, it seems plausible that the lanscape is unimaginably large and diverse. Whether we like it or not, this is the kind of behavior that gives credence to the Anthropic Principle. I discuss the theoretical and conceptual issu

P. C. Schuster, R. L. Jaffe

Quantum particles confined to surfaces in higher dimensional spaces are acted upon by forces that exist only as a result of the surface geometry and the quantum mechanical nature of the system. The dynamics are particularly rich when confinement is implemented by forces that act normal to the surface. We review this confining potential formalism applied to t

B. Pioline

We point out the existence of a class of non-Gaussian yet free "quantum field theories" in 0+0 dimensions, based on a cubic action classified by simple Lie groups. A "three-pronged" version of the Wick theorem applies.

George Jorjadze, Gerhard Weigt

We quantise canonical free-field zero modes $p$, $q$ on a half-plane $p>0$ both, for the Liouville field theory and its reduced Liouville particle dynamics. We describe the particle dynamics in detail, calculate one-point functions of particle vertex operators, deduce their zero mode realisation on the half-plane, and prove that the particle vertex operators

Fu-Sin Ling, Pierre Ramond

We investigate symmetry breaking patterns from replicated gauge groups which generate anomaly-free and family-dependent U(1) symmetries. We discuss the extent to which these symmetries can explain the observed hierarchies of fermion masses and mixings.

D. Benson, I. I. Bigi, Th. Mannel, N. Uraltsev

We present a detailed evaluation of the total semileptonic B meson width in terms of |V_{cb}| and heavy quark parameters (quark masses and the expectation values of local heavy quark operators). Special attention is given to perturbative corrections which can precisely be calculated in a scheme with a hard Wilsonian cutoff at a scale around 1GeV appropriate

M. B. Voloshin

It is shown that the rates of the decays Upsilon(1^3D_1) -> eta Upsilon(1S) and Upsilon(1^3D_2) -> eta Upsilon(1S) should be comparable to and likely exceed that of the recently discussed in the literature two-pion transition Upsilon(1D) -> pi pi Upsilon(1S). The reason for this behavior is that the discussed eta transitions are enhanced by the contribution

Michael Gronau

While the Kobayashi--Maskawa single phase origin of CP violation passed its first crucial precision test in $B\to J/ψK_S$, the chirality of weak $b$-quark couplings has not yet been carefully tested. We discuss recent proposals for studying the chiral and CP-violating structure of these couplings in radiative and in hadronic B decays.

J. Fleischer, A. Leike, T. Riemann, A. Werthenbach

We present the complete electroweak one-loop corrections to top-pair production at a linear e^+e^- collider in the continuum region. Besides weak and photonic virtual corrections, real hard bremsstrahlung with simple realistic kinematical cuts is included. For the bremsstrahlung we advocate a semi-analytical approach with a high numerical accuracy. The virtu

R. Peschanski

String theory has long ago been initiated by the quest for a theoretical explanation of the observed high-energy ``Reggeization'' of strong interaction amplitudes. In terms of quantum field theory, it is the so-called ``soft'' regime, where the coupling constant is expected to be large and thus perturbative calculations inadequate. However, s

K. K. Szabo, A. I. Toth

We compare our 2+1 flavor, staggered QCD lattice results with a quasiparticle picture. We determine the pressure, the energy density, the baryon density, the speed of sound and the thermal masses as a function of T and $μ_B$. For the available thermodynamic quantities the difference is a few percent between the results of the two approaches. We also give the

M. Dubinin, H. J. Schreiber, A. Vologdin

We examine the prospects for measuring the $H Z γ$ coupling of a Standard Model-like Higgs boson with a mass between 120 and 160 GeV at the future TESLA linear \ee collider, assuming an integrated luminosity of 1 ab$^{-1}$ and a center-of-mass energy of 500 GeV. We consider the Higgs boson produced in association with $ν_e \bar{ν_e}$ via the $W W$ fusion rea

Josip Trampetic

In these lectures I first cover radiative and semileptonic B decays, including the QCD corrections for the quark subprocesses. The exclusive modes and the evaluation of the hadronic matrix elements, i.e. the relevant hadronic form factors, are the second step. Small effects due to the long-distance, spectator contributions, etc. are discussed next. The secon

