September 2007 arXiv papers — page 42

Ketan D. Mulmuley

This article describes a {\em nonstandard} quantum group that may be used to derive a positive formula for the plethysm problem, just as the standard (Drinfeld-Jimbo) quantum group can be used to derive the positive Littlewood-Richardson rule for arbitrary complex semisimple Lie groups. The sequel \cite{GCT8} gives conjecturally correct algorithms to constru

Huichao Song, Ulrich W. Heinz

We compute the time evolution of elliptic flow in non-central relativistic heavy-ion collisions, using a (2+1)-dimensional code with longitudinal boost-invariance to simulate viscous fluid dynamics in the causal Israel-Stewart formulation. We show that even ``minimal'' shear viscosity eta/s=hbar/(4pi) leads to a large reduction of elliptic flow compa

J. Oelgoetz, C. J. Fontes, H. L. Zhang, M. Montenegro

It is shown that above the temperature of maximum abundance, recombination rates into the excited states of He-like ions that are calculated using earlier, more approximate methods differ markedly from rates obtained from recent distorted-wave and R-Matrix calculations (unified recombination rate coefficients) for Ca, Fe, and Ni. The present rates lead to G

Hugue Blier, Alain Tapp

In this article we introduce a new complexity class called PQMA_log(2). Informally, this is the class of languages for which membership has a logarithmic-size quantum proof with perfect completeness and soundness which is polynomially close to 1 in a context where the verifier is provided a proof with two unentangled parts. We then show that PQMA_log(2) = NP

K. J. H. Law, P. G. Kevrekidis, D. J. Frantzeskakis, A. R. Bishop

Motivated by recent work on instabilities in expanding domains in reaction-diffusion settings, we propose an analog of such mechanisms in energy-conserving wave equations. In particular, we consider a nonlinear Schr{ö}dinger equation in a finite domain and show how the expansion or contraction of the domain, under appropriate conditions, can destabilize its

Dirk Grupe, Stefanie Komossa, Luigi Gallo

We report the discovery of the Narrow-Line Seyfert 1 galaxy Mkn 335 in an extremely low X-ray state. A comparison of Swift observations obtained in May and June/July 2007 with all previous X-ray observations between 1971 to 2006 show the AGN to have diminished in flux by a factor of more than 30, the lowest X-ray flux Mkn 335 has ever been observed in. The S

Stefanos Papanikolaou, Kumar S. Raman, Eduardo Fradkin

We elucidate the topological features of the entanglement entropy of a region in two dimensional quantum systems in a topological phase with a finite correlation length $ξ$. Firstly, we suggest that simpler reduced quantities, related to the von Neumann entropy, could be defined to compute the topological entropy. We use our methods to compute the entangleme

Eugene M. Chudnovsky

An extension of Drude model is proposed that accounts for spin and spin-orbit interaction of charge carriers. Spin currents appear due to combined action of the external electric field, crystal field and scattering of charge carriers. The expression for spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mech

A. R. Champagne, J. P. Eisenstein, L. N. Pfeiffer, K. W. West

We study the Josephson-like interlayer tunneling signature of the strongly correlated $ν_T = 1$ quantum Hall phase in bilayer two-dimensional electron systems as a function of the layer separation, temperature and interlayer charge imbalance. Our results offer strong evidence that a finite temperature phase transition separates the interlayer coherent phase

M. H. S. Amin

We present a perturbative method to estimate the spectral gap for adiabatic quantum optimization, based on the structure of the energy levels in the problem Hamiltonian. We show that for problems that have exponentially large number of local minima close to the global minimum, the gap becomes exponentially small making the computation time exponentially long

Alessandro D'Adda, Issaku Kanamori, Noboru Kawamoto, Kazuhiro Nagata

A lattice formulation of a three dimensional super Yang-Mills model with a twisted N=4 supersymmetry is proposed. The extended supersymmetry algebra of all eight supercharges is fully and exactly realized on the lattice with a modified "Leibniz rule". The formulation we employ here is a three dimensional extension of the manifestly gauge covariant me

Dan Pirjol, Carlos Schat

We study the excited baryon states for an arbitrary number of colors Nc from the perspective of the permutation group S_N of N objects. Classifying the transformation properties of states and quark-quark interaction operators under S_N allows a general analysis of the spin-flavor structure of the mass operator of these states, in terms of a few unknown const

