June 2004 arXiv papers

K. M. Shen, F. Ronning, D. H. Lu, W. S. Lee

The evolution of Ca$_{2-x}$Na$_{x}$CuO$_{2}$Cl$_{2}$ from Mott insulator to superconductor was studied using angle-resolved photoemission spectroscopy. By measuring both the excitations near the Fermi energy as well as non-bonding states, we tracked the doping dependence of the electronic structure and the chemical potential with unprecedented precision. Our

M. Gronau, J. Zupan

Defining a most economical parametrization of time-dependent B-> rho^\pm pi^\mp decays, including a measurable phase alpha_{eff} which equals the weak phase alpha in the limit of vanishing penguin amplitudes, we propose two ways for determining alpha in this processes. We explain the limitation of one method, assuming only that two relevant tree amplitudes f

the STAR Collaboration, J. Adams

Correlations in the hadron distributions produced in relativistic Au+Au collisions are studied in the discrete wavelet expansion method. The analysis is performed in the space of pseudorapidity (|eta| < 1) and azimuth (full 2 pi) in bins of transverse momentum (p_t) from 0.14 < p_t < 2.1 GeV/c. In peripheral Au+Au collisions a correlation structure ascribed

William E. Baylis

A century after its formulation by Einstein, it is time to incorporate special relativity early in the physics curriculum. The approach advocated here employs a simple algebraic extension of vector formalism that generates Minkowski spacetime, displays covariant symmetries, and enables calculations of boosts and spatial rotations without matrices or tensors.

A. M. Zagoskin, M. Grajcar, A. N. Omelyanchouk

We predict a novel effect in a quantum two-level system (TLS) coupled to a resonant cavity. By bringing the TLS in and out of resonance with the cavity by a series of $N$ rectangular bias pulses (the length of the $m$th pulse scaling as $1/\sqrt{m}$), we will coherently excite the $N$-photon state, $|N,$ of the cavity only if the TLS was initially in an appr

Charles P. Boyer, Krzysztof Galicki, Paola Matzeu

We study eta-Einstein geometry as a class of distinguished Riemannian metrics on contact metric manifolds. In particular, we use a previous solution of the Calabi problem for Sasakian geometry to prove the existence of eta-Einstein structures on many different compact manifolds, including exotic spheres. We also relate these results to the existence of Einst

Chia-Chen Chang, Gun Sang Jeon, Jainendra K. Jain

When two-dimensional electrons are subjected to a very strong magnetic field, they are believed to form a triangular Wigner crystal. We demonstrate that, in the entire crystal phase, this crystal is very well represented by a composite-fermion-crystal wave function, revealing that it is not a simple Hartree-Fock crystal of electrons but an inherently quantum

STAR Collaboration, J. Adams

We present the first measurements of charge-dependent correlations on angular difference variables $η_1 - η_2$ (pseudorapidity) and $ϕ_1 - ϕ_2$ (azimuth) for primary charged hadrons with transverse momentum $0.15 \leq p_t \leq 2$ GeV/$c$ and $|η| \leq 1.3$ from Au-Au collisions at $\sqrt{s_{NN}} = 130$ GeV. We observe correlation structures not predicted by

Stefano Maghini, Alberto Santambrogio, Daniela Zanon

We compute the two-point function of Konishi-like operators up to one-loop order, in N=4 supersymmetric Yang-Mills theory. We work perturbatively in N=1 superspace. We find the expression expected on the basis of superconformal invariance and determine the normalization of the correlator and the anomalous dimension of the operators to order g^2 in the coupli

R. P. Ojha, A. R. Abate, D. J. Durian

The dynamics of a sphere fluidized in a nearly-levitating upflow of air were previously found to be identical to those of a Brownian particle in a two-dimensional harmonic trap, consistent with a Langevin equation [Ojha {\it et al.}, Nature {\bf 427}, 521 (2004)]. The random forcing, the drag, and the trapping potential represent different aspects of the int

Mario Leandro Aolita, Ignacio Garcia-Mata, Marcos Saraceno

We study many-qubit generalizations of quantum noise channels that can be written as an incoherent sum of translations in phase space. Physical description in terms of the spectral properties of the superoperator and the action in phase space are provided. A very natural description of decoherence leading to a preferred basis is achieved with diffusion along

