October 2003 arXiv papers — page 3

Eric Akkermans, Sankalpa Ghosh

We study the vortex nucleation in a finite Bose-Einstein condensate. Using a set of non-local and chiral boundary conditions to solve the Schr$\ddot{o}$dinger equation of non-interacting bosons in a rotating trap, we obtain a quantitative expression for the characteristic angular velocity for vortex nucleation in a condensate which is found to be 35% of the

Kazuki Hasebe, Yusuke Kimura

We construct higher dimensional quantum Hall systems based on fuzzy spheres. It is shown that fuzzy spheres are realized as spheres in colored monopole backgrounds. The space noncommutativity is related to higher spins which is originated from the internal structure of fuzzy spheres. In $2k$-dimensional quantum Hall systems, Laughlin-like wave function suppo

Leor Barack, Curt Cutler

Captures of stellar-mass compact objects (COs) by massive ($\sim 10^6 M_\odot$) black holes (MBHs) are potentially an important source for LISA, the proposed space-based gravitational-wave (GW) detector. The orbits of the inspiraling COs are highly complicated; they can remain rather eccentric up until the final plunge, and display extreme versions of relati

Bart D'Hooghe

It is generally accepted that no `faster than light signalling' (FTLS) using two entangled spin 1/2 particles is possible because of indeterminism in a quantum measurement and linearity of standard quantum mechanics. We show how in principle one bit of information could be transmitted using local measurements and a global unitary transformation of the st

Daryl Achilles, Christine Silberhorn, Cezary Sliwa, Konrad Banaszek

Detectors that can resolve photon number are needed in many quantum information technologies. In order to be useful in quantum information processing, such detectors should be simple, easy to use, and be scalable to resolve any number of photons, as the application may require great portability such as in quantum cryptography. Here we describe the constructi

Antonio Di Lisi, Silvio De Siena, Fabrizio Illuminati

We investigate the effects of spontaneous scattering on the evolution of entanglement of two atomic samples, probed by phase shift measurements on optical beams interacting with both samples. We develop a formalism of conditional quantum evolutions and present a wave function analysis implemented in numerical simulations of the state vector dynamics. This me

Lajos Diosi

The theory of decoherent histories is checked for the requirement of statistical independence of subsystems. Strikingly, this is satisfied only when the decoherence functional is diagonal in both its real a n d imaginary parts. In particular, the condition of consistency (or weak decoherence) required for the assignment of probabilities appears to be ruled o

Franz Embacher, Heide Narnhofer

We consider the problem of determining the mixed quantum state of a large but finite number of identically prepared quantum systems from data obtained in a sequence of ideal (von Neumann) measurements, each performed on an individual copy of the system. In contrast to previous approaches, we do not average over the possible unknown states but work out a ``ty

Jian Qi Shen

By making use of the Lewis-Riesenfeld invariant theory, the solution of the Schrödinger equation for the time-dependent linear potential corresponding to the quadratic-form Lewis-Riesenfeld invariant $I_{\rm q}(t)$ is obtained in the present paper. It is emphasized that in order to obtain the general solutions of the time-dependent Schrödinger equation, one

Wang Yongzhong

The unjustifiable or wrong in the previous magnetism theories has been indicated in this paper. For a N electrons system with Heisenberg exchange integral, the correct exchange Hamilton should be of two terms, not only one as in the previous magnetism theories. The role of the minor term in the exchange Hamilton was considered. Based on the principle of supe

L. Zhou, X. X. Yi, H. S. Song, Y. Q. Quo

The thermal entanglement of two spin-1 atoms with nonlinear couplings in optical lattices is investigated in this paper. It is found that the nonlinear couplings favor the thermal entanglement creating. The dependence of the thermal entanglement in this system on the linear coupling, the nonlinear coupling, the magnetic field and temperature is also presente

H. Fearn, R. H. Gibb

In this paper we show that if the refractive index, or rather (n(w) -1) satisfies the dispersion relations then, it is implied by Titchmarsh's theorem that n(w) -> 1 as w -> infinity. Any other limiting value for n(w) would violate relativistic causality, by which we mean not only that cause must precede effect but also that signals cannot travel faster-

Joao Magueijo

We propose that the evolutionary purpose of junk DNA is to protect the gene. Mutation agents, such as retro-viruses, hit ``decoy'' DNA most of the time. Although the argument is far from general, we propose that the percentage of junk DNA should correlate with the number of retroviruses attacking a given species. It should also anti-correlate with th