K. Holland, P. Minkowski, M. Pepe, U. -J. Wiese

We study theories with the exceptional gauge group G(2). The 14 adjoint "gluons" of a G(2) gauge theory transform as {3}, {3bar} and {8} under the subgroup SU(3), and hence have the color quantum numbers of ordinary quarks, anti-quarks and gluons in QCD. Since G(2) has a trivial center, a "quark" in the {7} representation of G(2) can be scree

F. Muheim

The 64-channel Multianode Photo Multiplier (MaPMT) has been evaluated as a candidate for the LHCb Ring Imaging Cherenkov (RICH) photo detectors. We present result from data taken with a 3x3 array of closely packed MaPMTs mounted onto the RICH 1 prototype vessel, exposed to charged particle beams at CERN, and read out at LHC speed. Using a LED light source, w

Gilad Gour

It was shown in a previous work that, for systems in which the entropy is an extensive function of the energy and volume, the Bekenstein and the holographic entropy bounds predict new results. In this paper, we go further and derive improved upper bounds to the entropy of {\it extensive} charged and rotating systems. Furthermore, it is shown that for charged

G. M. Shore

The causal properties of curved spacetime, which underpin our sense of time in gravitational theories, are defined by the null cones of the spacetime metric. In classical general relativity, it is assumed that these coincide with the light cones determined by the physical propagation of light rays. However, the quantum vacuum acts as a dispersive medium for

R. Meinel, G. Neugebauer

It is shown that the class of asymptotically flat solutions to the axisymmetric and stationary vacuum Einstein equations with reflection symmetry of the metric is uniquely characterized by a simple relation for the Ernst potential on the upper part of the symmetry axis. This result generalizes a well-known fact from potential theory.

N. Pinto-Neto, E. Sergio Santini

We study the quantized Friedmann-Lema\^ıtre-Robertson-Walker (FLRW) model minimally coupled to a free massless scalar field. In a previous paper, \cite{fab2}, solutions of this model were constructed as gaussian superpositions of negative and positive modes solutions of the Wheeler-DeWitt equation, and quantum bohmian trajectories were obtained in the framew

Domenico Giulini

This is an introduction into the problem of how to set up black hole initial-data for the matter-free field equations of General Relativity. The approach is semi-pedagogical and addresses a more general audience of astrophysicists and students with no specialized training in General Relativity beyond that of an introductory lecture.

Hanno Sahlmann, Thomas Thiemann

Much of the work in loop quantum gravity and quantum geometry rests on a mathematically rigorous integration theory on spaces of distributional connections. Most notably, a diffeomorphism invariant representation of the algebra of basic observables of the theory, the Ashtekar-Lewandowski representation, has been constructed. This representation is singled ou

S. Bekhechi, B. W. Southern

Violation of the fluctuation-dissipation theorem (FDT) in a frustrated Heisenberg model on the Kagome lattice is investigated using Monte Carlo simulations. The model exhibits glassy behaviour at low temperatures accompanied by very slow dynamics. Both the spin-spin autocorrelation function and the response to an external magnetic field are studied. Clear ev

F. Q. Potiguar, U. M. S. Costa

We use a scheme of separation of degrees of freedom for a system, in order to produce two systems with finite number of degrees of freedom. Our intent is to measure the energy square relative fluctuation (SRF) of the observable part through the simulation of two simple examples of composed systems, the harmonic oscillator, and the chain of quartic oscillator

A. Zheludev, T. Sato, T. Masuda, K. Uchinokura

The square-lattice antiferromagnet Ba2CoGe2O7 is studied by means of neutron diffraction and inelastic scattering. This material is isostructural to the well-known Dzyaloshinskii-Moriya helimagnet Ba2CuGe2O7, but exhibits commensurate long-range Neel order at low temperatures. Measurements of the spin wave dispersion relation reveal strong in-plane anisotrop

I. Ispolatov, M. Karttunen

Collapse and reverse to collapse explosion transition in self-gravitating systems are studied by molecular dynamics simulations. A microcanonical ensemble of point particles confined to a spherical box is considered; the particles interact via an attractive soft Coulomb potential. It is observed that the collapse in the particle system indeed takes place whe

D. P. Varn, G. S. Canright, J. P. Crutchfield

In the previous paper of this series [D. P. Varn, G. S. Canright, and J. P. Crutchfield, Physical Review B, submitted] we detailed a procedure--epsilon-machine spectral reconstruction--to discover and analyze patterns and disorder in close-packed structures as revealed in x-ray diffraction spectra. We argued that this computational mechanics approach is more