R. Roiban, A. A. Tseytlin

We consider the world surface in AdS_5 that ends on two intersecting null lines at the boundary. The corresponding string partition function describes the expectation value of the Wilson line with a null cusp in dual large N maximally supersymmetric gauge theory and thus determines the cusp anomaly function f(λ) of the gauge coupling. The first two coefficie

Melvyn B. Nathanson

Let F(x_1,...,x_m) = u_1 x_1 + ... + u_m x_m be a linear form with nonzero, relatively prime integer coefficients u_1,..., u_m. For any set A of integers, let F(A) = {F(a_1,...,a_m) : a_i in A for i=1,...,m}. The representation function associated with the form F is R_{A,F}(n) = card {(a_1,...,a_m) in A^m: F(a_1,..., a_m) = n}. The set A is a basis with resp

Luis Anchordoqui, Haim Goldberg

Interest has been directed recently towards low energy implications of a non-trivial conformal sector of an effective field theory with an IR fixed point (Λ), manifest in terms of ``unparticles'' with bizarre properties. We re-examine the implications of the limits on decay lifetimes of solar neutrinos for unparticle interactions. We study in detail

Abraham Broer, Jianjun Chuai

Let the finite group $G$ act linearly on the vector space $V$ over the field $k$ of arbitrary characteristic. If $H<G$ is a subgroup the extension of invariant rings $k[V]^G\subset k[V]^H$ is studied using modules of covariants. An example of our results is the following. Let $W$ be the subgroup of $G$ generated by the reflections in $G$. A classical theorem

Edward Taylor, Hui Hu, Xia-Ji Liu, Allan Griffin

We develop a variational approach to calculate the density response function at finite temperatures of the lowest-lying two-fluid modes in a trapped two-component Fermi superfluid close to a Feshbach resonance. The out-of-phase oscillations, which are the analogue in trapped gases of second sound in uniform superfluids, have so far not been observed in cold-

H. Mohseni Sadjadi

The coupling between Ricci scalar curvature and the baryon number current dynamically breaks CPT in an expanding universe and leads to baryon asymmetry. We study the effect of time dependence of equation of state parameter of the FRW universe on this asymmetry.

José M M. Senovilla

A reformulation of the Hoop Conjecture based on the concept of trapped circle is presented. The problems of severe compactness in every spatial direction, and of how to superpose the hoops with the surface of the black hole, are resolved. A new conjecture concerning &#34;peeling&#34; properties of dynamical/trapping horizons is propounded. A novel geometric

Miloslav Svec

Unitary evolution from pure initial states to pure final states in pi(-)p-> pi(-)pi(+)n imposes constraints on pion production amplitudes that are violated by CERN data on polarized target at 17.2 GeV/c. The pion creation is a non-unitary process arising from a unitary co-evolution of the pion creation process with a quantum environment. The purpose of this

Peter M. Brown

Within the past fifteen years the use of the concept of &#34;relativistic mass&#34; has been on the decline and has been replaced by the concept of &#34;proper mass&#34; (aka &#34;rest mass&#34;) - ?simply referred to as &#34;mass&#34; and labeled &#34;m&#34; by its proponents. This decline in usage appears to be due to arguments presented in several journal

Stefan Antusch, Steve F. King

We consider charged Lepton Flavour Violation (LFV) in the Constrained Minimal Supersymmetric Standard Model, extended to include the see-saw mechanism with Constrained Sequential Dominance (CSD), where CSD provides a natural see-saw explanation of tri-bimaximal neutrino mixing. When charged lepton corrections to tri-bimaximal neutrino mixing are included, we

Jonathan Sondow, Kyle Schalm

This is an expanded version of our earlier paper. Let the $n$th partial sum of the Taylor series $e = \sum_{r=0}^{\infty} 1/r!$ be $A_n/n!$, and let $p_k/q_k$ be the $k$th convergent of the simple continued fraction for $e$. Using a recent measure of irrationality for $e$, we prove weak versions of our conjecture that only two of the partial sums are converg

K. P. Unnikrishnan, Debprakash Patnaik, P. S. Sastry

Discovering the &#39;Neural Code&#39; from multi-neuronal spike trains is an important task in neuroscience. For such an analysis, it is important to unearth interesting regularities in the spiking patterns. In this report, we present an efficient method for automatically discovering synchrony, synfire chains, and more general sequences of neuronal firings.