Mark Ya. Azbel'

Mortality is an instrument of natural selection. Evolutionary motivated theories imply its irreversibility and life history dependence. This is inconsistent with mortality data for protected populations. Accurate analysis yields mortality law, which is specific for their evolutionary unprecedented conditions, yet universal for species as evolutionary remote

Rodrick Wallace, Deborah Wallace

We expand the current understanding of ecological resilience to include the nested hierarchy of cognitive submodules that particularly, if not uniquely, delineates human ecosystems. These modules, ranging from the immune system to the local social network, are embedded in a cultural milieu which, to take the perspective of the evolutionary anthropologist Rob

Shyamal Sengupta

This is a lecture on the ethics and role of science in promoting rational and objective thinking in society. It was delivered by Prof. Shyamal Sengupta of Kolkata, India. Prof. Sengupta, who passed away recently, has inspired generations of Indian physicists by his rational viewpoints on science and by teaching his students the importance of a scientific out

E. P. Bonvin, S. T. Hatamian

An economical procedure to upgrade the existing Fairport water Cherenkoff detector is described. The detector will lower its energy threshold by increased photocoverage and light yield. Furthermore, by addition of a Gd salt it will become sensitive to neutrons produced by the inverse beta decay of anti-neutrinos on protons. The new detector can then take adv

M. Waechter, F. Riess, H. Kantz, J. Peinke

For the characterization of surface height profiles we present a new stochastic approach which is based on the theory of Markov processes. With this analysis we achieve a characterization of the complexity of the surface roughness by means of a Fokker-Planck or Langevin equation, providing the complete stochastic information of multiscale joint probabilities

Susan B. Rempe, D. Asthagiri, Lawrence R. Pratt

K+(aq) ion is an integral component of many cellular processes, amongst which the most important, perhaps, is its role in transmitting electrical impulses along the nerve. Understanding its hydration structure and thermodynamics is crucial in dissecting its role in such processes. Her we address these questions using both the statistical mechanical quasi-che

K. Goulianos, M. Gallinaro, K. Hatakeyama, S. Lami

Two MiniPlug calorimeters, designed to measure the energy and lateral position of particles in the pseudorapidity region of 3.6<|eta|<5.1 of the CDF detector, have been installed as part of the Run II CDF upgrade at the Tevatron collider. Detector performance and first results from $\bar pp$ collision data are presented.

S. Kuhlmann, H. Frisch, M. Cordelli, J. Huston

The physics program at the Fermilab Tevatron Collider will continue to explore the high energy frontier of particle physics until the commissioning of the LHC at CERN. The luminosity increase provided by the Main Injector will require upgrades beyond those implemented for the first stage (Run IIa) of the Tevatron&#39;s Run II physics program. The upgrade of

U. D. Jentschura, G. W. F. Drake

The current theoretical status of the Lamb shift in He+ is discussed. Recent calculations of two-loop binding corrections to the Lamb shift significantly shift the theoretical value of the &#34;classic&#34; Lamb shift in He+, i.e. of the 2S_1/2-2P_1/2-interval. In this brief research note, we present a new (theoretical) value for this interval which reads 14

E. Leticia Rojas, Feras M. O. Al-Dweri, Antonio M. Lallena, Coral Bodineau

The dosimetry for radiocolloid therapy of cystic craniopharyngiomas is investigated. Analytical calculations based on the Loevinger and the Berger formulae for electrons and photons, respectively, are compared with Monte Carlo simulations. The role of the material of which the colloid introduced inside the craniopharyngioma is made of as well as that forming

Niels Asger Mortensen, Martin Dybendal Nielsen

Cladding structures of photonic band-gap fibers often have air-holes of non-circular shape and, typically, close-to-hexagonal air holes with curved corners are observed. We study photonic band-gaps in such structures by aid of a two-parameter representation of the size and curvature. For the fundamental band-gap we find that the band-gap edges (the intersect

Daniel M. Zuckerman, Thomas B. Woolf

Systematic inaccuracy is inherent in any computational estimate of a non-linear average, such as the free energy difference (Delta-F) between two states or systems, because of the availability of only a finite number of data values, N. In previous work, we outlined the fundamental statistical description of this ``finite-sampling error.&#39;&#39; We now give

M. Waechter, F. Riess, H. Kantz, J. Peinke

This paper was withdrawn by the authors due to significant new findings. A new paper on the same topic has been submitted as physics/0310159.