M. Moskalets, M. Buttiker

Time periodic perturbations of an electron system on a ring are examined. For small frequencies periodic small amplitude perturbations give rise to side band currents which in leading order are inversely proportional to the frequency. These side band currents compensate the current of the central band such that to leading order no net pumped current is gener

D. P. Varn, G. S. Canright, J. P. Crutchfield

In a recent publication [D. P. Varn, G. S. Canright, and J. P. Crutchfield, Phys. Rev. B {\bf 66}:17, 156 (2002)] we introduced a new technique for discovering and describing planar disorder in close-packed structures (CPSs) directly from their diffraction spectra. Here we provide the theoretical development behind those results, adapting computational mecha

Scott A. Hill, Gene F. Mazenko

We examine the hydrodynamics of a granular gas using numerical simulation. We demonstrate the appearance of shearing and clustering instabilities predicted by linear stability analysis, and show that their appearance is directly related to the inelasticity of collisions in the material. We discuss the rate at which these instabilities arise and the manner in

G. Misguich, B. Bernu, L. Pierre

We present a high-temperature expansion (HTE) of the magnetic susceptibility and specific heat data of Melzi et al. on Li2VOSiO4 [Phys. Rev. B 64, 024409 (2001)]. The data are very well reproduced by the J1-J2 Heisenberg model on the square lattice with exchange energies J1=1.25+-0.5 K and J2=5.95+-0.2 K. The maximum of the specific heat Cv^{max}(T_{max}) is

Dimitrios Geromichalos, Mika M. Kohonen, Frieder Mugele, Stephan Herminghaus

We have studied the effect of small amounts of added liquid on the dynamic behavior of a granular system consisting of a mixture of glass beads of two different sizes. Segregation of the large beads to the top of the sample is found to depend in a nontrivial way on the liquid content. A transition to viscoplastic behavior occurs at a critical liquid content,

G. Ovarlez, E. Clément

We present experimental results on slow flow properties of a granular assembly confined in a vertical column and driven upwards at a constant velocity V. For monodisperse assemblies this study evidences at low velocities ($1<V<100 μm/s$) a stiffening behaviour i.e. the stress necessary to obtain a steady sate velocity increases roughly logarithmically with v

M. Titov, H. Schomerus

Within a general framework, we discuss the wave function statistics in the Lloyd model of Anderson localization on a one-dimensional lattice with a Cauchy distribution for the random on-site potential. We demonstrate that already in leading order in the disorder strength, there exists a hierarchy of anomalies in the probability distributions of the wave func

Raymond J. Hawkins, B. Roy Frieden

We present a novel synthesis of Fisher information and asset pricing theory that yields a practical method for reconstructing the probability density implicit in security prices. The Fisher information approach to these inverse problems transforms the search for a probability density into the solution of a differential equation for which a substantial collec

B. Meyer

Using density-functional theory in combination with a thermodynamic formalism we calculate the relative stability of various structural models of the polar O-terminated (000-1)-O surface of ZnO. Model surfaces with different concentrations of oxygen vacancies and hydrogen adatoms are considered. Assuming that the surfaces are in thermodynamic equilibrium wit

P. J. H. Denteneer, R. T. Scalettar

The effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the Determinant Quantum Monte Carlo method, the temperature- and magnetic-field- dependent conductivity is calculated,as well as the degree of spin polarization. We find that the Zeeman magnetic field suppr

Horacio S. Wio, Raul Toral

Here we study a noise induced transition when the system is driven by a noise source taken as colored and non-Gaussian. We show--using both, a theoretical approximation and numerical simulations-- that there is a shift of the transition as the noise departs from the Gaussian behavior. Also, we confirm the reentrance effect found for colored Gaussian noise an

A. V. Sologubenko, H. R. Ott, G. Dhalenne, A. Revcolevschi

The thermal conductivity of the spin-1/2 chain cuprate BaCu2Si2O7 was measured along different crystallographic directions in the temperature region between 0.5 and 300 K. The thermal conductivity along the chain direction considerably exceeds that along perpendicular directions. Near the antiferromagnetic transition at T_N = 9.2 K the data indicates enhance

