November 2004 arXiv papers — page 3

X. L. Lei, S. Y. Liu

Recently discovered modulations of Shubnikov-de Haas oscillations in microwave-irradiated two-dimensional electron systems are shown to arise from electron heating induced by the radiation. The electron temperature, obtained by balancing the energy absorption from the microwave field and the energy dissipation to the lattice through realistic electron-phonon

G. J. Gounaris, J. Layssac, P. I. Porfyriadis, F. M. Renard

The common belief that the lightest supersymmetric particle (LSP) might be a neutralino, providing also the main Dark Matter (DM) component, calls for maximal detail in the study of the neutralino properties. Motivated by this, we consider the direct production of a single neutralino $\tchi^0_i$ at a high/energy hadron collider, focusing on the $\tchi^0_1$ a

Tom G. Mackay, Sandi Setiawan, Akhlesh Lakhtakia

Examining the propagation of electromagnetic plane waves with the wavevector directed in opposition to the time-averaged Poynting vector in cosmological spacetime with piecewise uniform metric, we show that such negative-phase-velocity (NPV) propagation is possible in certain de Sitter spacetimes but not in anti-de Sitter spacetimes. This difference suggests

Mohammad Abolhassani

The potential energy of a system in stable equilibrium has a minimum value. This property is used to derive a formula that is useful in determi- nation of stability of a floating body. It is found that a floating body is in stable equilibrium if its center of gravity has a minimum height with respect to its related center of buoyancy.

Frederic Dambreville

In this paper a conditional logic is defined and studied. This conditional logic, Deterministic Bayesian Logic, is constructed as a deterministic counterpart to the (probabilistic) Bayesian conditional. The logic is unrestricted, so that any logical operations are allowed. This logic is shown to be non-trivial and is not reduced to classical propositions. Th

J. F. Corney, P. D. Drummond

We introduce a positive phase-space representation for fermions, using the most general possible multi-mode Gaussian operator basis. The representation generalizes previous bosonic quantum phase-space methods to Fermi systems. We derive equivalences between quantum and stochastic moments, as well as operator correspondences that map quantum operator evolutio

Tetsuji Kimura

We study gauged linear sigma models for noncompact Calabi-Yau manifolds described as a line bundle on a hypersurface in a projective space. This gauge theory has a unique phase if the Fayet-Iliopoulos parameter is positive, while there exist two distinct phases if the parameter is negative. We find four massless effective theories in the infrared limit, whic

Ashoke Sen

It has recently been shown that if we take into account a class of higher derivative corrections to the effective action of heterotic string theory, the entropy of the black hole solution representing elementary string states correctly reproduces the statistical entropy computed from the degeneracy of elementary string states. So far the form of the solution

Davide Lazzati

We study a sample of bright long BATSE GRB light curves in the 200 s before the detection of the GRB prompt emission. We find that in a sizable fraction of cases (20 %) there is evidence of emission above the background coming from the same direction of the GRB. This emission is characterised by a softer spectrum with respect to the main one and contains a s

Steven S. Gubser

The D2-D0 bound state exhibits a Gregory-Laflamme instability when it is sufficiently non-extremal. If there are no D0-branes, the requisite non-extremality is finite. When most of the extremal mass comes from D0-branes, the requisite non-extremality is very small. The location of the threshhold for the instability is determined using a local thermodynamic a

Zilvinas Rinkevicius, Gennady P. Berman, David. L. Allara, Vladimir I. Tsifrinovich

We suggest the application of nitronylnitroxide substituted with methyl group and 2,2,6,6-tetramethylpiperidin organic radicals as 1/2-spin qubits for self-assembled monolayer quantum devices. We show that the oscillating cantilever driven adiabatic reversals technique can provide the read-out of the spin states. We compute components of the $g$-tensor and d

Francisco J. Gomez, Javier Sesma

A very simple procedure to calculate eigenenergies of quantum anharmonic oscillators is presented. The method, exact but for numerical computations, consists merely in requiring the vanishing of the Wronskian of two solutions which are regular respectively at the origin and at infinity. The first one can be represented by its series expansion; for the second

Bernd Kuckert, Jens Mund

Recently a sufficient and necessary condition for Pauli's spin- statistics connection in nonrelativistic quantum mechanics has been established [quant-ph/0208151]. The two-dimensional part of this result is extended to n-particle systems and reformulated and further simplified in a more geometric language.