Vasili Perebeinos, Marshall Newton

We use first principles density functional theory to calculate the electronic structure of the phenylthiolate (S-C$_6$H$_5$) self-assembled monolayer (SAM) on Cu(111) and Au(111) substrates. We find significant lateral dispersion of the SAM molecular states and discuss its implications for transport properties of the molecular wire array. We calculate the tw

J. P. B. C. de Melo

The pion electromagnetic form factor is calculated with a light-front quark model. The "plus" and "minus" component of the electromagnetic current are used to calculate the electromagnetic form factor in the Breit frame with two models for the q\bar{q} vertex. The light front constituent quark models describes very well hadronic wave function for pseudo-scal

M. Angeles Serrano, Marian Boguna, Albert Diaz-Guilera

We model the evolution of the Internet at the Autonomous System level as a process of competition for users and adaptation of bandwidth capability. We find the exponent of the degree distribution as a simple function of the growth rates of the number of autonomous systems and the total number of connections in the Internet, both empirically measurable quanti

Arjun Berera, Rudnei O. Ramos

The effective equation of motion is derived for a scalar field interacting with other fields in a Friedman-Robertson-Walker background space-time. The dissipative behavior reflected in this effective evolution equation is studied both in simplified approximations as well as numerically. The relevance of our results to inflation are considered both in terms o

M. Aguado, E. Seiler

Several years ago it was found that perturbation theory for two-dimensional O(N) models depends on boundary conditions even after the infinite volume limit has been taken termwise, provided $N>2$. There ensued a discussion whether the boundary conditions introduced to show this phenomenon were somehow anomalous and there was a class of `reasonable&#39; bound

R. G. Jafarov, V. E. Rochev

Two variants of the Nambu--Jona-Lasinio model -- the model with 4-dimensional cutoff and the model with dimensionally-analytical regularization -- are systematically compared. It is shown that they are, in essence, two different models of light-quark interaction. In the mean-field approximation the distinction becomes apparent in a behavior of scalar amplitu

Gabriel Vasseur, Dietmar Weinmann

We study the spectral statistics of interacting spinless fermions in a two-dimensional disordered lattice. Within a full quantum treatment for small few-particle-systems, we compute the low-energy many-body states numerically. While at weak disorder the interactions reduce spectral correlations and lead to localization, for the case of strong disorder we fin

T. R. Govindarajan, E. Harikumar

We show that the non-commutative $CP^1$ model coupled with Hopf term in 3 dimensions is equivalent to an interacting spin-$s$ theory where the spin $s$ of the dual theory is related to the coefficient of the Hopf term. We use the Seiberg-Witten map in studying this non-commutative duality equivalence, keeping terms to order $θ$ and show that the spin of the

D. Antonov, M. C. Diamantini

In this review, we discuss the confining and finite-temperature properties of the 3D SU(N) Georgi-Glashow model, and of 4D compact QED. At zero temperature, we derive string representations of both theories, thus constructing the SU(N)-version of Polyakov&#39;s theory of confining strings. We discuss the geometric properties of confining strings, as well as

Jeppe C. Dyre

It is shown that the elastic energy far from a point defect in an isotropic solid is mainly shear elastic energy. The calculation, which is based on a standard dipole expansion, shows that no matter how large or small the bulk modulus is compared to the shear modulus, less than 10% of the distant point defect energy is associated with volume changes.

T. M. Aliev, A. Ozpineci

The radiative decays of decuplet to octet baryons are analyzed within the light cone QCD sum rules framework.The electromagnetic transition form factors for these decays are calculated up to twist four accuracy for photon wave functions as well as including first order strange quark mass corrections. A comparison of our results with predictions of lattice th

Felix Ryde

We discuss gamma-ray bursts that have very hard spectra, consistent with black-body radiation, throughout their duration. We find that the temperature decay during a pulse can be well described by a broken power-law in time, with an initially constant or weak decay. After the break, most cases are consistent with a decay with index -2/3. Some pulses have a w

T. Yokoyama, Y. Tanaka, A. A. Golubov, J. Inoue

Charge transport in the diffusive normal metal (DN) / insulator / $s$- and $% d $-wave superconductor junctions is studied in the presence of magnetic impurities in DN in the framework of the quasiclassical Usadel equations with the generalized boundary conditions. The cases of $s$- and d-wave superconducting electrodes are considered. The junction conductan