W. Liu, C. M. Ko, V. Kubarovsky

The cross section for $Θ^+$ production from the reaction $γp\toπ^+K^-Θ^+$, which was observed in the CLAS experiment at the Jefferson National Laboratory, is evaluated in a hadronic model that includes couplings of $Θ^+$ to both $KN$ and $K^*N$. With their coupling constants determined from the empirical $πNN(1710)$ and $ρNN(1710)$ coupling constants using t

Kh. Gad, E. M. Darwish

The influence of hole-hole propagation in addition to the conventional particle-particle propagation, on the energy per nucleon and the momentum distribution is investigated. The results are compared to the Brueckner-Hartree-Fock (BHF) calculations with a continuous choice and conventional choice for the single-particle spectrum. The Bethe-Goldstone equation

Toshimitsu Yamazaki, Akinobu Dote, Yoshinori Akaishi

Using a phenomenological KN interaction combined with the method of Antisymmetrized Molecular Dynamics., we predict that few-body double-\kbar nuclei, such as ppK$^-$K$^-$ and ppnK$^-$K$^-$, as well as single-\kbar nuclei, are tightly bound compact systems with large binding energies and ultra-high nucleon densities. We point out that these \kbar nuclear clu

A. Baran, P. Mierzynski

The halo factor is one of the experimental data which describes a distribution of neutrons in nuclear periphery. In the presented paper we use Skyrme-Hartree (SH) and the Relativistic Mean Field (RMF) models and we calculate the neutron excess factor $Δ_B$ defined in the paper which differs slightly from halo factor $f_{\rm exp}$. The results of the calculat

D. C. Latimer, D. J. Ernst

A model of neutrino oscillation experiments is constructed. The experiments incorporated are: solar neutrinos (Chlorine, Gallium, Super-K, and SNO), reactor neutrinos (Bugey and CHOOZ), beam stop neutrinos (LSND decay at rest and decay in flight), and atmospheric neutrinos. Utilizing this model and the standard three-neutrino mixing extension of the standard

K. Kowalski, D. J. Dean, M. Hjorth-Jensen, T. Papenbrock

The standard and renormalized coupled cluster methods with singles, doubles, and noniterative triples and their generalizations to excited states, based on the equation of motion coupled cluster approach, are applied to the He-4 and O-16 nuclei. A comparison of coupled cluster results with the results of the exact diagonalization of the Hamiltonian in the sa

Su Houng Lee

The masses of charmonium states immersed in nuclear matter are calculated in LO QCD and in QCD sum rules. While the mass shift for $J/ψ$ are found to be less than -10 MeV, those for the $χ_{0,1,2}$ and $ψ(3686)$ and $ψ(3770)$ are found to be more than -40 MeV. We investigate the feasibility of observing such mass shifts in the future accelerator project at G

Richard Metzler, Yaneer Bar-Yam, Mehran Kardar

We reconsider the persistence of information under the dynamics of the logistic map in order to discuss communication through a nonlinear channel where the sender can set the initial state of the system with finite resolution, and the recipient measures it with the same accuracy. We separate out the contributions of global phase space shrinkage and local pha

F. Calogero, J-P. Françoise, M. Sommacal

Various solutions are displayed and analyzed (both analytically and numerically) of arecently-introduced many-body problem in the plane which includes both integrable and nonintegrable cases (depending on the values of the coupling constants); in particular the origin of certain periodic behaviors is explained. The light thereby shone on the connection among

Nikolai A. Kudryashov

Sampling equation method is presented to look for exact solutions of nonlinear differential equations. Application of this approach to one of the extensive chaos model is considered. Exact solutions of this model in travelling wave are given. Nonlinear evolution equation for the considered extensive chaos model is shown to have solitary and periodical waves.

Kaushik Majumdar

The present work discusses about a possible physical interpretation of the occurrence of turbulence in a dynamic fluid with mathematical modeling and computer simulation. Here turbulence is defined to be a phenomenon of random velocity field in the space-time continuum accompanied by chaotic occurrence of vortices. This interpretation is independent of the N

G. Giachetta, L. Mangiarotti, G. Sardanashvily

Though a global Chern-Simons (2k-1)-form is not gauge invariant, this form seen as a Lagrangian of higher-dimensional gauge theory leads to the conservation law of a modified Noether current.