Ming Yang, Zhuo-Liang Cao

A deterministic teleportation scheme for unknown atomic states is proposed in cavity QED. The Bell state measurement is not needed in the teleportation process, and the success probability can reach 1.0. In addition, the current scheme is insensitive to the cavity decay and thermal field.

A. Laszkiewicz, S. Cebrat, D. Stauffer

We have analysed the possibility of scaling the sexual Penna ageing model. Assuming that the number of genes expressed before the reproduction age grows linearly with the genome size and that the mutation rate per genome and generation is constant, we have found that the fraction of defective genes expressed before the minimum reproduction age drops with the

D. A. Vereshchagin, S. B. Leble, M. A. Solovchuk

The problem of wave disturbance propagation in rarefied gas in gravity field is explored. The system of hydrodynamic-type equations for a stratified gas in gravity field is derived from BGK equation by method of piecewise continuous partition function. The obtained system of the equations generalizes the Navier-Stokes at arbitrary density (Knudsen numbers).

V. A. Yerokhin, A. N. Artemyev, V. M. Shabaev, G. Plunien

We present an ab initio calculation of the screened self-energy correction for (1s)^2 2p3/2 and (1s)^2 2s states of Li-like ions with nuclear charge numbers in the range Z = 12-100. The evaluation is carried out to all orders in the nuclear-strength parameter Z α. This investigation concludes our calculations of all two-electron QED corrections for the 2p3/2

Seung-Il Nam, Atsushi Hosaka, Hyun-Chul Kim

We investigate Theta^+ production via gamma N and NN reactions in order to obtain information on the structure of Theta^+, especially its parity. We observe that the positive parity. Theta^+production provides about ten times total cross sections than those of the negative parity one in both photon and nucleon induced reactions due to P-wave enhancement of t

Ad. R. Raduta

The exponential scaling of isotopic yields is investigated for sources of different sizes over a broad range of excitation energies and freeze-out volumes, in both primary and asymptotic stages of the decay in the framework of a microcanonical multifragmentation model. It was found that the scaling parameters have a strong dependence on the considered pair o

A. Keranen, F. Becattini, V. V. Begun, M. I. Gorenstein

Even though the first momenta i.e. the ensemble average quantities in canonical ensemble (CE) give the grand canonical (GC) results in large multiplicity limit, the fluctuations involving second moments do not respect this asymptotic behaviour. Instead, the asymptotics are strikingly different, giving a new handle in study of statistical particle number fluc

P. Braun-Munzinger

In nucleus-nucleus collisions at ultra-relativistic energies matter is formed with initial energy density significantly exceeding the critical energy density for the transition from hadronic to partonic matter. We will review the experimental evidence for this new form of matter - the Quark-Gluon Plasma - from recent experiments at the SPS and RHIC with emph

M. Rudnev, A. V. Yurov, V. A. Yurov

A new nonlinear 3+1 dimensional evolution equation admitting the Lax pair is presented. In the case of one spatial dimension, the equation reduces to the Burgers equation. A method of construction of exact solutions, based on a class of discrete symmetries of the former equation is developed. These symmetries reduce to the Cole-Hopf transformation in one-dim

Francois Holtz, Sascha Lenne, Guido Ventura, Francesco Vetere

A dome from Lipari Island (Southern Italy) consists of 12 vol. percent of circular, elongated and folded latitic enclaves hosted in a rhyolitic matrix. The dm- to cm-scale enclaves are more deformed than the mm-scale blobs. The critical value of the ratio between the viscous forces, which allow deformation and eventually break up blobs of latitic magma, and

Albert Ferrando

The most general form for symmetric modes of nonlinear discrete-symmetry systems with nonlinearity depending on the modulus of the field is presented. Vortex solutions are demonstrated to behave as Bloch modes characterized by an angular Bloch momentum associated to a periodic variable, periodicity being fixed by the order of discrete point-symmetry of the s

V. N. Plechko

The two-dimensional Ising model is representable as a lattice free-fermion field theory in terms of the integral over anticommuting Grassmann variables. The exact solution in a zero magnetic field then follows by evaluating Gaussian fermionic integral for partition function. It is argued that by switching on of a non-zero magnetic field the non-local and non