Rina Kanamoto, Hiroki Saito, Masahito Ueda

An exact diagonalization study reveals that a matter-wave bright soliton and the Goldstone mode are simultaneously created in a quasi-one-dimensional attractive Bose-Einstein condensate by superpositions of quasi-degenerate low-lying many-body states. Upon formation of the soliton the maximum eigenvalue of the single-particle density matrix increases dramati

Zhengfeng Ji, Runyao Duan, Mingsheng Ying

We prove, in a multipartite setting, that it&#39;s always feasible to exactly transform a genuinely $m$-partite entangled state with sufficient many copies to any other $m$-partite state via local quantum operation and classical communication. This result affirms the comparability of multipartite pure entangled states.

Yaakov S. Weinstein, Timothy F. Havel, Joseph Emerson, Nicolas Boulant

The results of quantum process tomography on a three-qubit nuclear magnetic resonance quantum information processor are presented, and shown to be consistent with a detailed model of the system-plus-apparatus used for the experiments. The quantum operation studied was the quantum Fourier transform, which is important in several quantum algorithms and poses a

Constantin V. Usenko

The Wigner function of quantum systems is an effective instrument to construct the approximate classical description of the systems for which the classical approximation is possible. During the last time, the Wigner function formalism is applied as well to seek indications of specific quantum properties of quantum systems leading to impossibility of the clas

Giulio Chiribella, Giacomo Mauro D&#39;Ariano

We consider the convex set of positive operator valued measures (POVM) which are covariant under a finite dimensional unitary projective representation of a group. We derive a general characterization for the extremal points, and provide bounds for the ranks of the corresponding POVM densities, also relating extremality to uniqueness and stability of optimiz

Dominik Janzing, Pawel Wocjan

We propose a (theoretical ;-) model for quantum computation where the result can be read out from the time average of the Hamiltonian dynamics of a 2-dimensional crystal on a cylinder. The Hamiltonian is a spatially local interaction among Wigner-Seitz cells containing 6 qubits. The quantum circuit that is simulated is specified by the initialization of prog

I. Devetak

Recently Horodecki et al. [Phys. Rev. Lett. 90, 100402 (2003)] introduced an important quantum information processing paradigm, in which two parties sharing many copies of the same bipartite quantum state distill local pure states, by means of local unitary operations assisted by a one-way (two-way) completely dephasing channel. Local pure states are a valua

Peter Foldi

In this thesis concrete quantum systems are investigated in the framework of the environment induced decoherence. The focus is on the dynamics of highly nonclassical quantum states, the Wigner function of which are negative over some regions of their domains. One of the chosen physical systems is a diatomic molecule, where the potential energy of the nuclei

S. M. Arakelyan, A. V. Prokhorov, I. Vadeiko

We consider $Λ$-type model of the Bose-Einstein condensate of sodium atoms interacting with the light. Coefficients of the Kerr-nonlinearity in the condensate can achieve large and negative values providing the possibility for effective control of group velocity and dispersion of the probe pulse. We find a regime when the observation of the &#34;slow&#34; an

ZhongXiao Man

In this comment we point out that the &#39;quantum dialogue&#39; (Phys. Lett. A (in press); quant-ph/0406130) can be eavesdropped under the intercept-and-resend attack. We also give a revised control mode to detect this attack.

Masanori Ohya

We touch the problem of finding simplified models for the recognition process. We are interested in how the input signal arriving at the brain is entangled (connected) to the memory already stored and the consciousness that existed in the brain, and how a part of the signal will be finally stored as a memory.

Masanori Ohya

After Shannon, entropy becomes a fundamental quantity to describe not only uncertainity or chaos of a system but also information carried by the system. Shannon&#39;s important discovery is to give a mathematical expression of the mutual entropy (information), information transmitted from an input system to an output system, by which communication processes

Kei Inoue, Andrzej Kossakowski, Masanori Ohya

A measure describing the chaos of a dynamics was introduced by two complexities in information dynamics, and it is called the chaos degree. In particular, the entropic chaos degree has been used to characterized several dynamical maps such that logistis, Baker&#39;s, Tinckerbel&#39;s in classical or quantum systems. In this paper, we give a new treatment of

K. -H. Fichtner, W. Freudenberg, M. Ohya

We study a possible function of brain, in particular, we try to describe several aspects of the process of recognition. In order to understand the fundamental parts of the recognition process, the quantum teleportation scheme seems to be useful. We consider a channel expression of the teleportation process that serves for a simplified description of the reco

Masanori Ohya

The complexity and the chaos degree can be used to examine the chaotic aspects of not only several nonlinear classical and quantum physical physics but also life sciences. We will construct a model describing the function of brain in the context of Quantum Information Dynamics.