Thomas G. Goodwillie

We study functors from spaces to spaces or spectra that preserve weak homotopy equivalences. For each such functor we construct a universal n-excisive approximation, which may be thought of as its n-excisive part. Homogeneous functors, meaning n-excisive functors with trivial (n-1)-excisive part, can be classified: they correspond to symmetric functors of n

J. Barros-Neto, Fernando Cardoso

We show how certain hypergeometric functions play an important role in finding fundamental solutions for a generalized Tricomi operator.

Paul Hacking

The minimal model program suggests a compactification of the moduli space of hyperplane arrangements which is a moduli space of stable pairs. Here, a stable pair consists of a scheme X which is a degeneration of projective space and a divisor D=D_1+..+D_n on X which is a limit of hyperplane arrangements. For example, in the 1-dimensional case, the stable pai

Cleon S. Barroso

In this paper, we deal with a class of semilinear elliptic equation in a bounded domain $Ω\subset\mathbb{R}^N$, $N\geq 3$, with $C\sp{1,1}$ boundary. Using a new fixed point result of the Krasnoselskii&#39;s type for the sum of two operators, an existence principle of strong solutions is proved. We give two examples where the nonlinearity can be critical.

Vincent M Guibout, Daniel J Scheeres

A methodology for solving two-point boundary value problems in phase space for Hamiltonian systems is presented. Using Hamilton-Jacobi theory in conjunction with the canonical transformation induced by the phase flow, we show that the generating functions for this transformation solve any two-point boundary value problem in phase space. Properties of the gen

Ethan D. Bloch

In a 1967 paper, Banchoff stated that a certain type of polyhedral curvature, that applies to all finite polyhedra, was zero at all vertices of an odd-dimensional polyhedral manifold; one then obtains an elementary proof that odd-dimensional manifolds have zero Euler characteristic. In a previous paper, the author defined a different approach to curvature fo

Paul D. Mitchener

This article corrects two mistakes in the article &#34;Coarse homology theories&#34; [math.AT/0106183].

Debashish Goswami, A. O. Kuku

We formulate a version of Baum-Connes&#39; conjecture for a discrete quantum group, building on our earlier work (\cite{GK}). Given such a quantum group $\cla$, we construct a directed family $\{\cle_F \}$ of $C^*$-algebras ($F$ varying over some suitable index set), borrowing the ideas of \cite{cuntz}, such that there is a natural action of $\cla$ on each $

Stanislav Dubrovskiy

We consider the space of germs of Fedosov structures at a point, together with the group of origin-preserving diffeomorphisms acting on it. We calculate dimensions of moduli spaces of $k$-jets of generic structures and construct Poincaré series. It is shown to be a rational function.

Khadiga Arwini, C. T. J. Dodson

We show that gamma distributions provide models for departures from randomness since every neighbourhood of an exponential distribution contains a neighbourhood of gamma distributions, using an information theoretic metric topology. We derive also the information geometry of the 3-manifold of McKay bivariate gamma distributions, which can provide a metrizati

Akira Ushijima

A generalized hyperbolic tetrahedra is a polyhedron (possibly non-compact) with finite volume in hyperbolic space, obtained from a tetrahedron by the polar truncation at the vertices lying outside the space. In this paper it is proved that a volume formula for ordinary hyperbolic tetrahedra devised by J. Murakami and M. Yano can be applied to such ones. Ther

D. V. Uvarov, A. A. Zheltukhin

The Hamiltonian of the simplest super $p$-brane model preserving 3/4 of the D=4 N=1 supersymmetry in the centrally extended symplectic superspace is derived and its symmetries are described. The constraints of the model are covariantly separated into the first- and the second-class sets and the Dirac brackets (D.B.) are constructed. We show the D.B. noncommu

V. A. Karmanov, J. -F. Mathiot, A. V. Smirnov

Within the framework of the covariant formulation of Light-Front Dynamics, we develop a nonperturbative renormalization scheme in the fermion model supposing that the composite fermion is a superposition of the &#34;bare&#34; fermion and a fermion+boson state. We first assume the constituent boson to be spinless. Then we address the case of gauge bosons in t

D. M&#34;ulsch, B. Geyer

It is shown that the Spin(7)-invariant super Yang-Mills theory in euight dimensions, which relies on the existence of the Caley invariant, permits the construction of a cohomological extension, which relies on the existence of the eight-dimensional analogue of the Pontryagin invariant arising from a quartic chiral primary operator.