Tommy Burch, Christian Ehmann, Christian Hagen, Martin Hetzenegger

We present results for masses of excited mesons from dynamical clover-Wilson lattices provided by the CP-PACS collaboration at pion masses down to 500 MeV. Our analysis of the data is based on using a matrix of correlators from various source and sink operators. The spectroscopy results are discussed and compared to experimental values.

Arthur Baragar, David McKinnon

We prove that for any of a wide class of elliptic surfaces $X$ defined over a number field $k$, if there is an algebraic point on $X$ that lies on only finitely many rational curves, then there is an algebraic point on $X$ that lies on no rational curves. In particular, our theorem applies to a large class of elliptic $K3$ surfaces, which relates to a questi

M. Glück, P. Jimenez-Delgado, E. Reya

Utilizing recent DIS measurements (F_{2,L}) and data on dilepton and high-E_{T} jet production we determine the dynamical parton distributions of the nucleon generated radiatively from valence-like positive input distributions at optimally chosen low resolution scales. These are compared with `standard&#39; distributions generated from positive input distrib

V. Ferrari, L. Gualtieri

We review the main results obtained in the literature on quasi-normal modes of compact stars and black holes, in the light of recent exciting developments of gravitational wave detectors. Quasi-normal modes are a fundamental feature of the gravitational signal emitted by compact objects in many astrophysical processes; we will show that their eigenfrequencie

Andre Eckardt, Martin Holthaus

We argue that a system of ultracold bosonic atoms in a tilted optical lattice can become superfluid in response to resonant AC forcing. Among others, this allows one to prepare a Bose-Einstein condensate in a state associated with a negative effective mass. Our reasoning is backed by both exact numerical simulations for systems consisting of few particles, a

P. L. Iafelice, G. P. Vacca

Even within the framework of the leading logarithmic approximation the eigenvalues of the BKP kernel for states of more than three reggeized gluons are unknown in general, contrary to the planar limit case where the problem becomes integrable. We consider a 4-gluon kernel for a finite number of colors and define some simple toy models for the configuration s

Daniele Bettinelli, Ruggero Ferrari, Andrea Quadri

In this paper we evaluate the self-energy of the vector mesons at one loop in our recently proposed subtraction scheme for massive nonlinearly realized SU(2) Yang-Mills theory. We check the fulfillment of physical unitarity. The resulting self-mass can be compared with the value obtained in the massive Yang-Mills theory based on the Higgs mechanism, consisti

Raquel Diaz, Inkang Kim

In this paper we study the convergence behavior of grafting rays to the Thurston boundary of Teichmuller space. When the grafting is done along a weighted system of simple closed curves or along a maximal uniquely ergodic lamination this behavior is the same as for Teichmuller geodesics and lines of minima. We also show that the ray grafted along a weighted

Andrea Ferrario

We derive the explicit form of the superpropagators in presence of general boundary conditions (coisotropic branes) for the Poisson Sigma Model. This generalizes the results presented in Cattaneo and Felder&#39;s previous works for the Kontsevich angle function used in the deformation quantization program of Poisson manifolds without branes or with at most t

Igal Sason

This paper is focused on the derivation of some universal properties of capacity-approaching low-density parity-check (LDPC) code ensembles whose transmission takes place over memoryless binary-input output-symmetric (MBIOS) channels. Properties of the degree distributions, graphical complexity and the number of fundamental cycles in the bipartite graphs are

Kateryna Mishchenko, Sverker Holmgren, Lars Ronnegard

Regions in the genome that affect complex traits, quantitative trait loci (QTL), can be identified using statistical analysis of genetic and phenotypic data. When restricted maximum-likelihood (REML) models are used, the mapping procedure is normally computationally demanding. We develop a new efficient computational scheme for QTL mapping using variance com

M. Bonura, A. Agliolo Gallitto, M. Li Vigni, C. Ferdeghini

We report on the microwave surface resistance of two polycrystalline Mg11B2 samples; one consists of pristine material, the other has been irradiated at very high neutron fluence. It has already been reported that in the strongly irradiated sample the two gaps merge into a single value. The mw surface resistance has been measured in the linear regime as a fu