Volker Betz, Stefan Teufel

For multi-level time-dependent quantum systems one can construct superadiabatic representations in which the coupling between separated levels is exponentially small in the adiabatic limit. Based on results from [BeTe1] for special Hamiltonians we explicitly determine the asymptotic behavior of the exponentially small coupling term for generic two-state syst

G. I. Garasko

We introduce the notion of the generalized-analytical function of the poly-number variable, which is a non-trivial generalization of the notion of analytical function of the complex variable and, therefore, may turn out to be fundamental in theoretical physical constructions. As an example we consider in detail the associative-commutative hypercomplex number

Leonid Lantsman

The well-known Bogomol'nyi-Prasad-Sommerfeld (BPS) monopole is considered in the limit of the infinite mass of the Higgs field as a basis for constructing the Yang-Mills vacuum with the finite energy density. In this limit the Higgs field disappears at the spatial infinity, but it leaves, nevertheless, its trace as vacuum Yang-Mills BPS monopoles transfo

David Bessis

Let $V$ be a finite dimensional complex vector space and $W\subset \GL(V)$ be a finite complex reflection group. Let $V^{\reg}$ be the complement in $V$ of the reflecting hyperplanes. A classical conjecture predicts that $V^{\reg}$ is a $K(pi,1)$ space. When $W$ is a complexified real reflection group, the conjecture follows from a theorem of Deligne. Our ma

Vladimir Shpilrain, Alexander Ushakov

The conjugacy search problem in a group G is the problem of recovering an x in G from given g in G and h=x^{-1}gx. This problem is in the core of several recently suggested public key exchange protocols, most notably the one due to Anshel, Anshel, and Goldfeld, and the one due to Ko, Lee at al. In this note, we make two observations that seem to have eluded

Iustin Coanda, Guenther Trautmann

We show that the idea used by Kempf (1990) in order to obtain a splitting criterion for vector bundles on projective spaces leads to an elementary proof of the Babylonian tower theorem for this class of bundles, a result due to Barth--Van de Ven (1974) in the rank 2 case and to Sato (1977) and Tyurin (1976) in the case of arbitrary rank. As a byproduct we ob

G. Sardanashvily

We consider a Lagrangian system on a fiber bundle and its gauge transformations depending on derivatives of dynamic variables and gauge parameters of arbitrary order. We say that gauge transformations form an algebra if they generate a nilpotent BRST operator.

Joern Mueller, Werner Mueller

We study the asymptotic behaviour of regularized determinants of certain Laplace type operators with respect to singular deformations of the underlying manifold which are obtained by stretching a tubular neighborhood of an embedded separating hypersurface to a cylinder of infinite length. Using the asymptotic expansions, we derive adiabatic splitting formula

Valery Marenich

As the first step in the direction of the Hopf conjecture on the non-existence of metrics with positive sectional curvature on $S^2 \times S^2$ D.Gromoll and K.Tapp in [GT] suggested the following (Weak Hopf) conjecture (on the rigidity of non-negatively curved metrics on $S^2 \times R^3$): "The boundary $S^2\times S^2$ of the $S^2 \times B^3\subset S^2

Ser Peow Tan, Yan Loi Wong, Ying Zhang

Greg McShane introduced a remarkable identity for the lengths of simple closed geodesics on cusped hyperbolic surfaces. This was subsequently generalized by the authors to hyperbolic cone-surfaces, possibly with cusps and/or geodesic boundary. In this paper, we generalize the identity further to the case of classical Schottky groups. As a consequence, we obt

T. Hasanis, A. Savas-Halilaj, T. Vlachos

We investigate complete minimal hypersurfaces in the Euclidean space $% \ {R}^{4}$, with Gauss-Kronecker curvature identically zero. We prove that, if $f:M^{3}\to {R}^{4}$ is a complete minimal hypersurface with Gauss-Kronecker curvature identically zero, nowhere vanishing second fundamental form and scalar curvature bounded from below, then $f(M^{3})$ split

Xiang Tang

In this note, we will show one example of hamiltonian Lie algebra action which has no invariant star product.