Stanislaw Szarek

In this note we give sharp estimates on the volume of the set of separable states on N qubits. In particular, the magnitude of the &#34;effective radius&#34; of that set in the sense of volume is determined up to a factor which is a (small) power of N, and thus precisely on the scale of powers of its dimension. Additionally, one of the appendices contains sh

T. Ochiai, J. C. Nacher, T. Akutsu

The advent of new experimental genomic technologies and the massive increase of DNA sequence information is helping researchers better understand how our genes work. Recently, experiments on mRNA abundance (gene expression) have revealed that gene expression shows a stationary organization described by a power-law distribution (scale-free organization) (i.e.

Georg Bison, Robert Wynands, Antoine Weis

Cardiomagnetometry is a growing field of noninvasive medical diagnostics that has triggered a need for affordable high-sensitivity magnetometers. Optical pumping magnetometers are promising candidates satisfying that need since it was demonstrated that they can map the heart magnetic field. For the optimization of such devices theoretical limits on the perfo

K. U. Schreiber, A. Velikoseltsev, M. Rothacher, T. Klugel

We report the first direct measurements of the very small effect of forced diurnal polar motion, successfully observed on three of our large ring lasers, which now measure the instantaneous direction of Earth&#39;s rotation axis to a precision of 1 part in 10^8 when averaged over a time interval of several hours. Ring laser gyroscopes provide a new viable te

Franco Laeri, Jens Noeckel

This book chapter is the first part of a review of nanoporous materials for optical applications. Whereas the second part [J.Sauer, F. Marlow and F.Schueth, pp. 153-172 of the same volume] discusses material properties, this part gives a self-contained discussion of fluorescence and lasing in dielectric microresonators, with special emphasis on the hexagonal

Vincent Debut, Jean Kergomard, Franck Laloe

Even if the tuning between the first and second register of a clarinet has been optimized by instrument makers, the lowest twelfths remain slightly too large (inharmonicity). In this article, we study the problem from two different points of view. First, we systematically review various physical reasons why this inharmonicity may take place, and the effect o

S. Fujii, H. Kamada, R. Okamoto, K. Suzuki

Binding energies of ^{3}H, ^{4}He, and ^{16}O are calculated, using low-momentum nucleon-nucleon interactions (V_{low-k}) for a wide range of the cutoff momentum Λ. In addition, single-particle energies in nuclei around ^{16}O are computed. The dependence of the binding energies and the single-particle energies in these nuclei on the cutoff momentum Λof the

A. N. Ivanov, M. Cargnelli, M. Faber, H. Fuhrmann

Within the Nambu-Jona-Lasinio model of light nuclei (the NNJL model), describing strong low-energy nuclear interactions, we compute the width of the energy level of the ground state of pionic deuterium. The theoretical value fits well the experimental data. Using the cross sections for the reactions nu_e + d -> p + p + e^- and nu_e + d -> p + n + nu_e, compu

P. Winter, R. Czyzykiewicz, H. -H. Adam, A. Budzanowski

We propose to extend the investigations of the eta meson production in nucleon-nucleon collisions by studying single and double polarization observables. Over the last years, the eta meson has been studied at several different experiments mainly by measurements of unpolarized total and differential cross sections. To reveal the production mechanism, polariza

Abigail G. Mitchell

Rook polynomials are a powerful tool in the theory of restricted permutations. It is known that the rook polynomial of any board can be computed recursively, using a cell decomposition technique of Riordan. In this paper, we give a new decomposition theorem, which yields a more efficient algorithm for computing the rook polynomial. We show that, in the worst

Jean-Philippe Jourdan

For a smooth manifold A, we consider the ordered configuration space F_k(AxR) of k distinct points in AxR. We obtain an explicit homotopy construction of the configuration space F_k(AxR) and of the (k-2)-fold suspension of F_k(A). Under certain conditions, we then show that the homotopy types of these two spaces depend only on the homotopy type of A. ----- P

Boris Y. Rubinstein

Explicit expressions for restricted partition function $W(s,{\bf d}^m)$ and its quasiperiodic components $W_j(s,{\bf d}^m)$ (called Sylvester waves) for a set of positive integers ${\bf d}^m = \{d_1, d_2, ..., d_m\}$ are derived. The formulas are represented in a form of a finite sum over Bernoulli polynomials of higher order with periodic coefficients.