Shizeng Lin, Xiao Hu, Masashi Tachiki

Solving coupled nonlinear sine-Gordon equations and Maxwell equations numerically, we study the electromagnetic and superconducting properties of the single crystal of high-$T_c$ superconductor $\rm{Bi_2Sr_2CaCu_2O_{8+δ}}$ with a static magnetic field applied parallel to the $ab$-plane and a dc current fed in along the c-axis. Cavity resonances of transverse

K. -P. Marzlin, B. C. Sanders, P. L. Knight

We establish a rigorous quantitative connection between (i) the interferometric duality relation for which-way information and fringe visibility and (ii) Heisenberg&#39;s uncertainty relation for position and modular momentum. We apply our theory to atom interferometry, wherein spontaneously emitted photons provide which way information, and unambiguously re

Paul Gough

Landauer&#39;s principle is applied to information in the universe. Once stars began forming, the increasing proportion of matter at high stellar temperatures compensated for the expanding universe to provide a near constant information energy density. The information equation of state was close to the dark energy value, w = -1, for a wide range of redshifts

T. Fujita, M. B. A. Jalil, S. G. Tan

We describe an intrinsic spin-Hall effect in $n$-type bulk zinc-blende semiconductors with topological origin. When electron transport is confined to a waveguide structure, and the applied electric field is such that the spins of electrons remain as eigenstates of the Dresselhaus spin-orbit field with negligible subband mixing, a gauge structure appears in t

Craig J. Hogan

A brief survey is presented of new science that will emerge during the decades ahead from direct detection of gravitational radiation. Interferometers on earth and in space will probe the universe in an entirely new way by directly sensing motions of distant matter over a range of more than a million in frequency. The most powerful sources of gravitational (

Sanjay Kumar, Garima Mishra

A model of self avoiding walks with suitable constraint has been developed to study the effect of temperature on a single stranded DNA (ssDNA) in the constant force ensemble. Our exact calculations for small chains show that the extension (reaction co-ordinate) may increase or decrease with the temperature depending upon the applied force. The simple model d

J. G. Mangum, D. T. Emerson, E. W. Greisen

The On-The-Fly (OTF) imaging technique enables single-dish radio telescopes to construct images of small areas of the sky with greater efficiency and accuracy. This paper describes the practical application of the OTF imaging technique. By way of example the implementation of the OTF imaging technique at the NRAO 12 Meter Telescope is described. Specific req

Andrzej Kupsc

An introduction to the physics of eta and eta&#39; meson decays is given. A historical account of the discovery of the mesons is presented. It is followed by an overview and classification of the common decay modes and the relevance of the mesons for modern hadron and particle physics. In more detail the hadronic decay modes are discussed and in particular s

Yusuke Sasano

In this note, we review the notion of Painlevé scheme of the sixth Painlevé equation from the viewpoint of accessible singular point and its local index in the Hirzebruch surface of degree two ${Σ_2}$. The key method is Painlevé $α$-method for each accessible singular point. Giving a Painlevé scheme in the differential system satisfying certain conditions, w

Shao-Hsuan Chiu

This paper has been withdrawn by the author, due to errors in the figures.

N. Lambert, I. Mahboob, M. Pioro-Ladrière, Y. Tokura

Magnetically coupling a nano-mechanical resonator to a double quantum dot confining two electrons can enable the manipulation of a single electron spin and the readout of the resonator&#39;s natural frequency. When the Larmor frequency matches the resonator frequency, the electron spin in one of the dots can be selectively flipped by the magnetised resonator

S. Pasini, T. Fischer, P. Karbach, G. S. Uhrig

The coherent control of small quantum system is considered. For a two-level system coupled to an arbitrary bath we consider a pulse of finite duration. We derive the leading and the next-leading order corrections to the evolution operator due to the non-commutation of the pulse and the bath Hamiltonian. The conditions are computed that make the leading corre

M. N. Chernodub, Antti J. Niemi

We argue that a version of the four dimensional Brans-Dicke theory can be embedded in the standard flat spacetime electroweak theory. The embedding involves a change of variables that separates the isospin from the hypercharge in the electroweak theory.

Wontae Kim, John J. Oh

We derive the formula of the black hole entropy with a minimal length of the Planck size by counting quantum modes of scalar fields in the vicinity of the black hole horizon, taking into account the generalized uncertainty principle (GUP). This formula is applied to some intriguing examples of black holes - the Schwarzschild black hole, the Reissner-Nordstro

Pierre Gosselin, Alain Berard, Herve Mohrbach, Subir Ghosh

We consider the Doubly Special Relativity (DSR) generalization of Dirac equation in an external potential in the Magueijo-Smolin base. The particles obey a modified energy-momentum dispersion relation. The semiclassical diagonalization of the Dirac Hamiltonian reveals the intrinsic Berry phase effects in the particle dynamics.