Mehmet Dilaver, Semra Gündüç, Meral Aydın, Yiğit Gündüç

In this work we have considered the Taylor series expansion of the dynamic scaling relation of the magnetization with respect to small initial magnetization values in order to study the dynamic scaling behaviour of 2- and 3-dimensional Ising models. We have used the literature values of the critical exponents and of the new dynamic exponent $x_0$ to observe

Macleans L. Ndawana, V. E. Kravtsov

We study level statistics of a critical random matrix ensemble of a power-law banded complex Hermitean matrices. We compute numerically the level compressibility via the level number variance and compare it with the analytical formula for the exactly solvable model of Moshe, Neuberger and Shapiro.

J. E. Lye, J. J. Hope, J. D. Close

We propose and analyze a series of non-destructive, dynamic detectors for Bose-Einstein condensates based on photo-detectors operating at the shot noise limit. These detectors are compatible with real time feedback to the condensate. The signal to noise ratio of different detection schemes are compared subject to the constraint of minimal heating due to phot

Kazumitsu Sakai, Masahiro Shiroishi, Yoshihiro Nishiyama, Minoru Takahashi

We exactly evaluate the third neighbor correlator <S_j^z S_{j+3}^z> and all the possible non-zero correlators <S^{alpha}_j S^{beta}_{j+1} S^{gamma}_{j+2} S^{delta}_{j+3}> of the spin-1/2 Heisenberg $XXX$ antiferromagnet in the ground state without magnetic field. All the correlators are expressed in terms of certain combinations of logarithm ln2, the Riemann

Satoshi Fujimoto

We investigate a (semi-)metal to insulator transition (MIT) realized in geometrically frustrated electron systems on the basis of the Hubbard model on a three-dimensional pyrochlore lattice and a two-dimensional checkerboard lattice. Using the renormalization group method and mean field analysis, we show that in the half-filling case, MIT occurs as a result

Maciej M. Maska, Marcin Mierzejewski

We investigate the vortex structure assuming the d-density wave scenario of the pseudogap. We discuss the profiles of the order parameters in the vicinity of the vortex, effective vortex charge and the local density of states. We find a pronounced modification of these quantities when compared to a purely superconducting case. Results have been obtained for

Oron Zachar

Spontaneous bond dimerization (BD) was cojectured to be central to the physics of the cuperate superconductors. Based on ladder models and numerical simulations, we examine the quantitative issue of whether the energy scales involved are sufficient to influence the mechanisms of pairing, stripe formation, pseudo-gap, and quantum critical `normal&#39; state p

S. V. Kozyrev

The alternative to the replica procedure, which we call the noncommutative replica procedure, is discussed. The detailed comparison with the standard replica procedure is performed.

U. Tirnakli, M. L. Lyra

The short-time and long-time dynamics of the Bak-Sneppen model of biological evolution are investigated using the damage spreading technique. By defining a proper Hamming distance measure, we are able to make it exhibits an initial power-law growth which, for finite size systems, is followed by a decay towards equilibrium. In this sense, the dynamics of self

B. C. Dunne, Y. -H. Chu, C. -H. R. Chen, J. D. Lowry

The emission nebula M17 contains a young ~1 Myr-old open cluster; the winds from the OB stars of this cluster have blown a superbubble around the cluster. ROSAT observations of M17 detected diffuse X-ray emission peaking at the cluster and filling the superbubble interior. The young age of the cluster suggests that no supernovae have yet occurred in M17; the

Eduardo Gueron, Patricio S. Letelier

We present a novel method to study interacting orbits in a fixed mean gravitational field associated with a solution of the Einstein field equations. The idea is to consider the Newton gravity among the orbiting particles in a geometry given by the main source. We apply the technique in the of study two and three self-gravitating particles moving around a bl

M. Cervino, V. Luridiana

In this contribution we evaluate the minimal cluster mass for which the effects of an incomplete sampling of the Initial Mass Function (IMF) cannot be neglected. This minimal cluster mass corresponds to the situation in which the integrated luminosity of the cluster modeled equals the luminosity of the most luminous individual star included in the model, and

Yoshiaki Hagiwara, Philip J. Diamond, Makoto Miyoshi

We performed VLA observations of the 22 GHz H2O maser emission in the merging galaxy NGC6240, which hosts the well-known double active nuclei. In a previous paper, we reported on the first solid detection of the H2O maser emission in 2001. After two abortive attempts due to the weakness and probable variability of the emission, the maser was detected with th