I. Heckenberger

Yetter--Drinfel'd modules of diagonal type admit an equivalence relation which conjecturally preserves dimension and Gel'fand--Kirillov dimension of the corresponding Nichols algebras. This relation is determined explicitly for all rank 2 Yetter--Drinfeld modules where the Gel'fand--Kirillov dimension is known to be finite. Key Words: Brandt grou

G. J. Chaitin

We discuss mathematical and physical arguments against continuity and in favor of discreteness, with particular emphasis on the ideas of Emile Borel (1871-1956).

Anna Karczewska

In the paper we study stochastic convolution appearing in Volterra equation driven by so called Lévy process. By Lévy process we mean a process with homogeneous independent increments, continuous in probability and cadlag.

Marius Ionescu

We describe a method for associating some non-self-adjoint algebras to Mauldin-Williams graphs and we study the Morita equivalence and isomorphism of these algebras. We also investigate the relationship between the Morita equivalence and isomorphism class of the C^{\ast} -correspondences associated with Mauldin-Williams graphs and the dynamical properties of

Marc Herzlich

We prove that the round metric on the sphere has the largest first eigenvalue of the Dirac operator among all metrics that are larger than it. As a corollary, this gives an alternative proof of an extremality result for scalar curvature due to M. Llarull.

Anthony Iarrobino

We determine the codimension of the Betti strata of the family G(H) parametrizing graded Artinian quotients A of the polynomial ring R in two variables, having Hilbert function H. The Betti stratum G(B,H) parametrizes all such quotients having the graded Betti numbers determined by the relation degrees B. Our method is to identify G(B,H) as the product of de

Martin Scharlemann

This is a chapter that is to appear in the "Handbook of Knot Theory", edited by William W. Menasco and Morwen B. Thistlethwaite.

Paolo Creminelli, Alberto Nicolis, Matias Zaldarriaga

For bouncing cosmologies such as the ekpyrotic/cyclic scenarios we show that it is possible to make predictions for density perturbations which are independent of the details of the bouncing phase. This can be achieved, as in inflationary cosmology, thanks to the existence of a dynamical attractor, which makes local observables equal to the unperturbed solut

Carlos Alberto Santos Almeida, Makarius Oliveira Tahim

In the last years higher dimensional physics has won importance. Despite the Superstrings, higher dimensional effects, in measurable scales of energy (some TeV), became only possible with Randall-Sundrum's models (RS). In particular, recent studies in neutrino and axion physics have proposed new and interesting questions about neutrino mixings and new sc

Sergio Benvenuti, Amihay Hanany

All superconformal quivers are shown to satisfy the relation c = a and are thus good candidates for being the field theory living on D3 branes probing CY singularities. We systematically study 3 block and 4 block chiral quivers which admit a superconformal fixed point of the RG equation. Most of these theories are known to arise as living on D3 branes at a s

Nadav Drukker

We discuss how closed time-like curves can be eliminated from certain supergravity backgrounds by inclusion of domain-walls made of supertubes. Special emphasis is given to the mechanism by which the supertubes spread into domain walls, which is similar to the enhanceon mechanism. Lecture notes from my talk at the RTN meeting in Kolymbari, Crete, September 2

Brandon Carter

This course is designed to give a mathematically coherent introduction to the classical thory of black holes and also of strings and membranes (which are like the horizon of a black hole in being examples of physical systems based on a dynamically evolving world sheet) giving particular attention given to the study of the geometry of their equilibrium states

Ignacio Navarro, Jose Santiago

We compute the matching conditions for a general thick codimension 2 brane, a necessary previous step towards the investigation of gravitational phenomena in codimension 2 braneworlds. We show that, provided the brane is weakly curved, they are specified by the integral in the extra dimensions of the brane energy-momentum, independently of its detailed inter

Michael Chesterman

We describe the complete cohomology of the Berkovits BRST operator for the superparticle. It is non-zero at eight ghost numbers, splitting into two quartets, the members of each quartet being completely isomorphic. Based only on considerations of the isomorphisms of the cohomology, and using only the standard inner product, we derive the inner product approp

Michael Lublinsky

We present a short review of recent theoretical activity which is an attempt to learn about low $x$ evolution beyond the Balitsky - Kovchegov equation.