Jan Harm van der Walt

This paper deals with the solution of large classes of systems of nonlinear partial differential equations (PDEs) in spaces of generalized functions that are constructed as the completion of uniform convergence spaces. The existence result for the mentioned systems of equations are obtained as an application of a basic approximation result, which is formulat

Tomohiro Matsuda

We consider inhomogeneous preheating in multi-field models of cosmological perturbation. After preheating, two fields are trapped at an enhanced symmetric point. One field is an oscillating field and the other is a light field that plays an important role in generating perturbation. In this presentation, we consider two types of potential for the light field

Andreas Karch, Andy O&#39;Bannon

We use the AdS/CFT correspondence to study the thermodynamics of massive N=2 supersymmetric hypermultiplets coupled to N=4 supersymmetric SU(Nc) Yang-Mills theory in the limits of large Nc and large &#39;t Hooft coupling. In particular, we study the theory at finite baryon number density. At zero temperature, we present an exact expression for the hypermulti

P. S. Bourdon, E. Gerjuoy, J. P. McDonald, H. T. Williams

We present an analytical study of the standard two-party deterministic dense-coding protocol, under which communication of perfectly distinguishable messages takes place via a qudit from a pair of non-maximally entangled qudits in pure state |S>. Our results include the following: (i) We prove that it is possible for a state |S> with lower entanglement entro

Akira SaiToh, Robabeh Rahimi, Mikio Nakahara

Quantum coherence conservation is shown to be achieved by a very high rate of dissipation of an environmental system coupled with a principal system. This effect is not in the list of previously-known strategies of noise suppression, such as Zeno effect, dynamical decoupling, quantum error correction code, and decoherence free subspace. An analytical solutio

Leonard A. Harris, Aaron M. Piccirilli, Emily R. Majusiak, Paulette Clancy

&#34;Leaping&#34; methods show great promise for significantly accelerating stochastic simulations of complex biochemical reaction networks. However, few practical applications of leaping have appeared in the literature to date. Here, we address this issue using the &#34;partitioned leaping algorithm&#34; (PLA) [L.A. Harris and P. Clancy, J. Chem. Phys. 125,

Hans Christianson

We consider solutions to the linear wave equation on non-compact Riemannian manifolds without boundary when the geodesic flow admits a filamentary hyperbolic trapped set. We obtain a polynomial rate of local energy decay with exponent depending only on the dimension.

A. Beresnyak, A. Lazarian

We consider stationary, forced, imbalanced, or cross-helical MHD Alfvenic turbulence where the waves traveling in one direction have higher amplitudes than the opposite waves. This paper is dedicated to so-called strong turbulence, which cannot be treated perturbatively. Our main result is that the anisotropy of the weak waves is stronger than the anisotropy

Yuri Bonder, Daniel Sudarsky

We describe a scheme for the exploration of quantum gravity phenomenology focussing on effects that could be thought as arising from a fundamental granularity of space-time. In contrast with the simplest assumptions, such granularity is assumed to respect Lorentz Invariance but is otherwise left unspecified. The proposal is fully observer covariant, it invol

Eugene Z. Xia

The pure braid group Γof a quadruply-punctured Riemann sphere acts on the SL(2,C)-moduli M of the representation variety of such sphere. The points in M are classified into Γ-orbits. We show that, in this case, the monodromy groups of many explicit solutions to the Riemann-Hilbert problem are subgroups of SU(2). Most of these solutions are examples of repres

Ibrahim Assem, Thomas Bruestle, Ralf Schiffler

We study the module category of a certain Galois covering of a cluster-tilted algebra which we call the cluster repetitive algebra. Our main result compares the module categories of the cluster repetitive algebra of a tilted algebra C and the repetitive algebra of C, in the sense of Hughes and Waschbuesch.

Ketan D. Mulmuley

Geometric complexity theory (GCT) is an approach to the $P$ vs. $NP$ and related problems through algebraic geometry and representation theory. This article gives a high-level exposition of the basic plan of GCT based on the principle, called the flip, without assuming any background in algebraic geometry or representation theory.