L. Tornatore, S. Borgani, V. Springel, F. Matteucci

We discuss Tree+SPH simulations of galaxy clusters and groups, aimed at studying the effect of cooling and non-gravitational heating on observable properties of the ICM. We simulate at high resolution four halos,with masses in the range (0.2-4)10^{14}M_sol. We discuss the effects of using different SPH implementations and show that high resolution is mandato

Guenther Hasinger, the CDF-S team

Deep X-ray surveys have shown that the cosmic X-ray background (XRB) is largely due to the accretion onto supermassive black holes, integrated over the cosmic time. These surveys have resolved more than 80% of the 0.1-10 keV X-ray background into discrete sources. Optical spectroscopic identifications show that the sources producing the bulk of the X-ray bac

Pinaki Chatterjee, Lars Hernquist, Abraham Loeb

We examine whether massive binary black holes in spherically symmetric bulges of galaxies can achieve coalescence through the emission of gravitational radiation under the action of stellar dynamical processes alone. In particular, we address the importance of the Brownian motion of a binary&#39;s center-of-mass to its continued interaction with stellar orbi

J. Kuraszkiewicz, B. J. Wilkes, E. J. Hooper, K. Wood

[Abridged] We present ISO far-infrared (IR) observations of 21 hard X-ray selected AGN from the HEAO-1 A2 sample. We compare the far-IR to X-ray spectral energy distributions (SEDs) of this sample with various radio and optically selected AGN samples. The hard-X-ray selected sample shows a wider range of optical/UV shapes extending to redder near-IR colors.

B. Stelzer, V. Burwitz

We present a simultaneous Chandra and XMM-Newton observation of the Castor sextett, focusing on Castor A and Castor B, two spectroscopic binaries with early-type primaries. Of the present day X-ray instruments only Chandra can isolate the X-ray lightcurves and spectra of A and B. We compare the Chandra observation with XMM-Newton data obtained simultaneously

H. W. W. Spoon, A. F. M. Moorwood, K. M. Pontoppidan, J. Cami

The composition of ice grains provides an important tool for the study of the molecular environment of star forming regions. Using ISAAC at the VLT to obtain spectra around 4.65 microns we have detected for the first time `XCN&#39; and CO ice in an extragalactic environment: the nuclear region of the nearby dusty starburst/AGN galaxy NGC4945. The profile of

Fabio Favata, Giuseppina Micela

Coronal astronomy is by now a fairly mature discipline, with a quarter century having gone by since the detection of the first stellar X-ray coronal source (Capella), and having benefitted from a series of major orbiting observing facilities. Several observational characteristics of coronal X-ray and EUV emission have been solidly established through extensi

Jennifer Hatchell

Observations of low mass protostars which probe small enough size scales to be within likely CO depletion regions show the highest [NH2D]/[NH3] ratios yet measured, of 4--33%. These molecular D/H ratios are higher than those measured on larger scales, showing that deuterium fractionation increases towards protostellar cores. As in cold clouds, such high rati

D. Maino, C. Burigana, F. Pasian

In this paper we discuss the issue of loosing telemetry (TM) data due to different reasons (e.g. spacecraft-ground transmissions) while performing a full-sky survey with space-borne instrumentation. This is a particularly important issue considering the current and future space missions (like Planck from ESA and WMAP from NASA) operating from an orbit far fr

G. Tovmassian, S. Zharikov, R. Michel, ; V. Neustroev

FS Aur is a known dwarf nova with an orbital period of about 85.7 minutes. It has been assumed to be a member of the SU UMa subclass of cataclysmic variables (CVs), but previous searches for superhumps and superoutburst have been unsuccessful. We conducted a series of photometric and spectroscopic observations of FS Aur during quiescence. We confirmed its sh

Raul Jimenez, Licia Verde, Tommaso Treu, Daniel Stern

We place tight constraints on the redshift-averaged, effective value of the equation of state of dark energy, w, using only the absolute ages of Galactic stars and the observed position of the first peak in the angular power spectrum of the CMB. We find w<-0.8 at the 68% confidence level. If we further consider that w > -1, this finding suggests that within