R. Vogt

We study medium modifications of J/psi production in cold nuclear media in deuterium-nucleus collisions. We discuss several parameterizations of the modifications of the parton densities in the nucleus, known as shadowing, an initial-state effect. We also include absorption of the produced J/psi by nucleons, a final-state effect. Both spatially homogeneous a

Z. Was, P. Golonka

The status of the Monte Carlo programs for the simulation of tau-lepton production and decay in high-energy accelerator experiments is reviewed. In particular, the status of the following packages is discussed: (i) TAUOLA for tau-lepton decay, (ii) PHOTOS for radiative corrections in decays, (iii) MC-TESTER packages for various types of semi-automatic tests,

Z. X. Sun, L. Y. Xiao, Z. G. Xiao, H. Q. Zheng

We briefly review the recent progresses in the new unitarization approach being developed by us. Especially we discuss the large $N_c$ $ππ$ scatterings by making use of the partial wave $S$ matrix parametrization form. We find that the $σ$ pole may move to the negative real axis on the second sheet of the complex $s$ plane, therefore it raises the interestin

Carlo Ewerz

Chiral symmetry breaking in QCD leads to the emergence of pions as Goldstone bosons. Their existence in turn affects the Green functions of the theory. Here we study the effect of pion corrections on the light quark's Green function in Feynman gauge using the framework of Gribov's approach to the Dyson-Schwinger equation.

Andrzej J. Buras, Robert Fleischer, Stefan Recksiegel, Felix Schwab

We summarize a recent strategy for a global analysis of the B -> pi pi, pi K systems and rare decays. We find that the present B -> pi pi and B -> pi K data cannot be simultaneously described in the Standard Model. In a simple extension in which new physics enters dominantly through Z^0 penguins with a CP-violating phase, only certain B -> pi K modes are aff

W. J. Stirling

Quantum Chromodynamics is an established part of the Standard Model and an essential part of the toolkit for searching for new physics at high-energy colliders. I present a status report on the theory of QCD and review some of the important developments in the past year.

Contreras H. Carlos

Methods of Borel integration to calculate the binding ground energies and mass of b-barb quarkonia are presented. The methods take into account the leading infrared renormalon structure of the "soft" binding energy E(s) and of the quark pole masses mq, and the property that the contributions of these singularities in M(s) = 2 mq + E(s) cancel.

John Ellis

There are several different experimental indications, such as the pion-nucleon sigma term and polarized deep-inelastic scattering, which suggest that the nucleon wave function contains a hidden s bar s component. This is expected in chiral soliton models, which also predicted the existence of new exotic baryons that may recently have been observed. Another h

S. Kanemura, Y. Kuno, M. Kuze, T. Ota

A deep inerastic scattering process \mutau is discussed to study lepton flavor violation between muons and tau leptons. In supersymmetric models, the Higgs boson mediated diagrams could be important for this reaction. We find that at a muon energy ($E_μ$) higher than 50 GeV, the predicted cross section significantly increases due to the contribution from sea

R. Alkofer, W. Detmold, C. S. Fischer, P. Maris

The results of different non-perturbative studies agree on a power law as the infrared behavior of the Landau gauge gluon propagator. This propagator violates positivity and thus indicates the absence of the transverse gluons from the physical spectrum, i.e. gluon confinement. A simple analytic structure for the gluon propagator is proposed capturing all of

Ingunn Kathrine Wehus, Finn Ravndal

Using the language of differential forms, the Kaluza-Klein theory in 4+1 dimensions is derived. This theory unifies electromagnetic and gravitational interactions in four dimensions when the extra space dimension is compactified. Without any ad-hoc assumptions about the five-dimensional metric, the theory also contains a scalar field coupled to the other fie

Yi Wei, Tilo Wettig

We extend Zirnbauer's color-flavor transformation in the bosonic sector to the color group SU(N_c). Because the flavor group U(N_b, N_b) is non-compact, the algebraic method by which the original color-flavor transformation was derived leads to a useful result only for 2N_b \le N_c. Using the character expansion method, we obtain a different form of the

Giampiero Mancinelli

We present measurements of branching fractions and CP asymmetries of several B- -> D(*)0 K(*)- decays, with the D(*)0 decaying to CP-even, CP-odd, and flavor eigenstates, that can constrain the CP angle gamma as well as the amplitude ratio rb=A(B -> u)/A(B -> c), using methods proposed by Gronau, London and Wyler or Atwood, Dunietz and Sony. We use data coll

M. Lenti

Some Kaons and Hyperons rare decays branching ratios and form factors were measured by the NA48 experiment at CERN. The details of the measurements and their importance for the understanding of the CKM quark mixing matrix are discussed.