Valentin Deaconu

Given a compact space X and two commuting continuous open surjective maps sigma_1, sigma_2 : X --> X, we construct certain C*-algebras that reflect the dynamics of the N^2-action. When the maps sigma_1, sigma_2 are local homeomorphisms, these are groupoid algebras, but in general, we will use a Cuntz-Pimsner algebra associated to a product system of Hilbert

Vadim E. Levit, Eugen Mandrescu

If for any $k$ the $k$-th coefficient of a polynomial I(G;x) is equal to the number of stable sets of cardinality $k$ in the graph $G$, then it is called the independence polynomial of $G$ (Gutman and Harary, 1983). Let $a$ be the size of a maximum stable set. Alavi, Malde, Schwenk and Erdos (1987)conjectured that I(T,x) is unimodal for any tree T, while, in

W. B. Vasantha Kandasamy, Florentin Smarandache

The introduction of Fuzzy Relational Equations (FREs) has made problems that were unsolvable using algebraic linear equations into solvable ones. FREs have been applied to problemsin medicine, industry, transportation and all types of social problems where the data is an unsupervised one. Yet, FREs lack the capacity to tackle problems where an element of ind

Francois Dahmani

We introduce a class of thin combings and prove that it has a nice behaviour in free constructions. Among corollaries, we deduce the relative metabolicity, in the sense of Gersten, of Sela&#39;s limit groups.

Lieven Le Bruyn

In this paper we associate to a qurve A (formerly known as a quasi-free or formally smooth algebra) the one-quiver Q(A) and dimension vector a(A). This pair contains enough information to reconstruct for all natural numbers n the GL(n)-etale local structure of the representation scheme rep(n,A). In an appendix we indicate how one might extend this to qurves

Pavel M. Bleher, Arno B. J. Kuijlaars

We give integral representations for multiple Hermite and multiple Hermite polynomials of both type I and II. We also show how these are connected with double integral representations of certain kernels from random matrix theory.

Alexander Gnedin, Sergey Kerov

We focus on derangement characters of $GL(n,q)$ which depend solely on the dimension of the space of fixed vectors. This family includes Thoma characters which become asymptotically irreducible as $n\to\infty$. We find explicit decomposition of Thoma characters into irreducibles, construct further derangement characters and seek for extremes in the family of

Jean-Pierre Wintenberger

We prove that there is no geometric $p$-adic representation of the Galois group of $\Q$ which is irreducible, of dimension 2, of conductor 1 and low weight, according to a conjecture of Fontaine and Mazur.

Steffen Hein

Dual scattering channel (DSC) schemes naturally extend the transmission line matrix (TLM) numerical method beyond the lines set up by P.B.JOHNS and coworkers. Conceptually, DSC schemes retain from TLM the typical formal splitting of the computed fields into incident and reflected components, interchanged and scattered between adjacent cells, without yet a ne

Andrew Hassell, Terence Tao, Jared Wunsch

We obtain an $L^4$ space-time Strichartz inequality for any smooth three-dimensional Riemannian manifold $(M,g)$ which is asymptotically conic at infinity and non-trapping, where $u$ is a solution to the Schrödinger equation $iu_t + {1/2} Δ_M u = 0$. The exponent $H^{1/4}(M)$ is sharp, by scaling considerations. In particular our result covers asymptotically

D. Bulacu, S. Caenepeel, F. Panaite

We show that all possible categories of Yetter-Drinfeld modules over a quasi-Hopf algebra $H$ are isomorphic. We prove also that the category $\yd^{\rm fd}$ of finite dimensional left Yetter-Drinfeld modules is rigid and then we compute explicitly the canonical isomorphisms in $\yd^{\rm fd}$. Finally, we show that certain duals of $H_0$, the braided Hopf alg

Denis Chebikin, Pavlo Pylyavskyy

For a directed graph G on vertices {0,1,...,n}, a G-parking function is an n-tuple (b_1,...,b_n) of non-negative integers such that, for every non-empty subset U of {1,...,n}, there exists a vertex j in U for which there are more than b_j edges going from j to G-U. We construct a family of bijective maps between the set P_G of G-parking functions and the set