A. W. Owen

We calculate tree level three and four point scattering amplitudes in type II string models with matter fields localized at the intersections of D-brane wrapping cycles. The analysis of the three point amplitude is performed in the context of Yukawa couplings and it is seen that a natural mechanism for the generation of a mass hierarchy arises. The four poin

M V Altaisky

It is shown that Euclidean field theory with polynomial interaction, can be regularized using the wavelet representation of the fields. The connections between wavelet based regularization and stochastic quantization are considered.

John Ellis, Keith A. Olive, Yudi Santoso, Vassilis C. Spanos

We present a likelihood analysis of the parameter space of the constrained minimal supersymmetric extension of the Standard Model (CMSSM), in which the input scalar masses m_0 and fermion masses m_{1/2} are each assumed to be universal. We include the full experimental likelihood function from the LEP Higgs search as well as the likelihood from a global prec

F. del Aguila, M. Perez-Victoria, J. Santiago

Models with extra dimensions may give new effects visible at future experiments. In these models, bulk fields can develop localized corrections to their kinetic terms which can modify the phenomenological predictions in a sizeable way. We review the case in which both gauge bosons and fermions propagate in the bulk, and discuss the limits on the parameter sp

F. del Aguila, M. Perez-Victoria, J. Santiago

In theories with branes, bulk fields get in general divergent corrections localized on these defects. Hence, the corresponding brane terms are renormalized and should be included in the effective theory from the very beginning. We review the phenomenology associated to brane kinetic terms for different spins and backgrounds, and point out that renormalizatio

Thomas Dent

We consider variation of coupling strengths and mass ratios in and beyond the Standard Model, in the light of various mechanisms of mass generation. In four-dimensional unified models, variations in charged particle thresholds, light quark masses and the electron mass can completely alter the (testable) relation between Delta ln alpha and Delta ln mu, where

A. Bialas

It is shown that the method of eliminating the statistical fluctuations from event-by-event analysis proposed recently by Fu and Liu can be rewritten in a compact form involving the generalized factorial moments.

Anders Tranberg, Jan Smit

We consider a scenario in which the baryon asymmetry was created in the early universe during a cold electroweak transition. The spinodal instability of the Higgs field caused by a rapid change of sign of its effective mass-squared parameter induces tachyonic preheating. We study the development of Chern-Simons number in this transition by numerical lattice

Henryk Czyz, Agnieszka Grzelinska

The impact of final-state radiation (FSR) on the radiative return method for the extraction of the e+e- hadronic cross section is discussed in detail. Possible experimental tests of the model dependence of FSR are proposed for the pi+pi- hadronic final state. The importance of the (pi+pi-photon) final state contribution to the muon anomalous magnetic moment

E. Meggiolaro

Supported by recent lattice results, we consider a scenario in which a U(1)-breaking condensate survives across the chiral transition in QCD. This scenario has important consequences on the pseudoscalar-meson sector, which can be studied using an effective Lagrangian model. In particular, generalizing the results obtained in a previous paper (where the zero-

M. V. Tokarev

The concept of z-scaling reflecting the general features of internal particle substructure, constituent interaction and mechanism of particle formation at high-pT is reviewed. Experimental data on inclusive cross sections obtained at U70, ISR, SpS, RHIC and Tevatron are used in the analysis. The properties of data z-presentation such as the energy independen

E. Iancu, K. Itakura, S. Munier

We show that the HERA data for the inclusive structure function F_2(x,Q^2) for x < 0.01 and 0.045 < Q^2 < 45 GeV^2 can be well described within the color dipole picture, with a simple analytic expression for the dipole-proton scattering amplitude, which is an approximate solution to the non-linear evolution equations in QCD. For dipole sizes less than the in

P. Faccioli, A. Schwenk, E. V. Shuryak

Studying the instanton-induced contributions to various hard exclusive reactions provides physical insight into the transition from the non-perturbative to the perturbative regime of QCD. To this end, we study the leading-instanton contribution to the electro-magnetic and transition formfactors, using an effective theory of the Instanton Liquid Model. We rep