Wenliang Zhang

Let $X$ be an arbitrary projective scheme over a field $k$. Let $A$ be the local ring at the vertex of the affine cone for some embedding $ι: X\hookrightarrow \mathbb{P}^n_k$. G. Lyubeznik asked (in \cite{l2}) whether the integers $λ_{i,j}(A)$ (defined in \cite{l1}), called the Lyubeznik numbers of $A$, depend only on $X$, but not on the embedding. In this p

Ketan D. Mulmuley, Milind Sohoni

These are lectures notes for the introductory graduate courses on geometric complexity theory (GCT) in the computer science department, the university of Chicago. Part I consists of the lecture notes for the course given by the first author in the spring quarter, 2007. It gives introduction to the basic structure of GCT. Part II consists of the lecture notes

B. Botchev, G. Finocchiaro, J. Hoffman, R. L. McCarthy

The purpose, design specifications, construction techniques, and testing methods are described for the high voltage feedthrough ports and filters of the ATLAS Liquid Argon calorimeters. These feedthroughs carry about 5000 high voltage wires from a room-temperature environment (300 K) through the cryostat walls to the calorimeters cells (89 K) while maintaini

Karin Cvetko-Vah, Damjana Kokol Bukovšek, Tomaž Košir, Ganna Kudryavtseva

We classify minimal transitive subsemigroups of the finitary inverse symmetric semigroup modulo the classification of minimal transitive subgroups of finite symmetric groups; and semitransitive subsemigroups of the finite inverse symmetric semigroup of the minimal cardinality modulo the classification of transitive subgroups of the minimal cardinality of fin

Rod Gow, Rachel Quinlan

Let K be a field admitting a cyclic Galois extension of degree n. The main result of this paper is a decomposition theorem for the space of alternating bilinear forms defined on a vector space of odd dimension n over K. We show that this space of forms is the direct sum of (n-1)/2 subspaces, each of dimension n, and the non-zero elements in each subspace hav

Munshi G. Mustafa, Markus H. Thoma

The comments raised in Ref. [1] by Mishra et al aim at two papers contained in Ref. [2]. We show that those comments on Ref. [2] pointed out by Mishra et al in Ref.[1] are not relevant and the concept used in Ref.[2] is consistent and in compliance with the classical approximation of the transport coefficients [3]. We would also like to note that most of the

Paolo Lisca, Andras I. Stipsicz

We determine the closed, oriented Seifert fibered 3-manifolds which carry positive tight contact structures. Our main tool is a new non-vanishing criterion for the contact Ozsvath-Szabo invariant.

Luis A. Anchordoqui, Haim Goldberg, Dan Hooper, Subir Sarkar

The Pierre Auger Observatory (PAO) has measured the spectrum and composition of the ultrahigh energy cosmic rays with unprecedented precision. We use these measurements to constrain their spectrum and composition as injected from their sources and, in turn, use these results to estimate the spectrum of cosmogenic neutrinos generated in their propagation thro

D. Christopher Martin, Todd Small, David Schiminovich, Ted K. Wyder

We use a new stacking technique to obtain mean mid IR and far IR to far UV flux ratios over the rest near-UV/near-IR color-magnitude diagram. We employ COMBO-17 redshifts and COMBO-17 optical, GALEX far and near UV, Spitzer IRAC and MIPS Mid IR photometry. This technique permits us to probe infrared excess (IRX), the ratio of far IR to far UV luminosity, and

L. Alvarez-Ruso, L. S. Geng, S. Hirenzaki, M. J. Vicente Vacas

We have investigated the neutrino induced coherent pion production reaction at low and intermediate energies including pion, nucleon and Delta(1232) resonance. Medium effects in the production mechanism and the distortion of the pion wave function are included in the calculation. We find a strong reduction of the cross section due to these effects and also s

Anindya Das, A. K. Sood, A. Govindaraj, A. Marco Saitta

In-situ Raman experiments together with transport measurements have been carried out on carbon nanotubes as a function of gate voltage. In metallic tubes, a large increase in the Raman frequency of the $G^-$ band, accompanied by a substantial decrease of its line-width, is observed with electron or hole doping. In addition, we see an increase in Raman freque