Yves Le Jan, Sophie Lemaire

A discrete model of Brownian sticky flows on the unit circle is described: it is constructed with products of Beta matrices on the discrete torus. Sticky flows are defined by their ``moments&#39;&#39; which are consistent systems of transition kernels on the unit circle. Similarly, the moments of the discrete model form a consistent system of transition matr

Luis V. Dieulefait, V. Rotger

This note provides an insight to the diophantine properties of abelian surfaces with quaternionic multiplication over number fields. We study the fields of definition of the endomorphisms on these abelian varieties and the images of the Galois representations on their Tate modules. We illustrate our results with several explicit examples.

Katherine M. Benson, Tom Imbo

Symmetry breaking can produce ``Alice&#39;&#39; strings, which alter scattered charges and carry monopole number and charge when twisted into loops. Alice behavior arises algebraically, when strings obstruct unbroken symmetries -- a fragile criterion. We give a topological criterion, compelling Alice behavior or deforming it away. Our criterion, that π_o(H)

J. Kowalski-Glikman, Lee Smolin

We describe an extension of special relativity characterized by {\it three} invariant scales, the speed of light, $c$, a mass, $κ$ and a length $R$. This is defined by a non-linear extension of the Poincare algerbra, $\cal A$, which we describe here. For $R\to \infty$, $\cal A$ becomes the Snyder presentation of the $κ$-Poincare algebra, while for $κ\to \inf

Ingo Kirsch

We consider generalizations of the AdS/CFT correspondence in which probe branes are embedded in gravity backgrounds dual to either conformal or confining gauge theories. These correspond to defect conformal field theories (dCFT) or QCD-like theories with fundamental matter, respectively. Computing the quark condensate and the meson spectrum for a non-supersy

Diego Chialva, Roberto Iengo

Motivated also by recent revival of interest about metastable string states (as cosmic strings or in accelerator physics), we study the decay, in presence of dimensional compactification, of a particular superstring state, which was proven to be remarkably long-lived in the flat uncompactified scenario. We compute the decay rate by an exact numerical evaluat

Andrzej Staruszkiewicz

Let S(x) be a massless scalar quantum field which lives on the three-dimensional hyperboloid $xx= (x^0)^2-(x^1)^2-(x^2)^2-(x^3)^2=-1.$ The classical action is assumed to be $(\hbar=1=c)(8πe^2)^{-1}\int dx g^{ik}\partial_i S\partial_k S$, where $e^2$ is the coupling constant, $dx$ is the invariant measure on the de Sitter hyperboloid $xx=-1$ and $g_{ik}, i,k=

M. Yu. Kalmykov

Recent progress in analytical calculation of the multiple [inverse, binomial, harmonic] sums, related with epsilon-expansion of the hypergeometric function of one variable are discussed.

T. Binoth

We discuss algebraic/numeric methods to compute one-loop corrections for multiparticle/jet production cross sections. By using efficient reduction algorithms a compact expression for the gggγγ-> 0 amplitude is obtained. Further a numerical approach for 6-point 1-loop diagrams is presented.

G. L. Kane, Brent D. Nelson, Lian-Tao Wang, Ting T. Wang

We study the implications for the minimal supersymmetric standard model (MSSM) of the absence of a direct discovery of a Higgs boson at LEP. First we exhibit 15 physically different ways in which one or more Higgs bosons lighter than the LEP limit could still exist. For each of these cases -- as well as the case that the lightest Higgs eigenstate is at, or s

Geraldine Servant

We address the problem of baryon number violation in Randall-Sundrum backgrounds and provide a solution leading to a stable light Kaluza--Klein fermion in warped GUT. This adds to the list of dark matter candidates which stability can follow from ensuring proton stability in weak scale extensions of the Standard Model

P. Watson, W. Cassing, P. C. Tandy

The effect of quark-gluon vertex dressing on the ground state masses of the u/d-quark pseudoscalar, vector and axialvector mesons is considered with the Dyson-Schwinger equations. This extends the ladder-rainbow Bethe-Salpeter kernel to 2-loops. To render the calculations feasible for this exploratory study, we employ a simple infrared dominant model for the