Jiri Vanicek, Eric J. Heller

We present a numerically feasible semiclassical (SC) method to evaluate quantum fidelity decay (Loschmidt echo, FD) in a classically chaotic system. It was thought that such evaluation would be intractable, but instead we show that a uniform SC expression not only is tractable but it gives remarkably accurate numerical results for the standard map in both th

S. I. Kruglov

Dynamical symmetry breaking and the formation of scalar condensates in the SU(2)XU(1) Nambu-Jona-Lasinio model with two coupling constants has been studied in the framework of the mean field approximation. The bosonization procedures of the model are performed using the functional integration method. The possibility of the spontaneous CP symmetry breaking in

Pasha Zusmanovich

We obtain formulas for the first and second cohomology groups of a general current Lie algebra with coefficients in the &#34;current&#34; module, and apply them to compute structure functions for manifolds of loops with values in compact Hermitian symmetric spaces.

Oscar Rosas-Ortiz, Rodrigo Munoz

It is shown that the radial part of the Hydrogen Hamiltonian factorizes as the product of two not mutually adjoint first order differential operators plus a complex constant epsilon. The 1-susy approach is used to construct non-hermitian Hamiltonians with hydrogen spectra. Other non-hermitian Hamiltonians are shown to admit an extra `complex energy&#39; at e

A. Carpio, L. L. Bonilla

The static stress needed to depin a 2D edge dislocation, the lower dynamic stress needed to keep it moving, its velocity and displacement vector profile are calculated from first principles. We use a simplified discrete model whose far field distortion tensor decays algebraically with distance as in the usual elasticity. An analytical description of dislocat

D. Dalmazi, A. de Souza Dutra, Marcelo Hott

Here we address the problem of bosonizing massive fermions without making expansions in the fermion masses in both massive $QED_2$ and $QED_3$ with $ N $ fermion flavors including also a Thirring coupling. We start from two point correlators involving the U(1) fermionic current and the gauge field. From the tensor structure of those correlators we prove that

Eduard Massó, Francesc Rota

In the standard hot big bang model, the expansion of the early universe is given by the Friedmann equation with an energy density dominated by relativistic particles. Since in a variety of models this equation is altered, we introduce modifications in the Friedmann equation and show that we can constrain them using big bang nucleosynthesis data. When there i

Eugenio R. Bezerra de Mello, Yves Brihaye, Betti Hartmann

We study both global as well as local (Nielsen-Olesen) strings in de Sitter space. While these type of topological defects have been studied in the background of a de Sitter metric previously, we study here the full set of coupled equations. We find only ``closed&#39;&#39; solutions. The behaviour of the metric tensor of these solutions resembles that of ``s

Sabine Hossenfelder, Marcus Bleicher, Stefan Hofmann, Horst Stöcker

Recent calculations applying statistical mechanics indicate that in a setting with compactified large extra dimensions a black hole might evolve into a (quasi-)stable state with mass close to the new fundamental scale $M_f$. Black holes and therefore their relics might be produced at the LHC in the case of extra-dimensional topologies. In this energy regime,

Giacomo Cacciapaglia, Marco Cirelli, Andrea Romanino

We consider the mixing of muon and tau neutrinos with sterile fermion fields propagating in extra dimensions in the context of core collapse supernova physics, extending the analysis of the electron neutrino case done in a previous work. We show that the potentially dramatic modifications to the supernova evolution are prevented by a mechanism of feedback, s

Leszek Hadasz, Zbigniew Jaskolski

The applications of the existing Liouville theories for the description of the longitudinal dynamics of non-critical Nambu-Goto string are analyzed. We show that the recently developed DOZZ solution to the Liouville theory leads to the cut singularities in tree string amplitudes. We propose a new version of the Polyakov geometric approach to Liouville theory

Manuel Drees, Michael Rauch

We investigate the violation of time reversal invariance in the decay of the free neutron in the framework of the Minimal Supersymmetric Standard Model (MSSM). The coefficient of the triple product of the neutron spin and the momenta of electron and neutrino, the so called D parameter, is computed at one loop order including all diagrams. We find that D is m

I. Tifrea, D. Bodea, I. Grosu, M. Crisan

We consider the fluctuation conductivity in the critical region of a disorder induced quantum phase transition in layered d-wave superconductors. We specifically address the fluctuation contribution to the system&#39;s conductivity in the limit of large (quasi-two-dimensional system) and small (quasi-three-dimensional system) separation between adjacent laye