Caroline Riedl

Final HERMES results on the proton, deuteron and neutron structure function g1 are presented in the kinematic range 0.0021<x<0.9 and 0.1<Q2<20 GeV2. These results base on a refined analysis and are corrected for radiative and detector smearing effects using an unfolding algorithm. Furthermore, preliminary results on the first measurement of the tensor asymme

V. Buescher

With almost 0.5fb-1 of ppbar-collisions delivered in Tevatron Run II, both experiments CDF and D0 are reporting first results from a vast number of search analyses. This article summarizes the current status of Tevatron searches for Higgs bosons within the Standard Model and its extensions as well as direct searches for supersymmetric particles. Signatures f

A. Boyarsky, A. Neronov, I. Tkachev

We canonically quantize the dynamics of the brane universe embedded into the five-dimensional Schwarzschild-anti-deSitter bulk space-time. We show that in the brane-world settings the formulation of the quantum cosmology, including the problem of initial conditions, is conceptually more simple than in the 3+1-dimensional case. The Wheeler-deWitt equation is

Bianca Dittrich, Thomas Thiemann

This is the final fifth paper in our series of five in which we test the Master Constraint Programme for solving the Hamiltonian constraint in Loop Quantum Gravity. Here we consider interacting quantum field theories, specificlly we consider the non -- Abelean Gauss constraints of Einstein -- Yang -- Mills theory and 2+1 gravity. Interestingly, while Yang --

Bianca Dittrich, Thomas Thiemann

This is the fourth paper in our series of five in which we test the Master Constraint Programme for solving the Hamiltonian constraint in Loop Quantum Gravity. We now move on to free field theories with constraints, namely Maxwell theory and linearized gravity. Since the Master constraint involves squares of constraint operator valued distributions, one has

Bianca Dittrich, Thomas Thiemann

This is the third paper in our series of five in which we test the Master Constraint Programme for solving the Hamiltonian constraint in Loop Quantum Gravity. In this work we analyze models which, despite the fact that the phase space is finite dimensional, are much more complicated than in the second paper: These are systems with an $SL(2,\Rl)$ gauge symmet

Bianca Dittrich, Thomas Thiemann

This is the second paper in our series of five in which we test the Master Constraint Programme for solving the Hamiltonian constraint in Loop Quantum Gravity. In this work we begin with the simplest examples: Finite dimensional models with a finite number of first or second class constraints, Abelean or non -- Abelean, with or without structure functions.

Bianca Dittrich, Thomas Thiemann

Recently the Master Constraint Programme for Loop Quantum Gravity (LQG) was proposed as a classically equivalent way to impose the infinite number of Wheeler -- DeWitt constraint equations in terms of a single Master Equation. While the proposal has some promising abstract features, it was until now barely tested in known models. In this series of five paper

Miguel Alcubierre, Bernd Bruegmann, Peter Diener, Frank Herrmann

We perform both distorted black hole evolutions and binary black hole head on collisions and compare the results of using a full grid to results obtained by excising the black hole interiors. In both cases the evolutions are found to run essentially indefinitely, and produce the same, convergent waveforms. Further, since both the distorted black holes and th

Nathalie Deruelle, Yoshiyuki Morisawa

We compute the mass and angular momenta of rotating anti-de Sitter spacetimes in Einstein-Gauss-Bonnet theory of gravity using a superpotential derived from standard Noether identities. The calculation relies on the fact that the Einstein and Einstein-Gauss-Bonnet vacuum equations are the same when linearized on maximally symmetric backgrounds and uses the r

Hector Calderon, William A. Hiscock

The effects of quantized conformally invariant massless fields on the evolution of cosmological models containing a ``Big Rip&#39;&#39; future expansion singularity are examined. Quantized scalar, spinor, and vector fields are found to strengthen the accelerating expansion of such models as they approach the expansion singularity.