Pedro Costa, M. C. Ruivo, Yu. L. Kalinovsky

We study the anomalous decays $π^0, η\toγγ$ in the framework of the three--flavor Nambu--Jona-Lasinio [NJL] model, in the vacuum and in quark matter in $β$ --equilibrium. It is found that the behavior of the relevant observables essentially reflects a manifestation of the partial restoration of chiral symmetry, in non strange and strange sectors. The probabi

L. B. Auerbach, R. L. Burman, D. O. Caldwell, E. D. Church

We observe a net beam-excess of $8.7 \pm 6.3$ (stat) $\pm 2.4$ (syst) events, above 160 MeV, resulting from the charged-current reaction of $ν_μ$ and/or $\barν_μ$ on C and H in the LSND detector. No beam related muon background is expected in this energy regime. Within an analysis framework of $π^0 \to ν_μ\barν_μ$, we set a direct upper limit for this branch

Jacques Bouchez, Mats Lindroos, Mauro Mezzetto

We give the present status of the beta-beam study, which aims at producing intense nue and antinue beams from the decay of relativistic radioactive io ns. The emphasis is put on recent technical progress and new ideas. The expected performances in terms of neutrino mixing parameters theta13 and CP violating phase delta using a megaton water Cerenkov detector

A. A. Sousa, J. W. Maluf

We study the gravitomagnetic effect in the context of absolute parallelism with the use of a modified geodesic equation via a free parameter b. We calculate the time difference in two atomic clocks orbiting the Earth in opposite directions and find a small correction due to the coupling between the torsion of the spacetime and the internal structure of atomi

Emilio Elizalde, John Quiroga H

We consider an Anti-de Sitter Universe filled by quantum CFT with classical phantom matter and perfect fluid. The model represents the combination of a trace-anomaly annihilated and a phantom driven Anti-de Sitter Universes. The influence exerted by the quantum effects and phantom matter on the AdS space is discussed. Different energy conditions in this type

Lars Andersson, Henk van Elst, Claes Uggla

The dynamics of Gowdy vacuum spacetimes is considered in terms of Hubble-normalized scale-invariant variables, using the timelike area temporal gauge. The resulting state space formulation provides for a simple mechanism for the formation of ``false&#39;&#39; and ``true spikes&#39;&#39; in the approach to the singularity, and a geometrical formulation for th

K. A. Bronnikov, B. E. Meierovich

We review some recent results concerning the properties of a spherically symmetric global monopole in $(D=d+2)$-dimensional general relativity. Some common features of monopole solutions are found independently of the choice of the symmetry-breaking potential. Thus, the solutions show six types of qualitative behavior and can contain at most one simple horiz

Francisco Lobo, Paulo Crawford

General Relativity is contaminated with non-trivial geometries which generate closed timelike curves. These apparently violate causality, producing time-travel paradoxes. We shall briefly discuss these geometries and analyze some of their physical aspects.

Jiuxing Liu, Weihang Jiang, Pete Wyckoff, Dhabaleswar K. Panda

For several years, MPI has been the de facto standard for writing parallel applications. One of the most popular MPI implementations is MPICH. Its successor, MPICH2, features a completely new design that provides more performance and flexibility. To ensure portability, it has a hierarchical structure based on which porting can be done at different levels. In

Catalin Pascu Moca, Gergely Zarand, Eugene Demler, Boldizsar Janko

We study the effect of magnetic Mn ions on the two-band superconductor MgB_2, and compute both the total and spin resolved scanning tunneling spectrum in the vicinity of the magnetic impurity. We show that when the internal structure of the Mn ion&#39;s $d$-shell is taken into account, multiple Shiba states appear in the spectrum. These multiplets were misse

W. L. Scopel, Antonio J. R. da Silva, W. Orellana, A. Fazzio

We perform ab initio calculations, based on density functional theory, of substitutional and vacancy defects in the monoclinic hafnium oxide (m-HfO2) and alpha-quartz (SiO2). The neutral oxygen vacancies and substitutional Si and Hf defects in HfO2 and SiO2, respectively, are investigated. Our calculations show that, for a large range of Hf chemical potentia

Chih-Yuan Tseng, Ariel Caticha

We explore the use of the method of Maximum Entropy (ME) as a technique to generate approximations. In a first use of the ME method the &#34;exact&#34; canonical probability distribution of a fluid is approximated by that of a fluid of hard spheres; ME is used to select an optimal value of the hard-sphere diameter. These results coincide with the results obt