Jan-Peter Boernsen, Anton E. M. van de Ven

We re-analyze a possible ambiguity in the application of dimensional regularization to Einstein-Gauss-Bonnet gravity, arising from the way one treats the Gauss-Bonnet term. It is demonstrated that the addition of such a term to the action gives rise to a non-minimal graviton wave operator, but does not produce new on shell divergences at one loop order in d=

Joel L. Lebowitz

Time-asymmetric behavior as embodied in the second law of thermodynamics is observed in {\it individual macroscopic} systems. It can be understood as arising naturally from time-symmetric microscopic laws when account is taken of a) the great disparity between microscopic and macroscopic scales, b) a low entropy state of the early universe, and c) the fact t

Lin Ma, William S. Klug

As two-dimensional fluid shells, lipid bilayer membranes resist bending and stretching but are unable to sustain shear stresses. This property gives membranes the ability to adopt dramatic shape changes. In this paper, a finite element model is developed to study static equilibrium mechanics of membranes. In particular, a viscous regularization method is pro

Yu Ding

We show that a rescale limit at any degenerate singularity of Ricci flow in dimension 3 is a steady gradient soliton. In particular, we give a geometric description of type I and type II singularities.

Adam Lowrance

To each knot $K\subset S^3$ one can associated its knot Floer homology $\hat{HFK}(K)$, a finitely generated bigraded abelian group. In general, the nonzero ranks of these homology groups lie on a finite number of slope one lines with respect to the bigrading. The width of the homology is, in essence, the largest horizontal distance between two such lines. Al

Alexander K. Vidybida

Recently, origins of non-deterministic behavior and free will in living systems obtain growing interest (see, e.g. Maye A, Hsieh C, Sugihara G, Brembs B (2007) Order in Spontaneous Behavior. PLoS ONE 2(5): e443. doi:10.1371/journal.pone.0000443). In this text, devoted to electromagnetic hypersensitivity, in n.2 and n.4, a possible physical mechanism of free

F. C. Khanna, J. M. C. Malbouisson, A. E. Santana, E. S. Santos

A class of squeezed boson and fermion states is studied with particular emphasis on the nature of entanglement. We first investigate the case of bosons, considering two-mode squeezed states. Then we construct the fermion version to show that such states are maximum entangled, for both bosons and fermions. To achieve these results, we demonstrate some relatio

Abraham Broer

Let $G$ be a finite group acting linearly on the vector space $V$ over a field of arbitrary characteristic. The action is called coregular if the invariant ring is generated by algebraically independent homogeneous invariants and the direct summand property holds if there is a surjective $k[V]^G$-linear map $π:k[V]\to k[V]^G$. The following Chevalley-Shephar

R. Wortis, Yun Song, W. A. Atkinson

With the goal of measuring localization in disordered interacting systems, we examine the finite-size scaling of the geometrically-averaged density of states calculated from the local Green&#39;s function with finite energy resolution. Our results show that, unlike in a simple energy binning procedure, there is no limit in which the finite energy resolution

Abraham Broer

Let $G$ be a finite group acting linearly on the vector space $V$ over a field of arbitrary characteristic. The action is called {\em coregular} if the invariant ring is generated by algebraically independent homogeneous invariants and the {\em direct summand property} holds if there is a surjective $k[V]^G$-linear map $π:k[V]\to k[V]^G$. The following Cheva

C. Quireza, H. J. Rocha-Pinto, W. J. Maciel

In this paper we present a re-analysis of the criteria used to characterize the Peimbert classes I, IIa, IIb, III and IV, through a statistical study of a large sample of planetary nebulae previously classified according to these groups. In the original classification, it is usual to find planetary nebulae that cannot be associated with a single type; these

Oded Schramm

The Andreev-Thurston Circle Packing Theorem is generalized to packings of convex bodies in planar simply connected domains. This turns out to be a useful tool for constructing conformal and quasiconformal mappings with interesting geometric properties. We attempt to illustrate this with a few results about uniformizations of finitely connected planar domains

M. Bell, A. Sergeev, V. Mitin, J. Bird

We investigate competition between one- and two-dimensional topological excitations - phase slips and vortices - in formation of resistive states in quasi-two-dimensional superconductors in a wide temperature range below the mean-field transition temperature $T_{C0}$. The widths $w$ = 100 nm of our ultrathin NbN samples is substantially larger than the Ginzb