S. B. P. Wickramasuriya, V. Joseph, K. I. S. Karunaratne

We take a three dimensional Euclidian metric in toroidal coordinates and consider the corresponding Laplace equation. The simplest solution of this equation is taken. Based on this we build a Weyl space-time. This space-time is transformed to cylindrical coordinates. It is shown by using Mathematica that Weyl equations in cylindrical coordinates are satisfie

Amos Lapidoth

We obtain the first term in the high signal-to-noise ratio (SNR) expansion of the capacity of fading networks where the transmitters and receivers--while fully cognizant of the fading \emph{law}--have no access to the fading \emph{realization}. This term is an integer multiple of $\log \log \textnormal{SNR}$ with the coefficient having a simple combinatorial

Nathan LaBelle, Eugene Wallingford

This research analyzes complex networks in open-source software at the inter-package level, where package dependencies often span across projects and between development groups. We review complex networks identified at ``lower&#39;&#39; levels of abstraction, and then formulate a description of interacting software components at the package level, a relative

A. J. Millis, D. K. Morr, J. Schmalian

In a recent paper Castro-Neto and Jones argue that because the observability of quantum Griffiths-McCoy effects in metals is controlled by non-universal quantities, the quantum Griffiths-McCoy scenario may be a viable explanation for the non-fermi-liquid behavior observed in heavy fermion compounds. In this Comment we point out that the important non-univers

Young C. Kim, Michael E. Fisher

A novel algorithm is presented that yields precise estimates of coexisting liquid and gas densities, $ρ^{\pm}(T)$, from grand canonical Monte Carlo simulations of model fluids near criticality. The algorithm utilizes data for the isothermal minima of the moment ratio $Q_{L}(T;<ρ>_{L})$ $\equiv< m^{2}>_{L}^{2}/< m^{4}>_{L}$ in $L$$ \times$$ ...$$ \times$$ L$

J. L. Truitt, K. A. Slinker, K. L. M. Lewis, D. E. Savage

The mechanisms limiting the spin coherence time of electrons are of great importance for spintronics. We present electron spin resonance (ESR) and transport measurements of six different two dimensional electron gases in silicon/silicon-germanium (Si/SiGe 2DEGs). The spin decoherence time $T_2^*$ is presented in conjunction with the 2DEG density $n_e$ and mo

Giorgio Parisi, Tommaso Rizzo

We study the SUSY-breaking complexity of the Bethe Lattice Spin-Glass in the zero temperature limit. We consider both the Gaussian and the bimodal distribution of the coupling constants. For $J_{ij}=\pm 1$ the SUSY breaking theory yields fields distributions that concentrate on integer values at low temperatures, at variance with the unbroken SUSY theory. Th

Sang-Hyuk Lee, Kosta Ladavac, Marco Polin, David G. Grier

We demonstrate that a cycle of three holographic optical trapping patterns can implement a thermal ratchet for diffusing colloidal spheres, and that the ratchet-driven transport displays flux reversal as a function of the cycle frequency and the inter-trap separation. Unlike previously described ratchet models, the approach we describe involves three equival

Stefano Luin, Vittorio Pellegrini, Aron Pinczuk, Brian S. Dennis

The Hartree-Fock paradigm of bilayer quantum Hall states with finite tunneling at filling factor $ν$=1 has full pseudospin ferromagnetic order with all the electrons in the lowest symmetric Landau level. Inelastic light scattering measurements of low energy spin excitations reveal major departures from the paradigm at relatively large tunneling gaps. The res

F. Fischer, M. Grayson, D. Schuh, M. Bichler

We implement metallic layers of Si-doped (110) GaAs as modulation doping in high mobility p-type heterostructures, changing to p-growth conditions for the doping layer alone. The strongly auto-compensated doping is first characterized in bulk samples, identifying the metal-insulator transition density and confirming classic hopping conduction in the insulati

Luca De Sanctis

We extend to the random K-SAT and p-XOR-SAT optimization problems the results obtained for the Viana-Bray model of diluted mean field spin glass.