Abhijit Bandyopadhyay, Sandhya Choubey, Srubabati Goswami

However the allowed range of $θ_{\odot}$ ($θ_{12}$) did not change much with the inclusion of the KamLAND results. In this paper we probe if future data from KamLAND can increase the accuracy of the allowed range in $θ_{\odot}$ and conclude that even after 3 kton-year of statistics and most optimistic error estimates, KamLAND {\it may} find it hard to signif

Hsiao-Ping Hsu, Vishal Mehra, Peter Grassberger

We study an off-lattice protein toy model with two species of monomers interacting through modified Lennard-Jones interactions. Low energy configurations are optimized using the pruned-enriched-Rosenbluth method (PERM), hitherto employed to native state searches only for off lattice models. For 2 dimensions we found states with lower energy than previously p

Michael Hewitt

A family of superpotentials is constructed which may be relevant to supersymmetry breaking in 4 dimensional (0,1) heterotic string models. The scale of supersymmetry breaking, as well as the coupling constant, would be stable.

R. Ruffini, L. Vitagliano, S. -S. Xue

We describe the creation and evolution of electron-positron pairs in a strong electric field as well as the pairs annihilation into photons. The formalism is based on generalized Vlasov equations, which are numerically integrated. We recover previous results about the oscillations of the charges, discuss the electric field screening and the relaxation of the

S. A. Zvyagin, J. Krzystek, P. H. M. van Loosdrecht, G. Dhalenne

The dimerized-incommensurate phase transition in the spin-Peierls compound CuGeO$_3$ is probed using multifrequency high-resolution electron spin resonance (ESR) technique, in magnetic fields up to 17 T. A field-induced development of the soliton-like incommensurate superstructure is clearly indicated as a pronounced increase of the ESR linewidth $ΔB$ (magno

S. R. Gevorkyan, E. A. Kuraev

The problem of summation of the perturbation series for the process of lepton pair production in relativistic ion collisions is investigated. We show that the amplitude of this process can be obtained in the compact analytical form, if one confines to the terms growing as a powers of logarithm energy in the cross section, the approximation of which is comple

A. T. Burkov, A. Yu. Zyuzin, T. Nakama, K. Yagasaki

New mechanism of magnetoresistivity in itinerant metamagnets with a structural disorder is introduced basing on analysis of experimental results on magnetoresistivity, susceptibility, and magnetization of structurally disordered alloys (Y$_{1-x}$Gd$_{x}$)Co$_{2}$. In this series, YCo$_{2}$ is an enhanced Pauli paramagnet, whereas GdCo$_{2}$ is a ferrimagnet

Attilio Cucchieri, Tereza Mendes, Andre Taurines

We present a numerical study of the gluon propagator in lattice Landau gauge for three-dimensional pure-SU(2) lattice gauge theory at couplings beta = 4.2, 5.0, 6.0 and for lattice volumes V = 40^3, 80^3, 140^3. In the limit of large V we observe a decreasing gluon propagator for momenta smaller than p_{dec} = 350^{+ 100}_{- 50} MeV. Data are well fitted by

Eric F. Bell, Daniel H. McIntosh, Neal Katz, Martin D. Weinberg

We use a large sample of galaxies from the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to calculate galaxy luminosity and stellar mass functions in the local Universe. We estimate k-corrections, evolution corrections, and stellar mass-to-light ratios (M/Ls) by fitting the galaxy colors with simple models. Our optical and near-in

A. Crisanti, T. Rizzo, T. Temesvari

We consider the spin-glass phase of the Sherrington-Kirkpatrick model in the presence of a magnetic field. The series expansion of the Parisi function $q(x)$ is computed at high orders in powers of $τ=T_c-T$ and $H$. We find that none of the Parisi-Toulouse scaling hypotheses on the $q(x)$ behavior strictly holds, although some of them are violated only at h

Kunihito Ioka, Misao Sasaki

A formulation is developed for general relativistic ideal magnetohydrodynamics in stationary axisymmetric spacetimes. We reduce basic equations to a single second-order partial differential equation, the so-called Grad-Shafranov (GS) equation. Our formulation is most general in the sense that it is applicable even when a stationary axisymmetric spacetime is