Yu. A. Nastishin, M. F. Achard, H. T. Nguyen, M. Kleman

Observed under the polarizing microscope, the B7bis phase in the banana compound D14F3 [J.P. Bedel et al, Liq. Cryst., 27, 1411 (2000)] displays two types of textures of defects, namely (a): helical ribbons, that nucleate in large quantities when the samples are quenched from a sufficiently high temperature in the isotropic phase (b)- shapes with no helicity

A. Perucchi, L. Degiorgi, R. E. Thorne

We have measured the optical reflectivity $R(ω)$ of the quasi one-dimensional conductor $NbSe_{3}$ from the far infrared up to the ultraviolet between 10 and 300 $K$ using light polarized along and normal to the chain axis. We find a depletion of the optical conductivity with decreasing temperature for both polarizations in the mid to far-infrared region. Th

David Lancaster

Motivated by the problem of sorting, we introduce two simple combinatorial models with distinct Hamiltonians yet identical spectra (and hence partition function) and show that the local dynamics of these models are very different. After a deep quench, one model slowly relaxes to the sorted state whereas the other model becomes blocked by the presence of stab

Anton A. Burkov, Yogesh N. Joglekar, Enrico Rossi, Allan H. MacDonald

Filling factor $ν=1$ incompressible states in ideal bilayer quantum Hall systems have spontaneous interlayer phase coherence and can be regarded either as easy-plane pseudospin ferromagnets or as condensates of excitons formed from electrons in one layer and holes in the other layer. In this paper we discuss efforts to achieve an understanding of the two dif

A. Zheludev, T. Masuda, B. Sales, D. Mandrus

The quasi-one-dimensional bond-alternating S=1 quantum antiferromagnet NTENP is studied by single crystal inelastic neutron scattering. Parameters of the measured dispersion relation for magnetic excitations are compared to existing numerical results and used to determine the magnitude of bond-strength alternation. The measured neutron scattering intensities

Allan H. MacDonald, Anton A. Burkov, Yogesh N. Joglekar, Enrico Rossi

Double-layer electron systems in the quantum Hall regime have excitonic condensate ground states when the layers are close together and the total Landau level filling factor is close to an odd integer. In this paper we discuss the microscopic physics of these states and recent progress toward building a theory of the anomalous collective transport effects th

A. Fukaya, Y. Fudamoto, I. M. Gat, T. Ito

Muon spin relaxation ($μ$SR) and magnetic susceptibility measurements have been performed on the pure and diluted spin 1/2 kagomé system (Cu$_x$Zn$_{1-x}$)$_{3}$V$_{2}$O$_7$(OH)$_{2}$ 2H$_2$O. In the pure $x=1$ system we found a slowing down of Cu spin fluctuations with decreasing temperature towards $T \sim 1$ K, followed by slow and nearly temperature-inde

G. Tarjus, P. Viot

The parking-lot model provides a qualitative description of the main features of the phenomenology of granular compaction. We derive here approximate kinetic equations for this model, equations that are based on a $2-$parameter generalization of the statistical-mechanical formalism first proposed by Edwards and coworkers. We show that history-dependent effec

A. Fert, V. Cros, J. -M. George, J. Grollier

Reversing the magnetization of a ferromagnet by spin transfer from a current, rather than by applying a magnetic field, is the central idea of an extensive current research. After a review of our experiments of current-induced magnetization reversal in Co/Cu/Co trilayered pillars, we present the model we have worked out for the calculation of the current-ind

T. Ito, Y. Fudamoto, A. Fukaya, I. M. Gat-Malureanu

We report muon spin relaxation ($μ$SR) and magnetization measurements, together with synthesis and characterization, of the Li-intercalated layered superconductors Li$_{x}$HfNCl and Li$_{x}$ZrNCl with/without co-intercalation of THF (tetrahydrofuran) or PC (propylene carbonate). The 3-dimensional (3-d) superfluid density $n_{s}/m^{*}$ (superconducting carrie

Ryoichi Yamamoto, Yasuya Nakayama, Kang Kim

A new method is presented for mesoscopic simulations of particle dispersions in liquid crystal solvents. It allows efficient first-principle simulations of the dispersions involving many particles with many-body interactions mediated by the solvents. Demonstrations have been performed for the aggregation of colloid dispersions in two-dimensional nematic and