R. L. C. Vink, J. Horbach, K. Binder

The structure and the statistical fluctuations of interfaces between coexisting phases in the Asakura-Oosawa (AO) model for a colloid--polymer mixture are analyzed by extensive Monte Carlo simulations. We make use of a recently developed grand canonical cluster move with an additional constraint stabilizing the existence of two interfaces in the (rectangular

Frithjof B. Anders, G. Czycholl

The f-electron spectral function of the Falicov-Kimball model is calculated within the dynamical mean-field theory using the numerical renormalization group method as the impurity solver. Both the Bethe lattice and the hypercubic lattice are considered at half filling. For small U we obtain a single-peaked f-electron spectral function, which --for zero tempe

Jose Coelho, Gilles Patriarche, Frank Glas, Guillaume Saint-Girons

We account for lateral orderings of III-V nanostructures resulting from a GaAs/InAs/InGaAs/GaAs sequence grown on GaAs by metallorganic vapour phase epitaxy at two different temperatures. For both samples, the ordering is induced by the stress field of a periodic dislocation network (DN) shallowly buried and parallel to the surface. This DN is a grain bounda

D. Di Castro, R. Khasanov, C. Grimaldi, J. Karpinski

A study of the pressure effect on the magnetic penetration depth $λ$ in polycrystalline MgB$_{2}$ was performed by measuring the temperature dependence of the magnetization under an applied pressure of 0.15 and 1.13 GPa. We found that $λ^{-2}$ at low temperature is only slightly affected by pressure [$\frac{Δλ^{-2}}{λ^{-2}} = 1.5(9)%$], in contrast to cuprat

P. M. Dinh, P. -G. Reinhard, E. Suraud

We explore from a theoretical point of view pump and probe (P&P) analysis for fission of metal clusters where probe pulses are generalized to allow for scanning various frequencies. We show that it is possible to measure the time the system needs to develop to scission. This is achieved by a proper choice of both delay and frequency of the probe pulse. A mor

Jose Coelho, Gilles Patriarche, Frank Glas, Guillaume Saint-Girons

We first report a detailed transmission electron microscopy study of dislocation networks (DNs) formed at shallowly buried interfaces obtained by bonding two GaAs crystals between which we establish in a controlled manner a twist and a tilt around a k110l direction. For large enough twists, the DN consists of a twodimensional network of screw dislocations ac

A. Pautrat, J. Scola, Ch. Simon, P. Mathieu

Flux Lines Lattice (FLL) states have been studied using transport measurements and Small Angle Neutron Scattering in low T$_c$ materials. In Pb-In, the bulk dislocations in the FLL do not influence the transport properties. In Fe doped NbSe$_{2}$, transport properties can differ after a Field Cooling (FC) or a Zero Field Cooling (ZFC) procedure, as previousl

H. Iwasawa, T. Saitoh, Y. Yamashita, D. Ishii

We have investigated the electronic structure of polycrystalline Ca$_2$FeReO$_6$ using photoemission spectroscopy and band-structure calculations within the local-density approximation+$U$ (LDA+$U$) scheme. In valence-band photoemission spectra, a double-peak structure which is characteristic of the metallic double perovskite series has been observed near th

Shun-ichiro Koh

An abrupt drop in the moment of inertia recently found in solid helium 4 is explained in terms of dynamics of zero-point vacancies (ZPV). Mechanical decoupling of ZPV from the motion of the container due to Bose statistics is developed to a macroscopic phenomenon by repulsive interaction. It gives a negative answer to the question whether BEC is a necessary

Tsutomu Watanabe, Hisatoshi Yokoyama, Yukio Tanaka, Jun-ichiro Inoue

With the insulating phase of κ-(BEDT-TTF)_2X in mind, we study a t-J model on an anisotropic triangular lattice, where the hopping integral is t&#39; in one of the three directions, using a variational Monte Carlo method. By changing the value of t&#39;/t, we study the stability of superconducting (SC) states with d- and d+id-wave symmetries and of an antife

Xiao Liu, T. H. Metcalf, P. Mosaner, A. Miotello

We have studied the internal friction and the relative change in the speed of sound of amorphous diamond-like carbon films prepared by pulsed-laser deposition from 0.3 K to room temperature. Like the most of amorphous solids, the internal friction below 10 K exhibits a temperature independent plateau. The values of the internal friction plateau, however, are

Gunnar Pruessner, Ole Peters

We investigate a suggested path to self-organized criticality. Originally, this path was devised to &#34;generate criticality&#34; in systems displaying an absorbing-state phase transition, but closer examination of the mechanism reveals that it can be used for any continuous phase transition. We used the Ising model as well as the Manna model to demonstrate