German Rodrigo, Stefano Catani, Daniel de Florian, Werner Vogelsang

We consider the collinear limit of QCD amplitudes at one-loop order, and their factorization properties directly in colour space. These results apply to the multiple collinear limit of an arbitrary number of QCD partons, and are a basic ingredient in many higher-order computations. In particular, we discuss the triple collinear limit and its relation to flav

P. Faccioli, D. Guadagnoli, S. Simula

We investigate the role played by the fermionic determinant in the evaluation of the CP-violating neutron electric dipole moment (EDM) adopting the Instanton Liquid Model. Significant differences between quenched and unquenched calculations are found. In the case of unquenched simulations the neutron EDM decreases linearly with the quark mass and is expected

A. Denner, S. Dittmaier, M. Roth, M. M. Weber

Some of the most interesting Higgs-production processes at future e+ e- colliders are of the type e+ e- -> f anti-f H. We present a calculation of the complete O(alpha) corrections to these processes in the Standard Model for final-state neutrinos and top quarks. Initial-state radiation beyond O(alpha) at the leading-logarithmic level as well as QCD correcti

A. Ferroglia, G. Ossola, A. Sirlin

Recent experimental and theoretical progress in the M_H estimates from M_W and Sin^2_eff_lept is reviewed, with particular emphasis on the role played by M_t. Assuming that the SM is correct and taking into account the lower bound on M_H from direct searches, we derive restrictive bounds on M_W and M_t. We also discuss a representative ``benchmark&#39;&#39;

G. Heinrich

It is described how the method of sector decomposition can serve to disentangle overlapping infrared singularities, in particular those occurring in the calculation of the real emission part of e+e- to 2 jets and e+e- to 3 jets at NNLO.

B. B. Beard, M. Pepe, S. Riederer, U. J. Wiese

D-theory provides an alternative lattice regularization of the (1+1)-d CP(N-1) quantum field theory. In this formulation the continuous classical CP(N-1) fields emerge from the dimensional reduction of discrete SU(N) quantum spins. In analogy to Haldane&#39;s conjecture, ladders consisting of an even number of transversely coupled spin chains lead to a CP(N-

B. Aubert

The branching fractions of the decays B->K*0,gamma and B->K*+,gamma are measured using a sample of 88 x 10^6 B\bar{B} events collected with the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider. We find B(B->K*0,gamma) = 3.92 +/- 0.20 (stat) +/- 0.24 (syst) x 10^{-5} and B(B->K*_,gamma) = 3.87 +/- 0.28 (stat) +/- 0.26 (syst) x 10^{-5}. Our measu

Jan Stark

The Fermilab Tevatron (p pbar), operating at sqrt(s)=1.96 TeV, is a rich source of B hadrons. The large acceptance in terms of rapidity and transverse momentum of the charged particle tracking system and the muon system make the upgraded Run II D0 detector an excellent tool for B physics. In this article, we report on selected physics results based on the fi

Regina Demina

CDF and D0 collaborations analyzed up to 200 pb-1 of the delivered data in search for different supersymmetry signatures, so far with negative results. We present results on searches for chargino and neutralino associated production, squarks and gluinos, sbottom quarks, gauge mediated SUSY breaking and long lived heavy particles.

Eugenio Paoloni

Recent BaBar results on rare B decays involving flavour-changing neutral currents or purely leptonic final states are presented. New measurements of the CP asymmetries in B -> K* gamma, B -> K*2(1430) gamma, and b -> s gamma are reported, as well as a new measurement of the B -> K* gamma branching fraction. Also reported are updated limits on B -> mu nu and

A. Freise

The French-Italian interferometric gravitational wave detector VIRGO is currently being commissioned. Its principal instrument is a Michelson interferometer with 3 km long optical cavities in the arms and a power-recycling mirror. This paper gives an overview of the present status of the system. We report on the presently attained sensitivity and the system&

Bartolomé Coll, Joan Josep Ferrando

The Stephani universes that can be interpreted as an ideal gas evolving in local thermal equilibrium are determined. Five classes of thermodynamic schemes are admissible, which give rise to five classes of regular models and three classes of singular models. No Stephani universes exist representing an exact solution to a classical ideal gas (one for which th

Dorje C. Brody, Lane P. Hughston

A generalised equivalence principle is put forward according to which space-time symmetries and internal quantum symmetries are indistinguishable before symmetry breaking. Based on this principle, a higher-dimensional extension of Minkowski space is proposed and its properties examined. In this scheme the structure of space-time is intrinsically quantum mech