L. Pollet, S. Rombouts, K. Heyde, J. Dukelsky

A Bose-Hubbard model, describing bosons in a harmonic trap with a superimposed optical lattice, is studied using a fast and accurate variational technique (MF+NRG): the Gutzwiller mean-field (MF) ansatz is combined with a Numerical Renormalization Group (NRG) procedure in order to improve on both. Results are presented for one, two and three dimensions, with

J. Bravo-Abad, F. J. Garcia-Vidal, L. Martin-Moreno

In this paper we explore the transmission properties of single subwavelength apertures perforated in thin metallic films flanked by asymmetric configurations of periodic arrays of indentations. It is shown how the corrugation in the input side can be used to transmit selectively only two different wavelengths. Also, by tuning the geometrical parameters defin

Jean-Yves Fortin, Emmanuel Perez, Alain Audouard

Exact analytical results of the de Haas-van Alphen (dHvA) effect in an idealized two-band Fermi liquid with parabolic dispersion are presented. We consider a Fermi surface consisting in two electron bands with different band edges and band masses. Magnetic breakthrough (MB) between the bands is negligible. Analytical expressions of the dHvA Fourier amplitude

T. V. Shubina, S. V. Ivanov, V. N. Jmerik, D. D. Solnyshkov

Mie resonances due to scattering/absorption of light in InN containing clusters of metallic In may have been erroneously interpreted as the infrared band gap absorption in tens of papers. Here we show by direct thermally detected optical absorption measurements that the true band gap of InN is markedly wider than currently accepted 0.7 eV. Micro-cathodolumin

L. Petit, A. Svane, Z. Szotek, W. M. Temmerman

The electronic structures of several actinide solid systems are calculated using the self-interaction corrected local spin density approximation. Within this scheme the $5f$ electron manifold is considered to consist of both localized and delocalized states, and by varying their relative proportions the energetically most favourable (groundstate) configurati

P. Gallo, R. Pellarin, M. Rovere

We report the analysis in the wavevector space of the density correlator of a Lennard Jones binary mixture confined in a disordered matrix of soft spheres upon supercooling. In spite of the strong confining medium the behavior of the mixture is consistent with the Mode Coupling Theory predictions for bulk supercooled liquids. The relaxation times extracted f

Srutarshi Pradhan, Bikas K. Chakrabarti

We review here briefly the nature of precursors of global failures in three different kinds of many-body dynamical systems. First, we consider the lattice models of self-organised criticality in sandpiles and investigate numerically the effect of pulsed perturbations to the systems prior to reaching their respective critical points. We consider next, the ran

J. J. Brey, A. Prados

A one dimensional lattice model is formulated to study tapping dynamics and the long time steady distribution in granular media. The dynamics conserves the number of particles in the system, and density changes are associated to the creation and destruction of empty sites. The model is shown to be consistent with Edwards thermodynamics theory of powders. The

Ludovic Berthier, A. P. Young

We discuss the slow, nonequilibrium, dynamics of spin glasses in their glassy phase. We briefly review the present theoretical understanding of the spectacular phenomena observed in experiments and describe new numerical results obtained in the first large-scale simulation of the nonequilibrium dynamics of the three dimensional Heisenberg spin glass.

Artur Widera, Olaf Mandel, Markus Greiner, Susanne Kreim

We report on a two-particle matter wave interferometer realized with pairs of trapped 87Rb atoms. Each pair of atoms is confined at a single site of an optical lattice potential. The interferometer is realized by first creating a coherent spin-mixture of the two atoms and then tuning the inter-state scattering length via a Feshbach resonance. The selective c

H. Sakurai, K. Takada, F. Izumi, D. A. Dilanian

In order to investigate the role of the water molecules in Na$_{0.35}$CoO$_{2}\cdot$1.3H$_{2}$O, we synthesized superconducting Na$_{0.35}$CoO$_{2}\cdot$1.3H$_{2}$O and nonsuperconducting Na$_{0.35}$CoO$_{2}\cdot$0.7H$_{2}$O, and measured their normal-state magnetic susceptibilities. The susceptibility of Na$_{0.35}$CoO$_{2}\cdot$1.3H$_{2}$O has an enhanceme

M. Bier, L. Harnau, S. Dietrich

Interfaces between demixed fluid phases of binary mixtures of hard platelets are investigated using density-functional theory. The corresponding excess free energy functional is calculated within a fundamental measure theory adapted to the Zwanzig model, in which the orientations of the particles of rectangular shape are restricted to three orthogonal orient