E. Hernandez, J. Nieves, M. Valverde

We construct a model for the weak pion production off the nucleon, which in addition to the weak excitation of the $Δ(1232)$ resonance and its subsequent decay into $Nπ$, it includes also some background terms required by chiral symmetry. We re-fit the $C_5^A(q^2)$ form factor to the flux averaged $ν_μp \to μ^-pπ^+$ ANL $q^2-$differential cross section data,

Osman Güler, Filiz Gürtuna

A convex body K has associated with it a unique circumscribed ellipsoid CE(K) with minimum volume, and a unique inscribed ellipsoid IE(K) with maximum volume. We first give a unified, modern exposition of the basic theory of these extremal ellipsoids using the semi-infinite programming approach pioneered by Fritz John in his seminal 1948 paper. We then inves

M. E. Carrington, E. Kovalchuk

In this article we study the electrical conductivity in QED using the resummed 3PI effective action. We work to 3-loop order in the effective action. We show that the resulting expression for the conductivity is explicitly gauge invariant, and that the integral equations that resum the pinching and colinear contributions are produced naturally by the formali

CDF Collaboration, T. Aaltonen

We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb^{-1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific topcolor-as

H. Krawczynski, J. Buckley, K. Byrum, C. Dermer

In recent years, ground-based gamma-ray observatories have made a number of important astrophysical discoveries which have attracted the attention of the wider scientific community. The Division of Astrophysics of the American Physical Society has requested the preparation of a white paper on the status and future of ground-based gamma-ray astronomy to defin

D. O. Filonenko, D. L. Finkelshtein, Yu. G. Kondratiev

Properties of a contact process in continuum for a system of two type particles one type of which is independent are considered. We study dynamics of the first and second order correlation functions, their asymptotics and dependence on parameters of the system.

Anton Šurda

Statistical mechanics of a small system of cars on a single-lane road is developed. The system is not characterized by a Hamiltonian but by a conditional probability of a velocity of a car for the given velocity and distance of the car ahead. Distribution of car velocities for various densities of a group of cars are derived as well as probabilities of densi

Mario Bessa, Pedro Duarte

We consider a compact 3-dimensional boundaryless Riemannian manifold M and the set of divergence-free (or zero divergence) vector fields without singularities, then we prove that this set has a C1-residual such that any vector field inside it is Anosov or else its elliptical orbits are dense in the manifold M.

Saad Zaheer, Alejandro W. Rodriguez, Steven G. Johnson, Robert L. Jaffe

Using the ray-optics approximation, we analyze the Casimir force in a two dimensional domain formed by two metallic blocks adjacent to parallel metallic sidewalls, which are separated from the blocks by a finite distance h. For h > 0, the ray-optics approach is not exact because diffraction effects are neglected. Nevertheless, we show that ray optics is able

B. Detlefs, S. B. Wilkins, R. Caciuffo, J. A. Paixão

We report a resonant x-ray scattering (RXS) study of antiferromagnetic neptunium compounds NpCoGa_5 and NpRhGa_5 at the Np M_4 and Ga K-edges. Large resonant signals of magnetic dipole character are observed below the Neel temperatures at both edges. The signals at the Np edges confirm the behaviour determined previously from neutron diffraction, i.e. the mo

R. H. D. Townsend, S. P. Owocki, A. ud-Doula

We introduce a new Rigid-Field Hydrodynamics approach to modeling the magnetospheres of massive stars in the limit of very-strong magnetic fields. Treating the field lines as effectively rigid, we develop hydrodynamical equations describing the 1-dimensional flow along each, subject to pressure, radiative, gravitational, and centrifugal forces. We solve thes

Andreas Athenodorou, Barak Bringoltz, Michael Teper

We use lattice techniques to study the closed-string spectrum of SU(N) gauge theories in 2+1 dimensions. We calculate the energies of the lowest lying ~30 states for strings with lengths between l ~ 0.45 fm and l ~ 3 fm, and compare to different theoretical predictions. We obtain unambiguous evidence that the closed-strings are in the universality class of t

C. Grygiel, Ch. Simon, B. Mercey, W. Prellier

High quality vanadium sesquioxide V2O3 films (170-1100 Å) were grown using the pulsed laser deposition technique on (0001)-oriented sapphire substrates, and the effects of film thickness on the lattice strain and electronic properties were examined. X-ray diffraction indicates that there is an in-plane compressive lattice parameter (a), close to -3.5% with r