Y. Fuseya, H. Kohno, K. Miyake

A possibility of the realization of the p-wave spin-singlet superconductivity ($p$SS), whose gap function is odd both in momentum and in frequency, is investigated by solving the gap equation with the phenomenological interaction mediated by the antiferromagnetic spin fluctuation. The $p$SS is realized prevailing over the d-wave singlet superconductivity ($d

D. Brecher, P. M. Saffin

Just as the single fluxbrane is quantum mechanically unstable to the nucleation of a locally charged spherical brane, so intersecting fluxbranes are unstable to various decay modes. Each individual element of the intersection can decay via the nucleation of a spherical brane, but uncharged spheres can also be nucleated in the region of intersection. For spec

S. M. Kuzenko, I. N. McArthur

There are currently many string inspired conjectures about the structure of the low-energy effective action for super Yang-Mills theories which require explicit multi-loop calculations. In this paper, we develop a manifestly covariant derivative expansion of superspace heat kernels and present a scheme to evaluate multi-loop contributions to the effective ac

Marion Scheepers, Boaz Tsaban

In this paper we extend previous studies of selection principles for families of open covers of sets of real numbers to also include families of countable Borel covers. The main results of the paper could be summarized as follows: 1. Some of the classes which were different for open covers are equal for Borel covers -- Section 1; 2. Some Borel classes coinci

D. B. Leinweber, A. W. Thomas, R. D. Young

We demonstrate that the extremely accurate lattice QCD data for the mass of the nucleon recently obtained by CP-PACS, combined with modern chiral extrapolation techniques, leads to a value for the mass of the physical nucleon which has a systematic error of less than one percent.

K. A. Samani, F. Loran

Using the method of shape invariant potentials, a number of exact solutions of one dimensional effective mass Schrodinger equation are obtained. The solutions with equi-spaced spectrum are discussed in detail.

B. Navarro, I. L. Egusquiza, J. G. Muga, G. C. Hegerfeldt

The well-known laser-induced Rabi oscillations of a two-level atom are shown to be suppressed under certain conditions when the atom is entering a laser-illuminated region. For temporal Rabi oscillations the effect has two regimes: classical-like, at intermediate atomic velocities, and quantum at low velocities, associated respectively with the formation of

G. Cassinelli, E. De Vito, A. Toigo

Given an irreducible representation of a group G, we show that all the covariant positive operator valued measures based on G/Z, where Z is a central subgroup, are described by trace class, trace one positive operators.

Viatcheslav Kokoouline, Robin Santra, Chris H. Greene

We present a multichannel scattering calculation of elastic and inelastic cold collisions between two low-field seeking, metastable ^{88}Sr [(5s5p) ^3P_2] atoms in the presence of an external magnetic field. The scattering physics is governed by strong anisotropic long-range interactions, which lead to pronounced coupling among the partial waves of relative

J. A. Lipa, J. A. Nissen, S. Wang, D. A. Stricker

We describe the results of an experiment to test for spacetime anisotropy terms that might exist from Lorentz violations. The apparatus consists of a pair of cylindrical superconducting cavity-stabilized oscillators operating in the TM_{010} mode with one axis east-west and the other vertical. Spatial anisotropy is detected by monitoring the beat frequency a

P. Schuck, H. Horiuchi, G. Röpke, A. Tohsaki

A round up of the present status of the conjecture that n alpha nuclei form an alpha-particle condensate in excited states close to the n alpha threshold is given. Experiments which could demonstrate the condensate character are proposed. Possible lines of further theoretical developments are discussed.

K. -H. Chiam, M. -C. Lai, H. S. Greenside

An efficient semi-implicit second-order-accurate finite-difference method is described for studying incompressible Rayleigh-Benard convection in a box, with sidewalls that are periodic, thermally insulated, or thermally conducting. Operator-splitting and a projection method reduce the algorithm at each time step to the solution of four Helmholtz equations an

Hasan R. Karadayi, Meltem Gungormez

With the introduction of special roots, we show the existence of some special weights with quite interesting properties for finite Lie algebras. We propose and discuss two statements which lead us to an explicit construction of these special weights and roots. It is seen that special weights provides us an alternative way of expressing the whole action of We

Dennis Sullivan

There is an interpretation of open string field theory in algebraic topology. An interpretation of closed string field theory can be deduced from this open string theory to obtain as well the interpretation of open and closed string field theory combined.