Alan A. Coley, Sigbjorn Hervik

We use a dynamical systems approach to study Bianchi type VI$_0$ cosmological models containing two tilted $γ$-law perfect fluids. The full state space is 11-dimensional, but the existence of a monotonic function simplifies the analysis considerably. We restrict attention to a particular, physically interesting, invariant subspace and find all equilibrium po

H. Cebeci, T. Dereli

We study models of axi-dilaton gravity in space-time geometries with torsion. We discuss conformal re-scaling rules in both Riemannian and non-Riemannian formulations. We give static, spherically symmetric solutions and examine their singularity structure.

Miguel Alcubierre, Jose A. Gonzalez, Marcelo Salgado, Daniel Sudarsky

We review the arguments and counter arguments about the recent proposal for generic censorship violation. In particular the argument made in gr-qc/0405050 against our proposal for a possible expanding domain wall that could encompass a large black hole, is shown to have a serious flaw. Other problems of the original idea are also discussed.

Scott Aaronson

A celebrated 1976 theorem of Aumann asserts that honest, rational Bayesian agents with common priors will never &#34;agree to disagree&#34;: if their opinions about any topic are common knowledge, then those opinions must be equal. Economists have written numerous papers examining the assumptions behind this theorem. But two key questions went unaddressed: f

Claude Ederer, Nicola A. Spaldin

We analyze the coupling between the ferroelectric and magnetic order parameters in the magnetoelectric multiferroic BiFeO_3 using density functional theory within the local spin density approximation and the LSDA+U method. We show that weak ferromagnetism of the Dzyaloshinskii-Moriya type occurs in this material, and we analyze the coupling between the resul

R. P. Panguluri, Changgan Zeng, H. H. Weitering, J. M. Sullivan

Germanium-based alloys hold great promise for future spintronics applications, due to their potential for integration with conventional Si-based electronics. Mn5Ge3 exhibits strong ferromagnetism up to the Curie temperature Tc~295K. We use Point Contact Andreev Reflection (PCAR) spectroscopy to measure the spin polarization of Mn5Ge3 epilayers grown by solid

F. A. B. F. de Moura, M. L. Lyra, F. Dominguez-Adame, V. A. Malyshev

We study the dynamics of an electron subjected to a static uniform electric field within a one-dimensional tight-binding model with a slowly varying aperiodic potential. The unbiased model is known to support phases of localized and extended one-electron states separated by two mobility edges. We show that the electric field promotes sustained Bloch oscillat

Teemu Murtola, Emma Falck, Michael Patra, Mikko Karttunen

We construct a coarse-grained (CG) model for dipalmitoylphosphatidylcholine (DPPC)/cholesterol bilayers and apply it to large-scale simulation studies of lipid membranes. Our CG model is a two-dimensional representation of the membrane, where the individual lipid and sterol molecules are described by point-like particles. The effective intermolecular interac

Vittoria Colizza, Jayanth R. Banavar, Amos Maritan, Andrea Rinaldo

We present an analysis of the topologies of a class of networks which are optimal in terms of the requirements of having as short a route as possible between any two nodes while yet keeping the congestion in the network as low as possible. Strikingly, we find a variety of distinct topologies and novel phase transitions between them on varying the number of l

Jacqueline Appell, Christian Ligoure, Gregoire Porte

Microemulsion droplets (oil in water stabilized by a surfactant film) are progressively decorated with increasing amounts of poly ethylene- oxide (PEO) chains anchored in the film by the short aliphatic chain grafted at one end of the PEO chain . The evolution of the bending elasticity of the surfactant film with increasing decoration is deduced from the evo

C. J. de Matos, M. Tajmar

Starting from the generalised London equations, which include a gravitomagnetic term, the gravitational and the electromagnetic properties of superconductors are derived. A phenomenological synthesis of those properties is proposed.

Luca Angelani, Lapo Casetti, Marco Pettini, Giancarlo Ruocco

The elsewhere surmised topological origin of phase transitions is given here new important evidence through the analytic study of an exactly solvable model for which both topology and thermodynamics are worked out. The model is a mean-field one with a k-body interaction. It undergoes a second order phase transition for k=2 and a first order one for k>2. This