June 2006 arXiv papers — page 16

Deepa Kasinathan, K. Koepernik, J. Kunes, H. Rosner

In an attempt to provide a clearer understanding of the impressive increase in T_c under pressure in elemental Li, linear response calculation of the phonon dispersion curves, electron-phonon matrix elements, phonon linewidths and mode lambda's have been carried out on a finer mesh (24^3 in the Brillouin zone) than done previously, for the volume corresp

Reinhard Prix

We develop a general formalism for the parameter-space metric of the multi-detector F-statistic, which is a matched-filtering detection statistic for continuous gravitational waves. We find that there exists a whole family of F-statistic metrics, parametrized by the (unknown) amplitude parameters of the gravitational wave. The multi-detector metric is shown

A. Costescu, S. Spanulescu, C. Stoica

In this paper, the right expressions of the fully nonrelativistic K-shell Rayleigh scattering amplitudes and cross-sections are obtained by using the Coulomb Green function method. Our analytical result has no spurious poles as the old nonrelativistic result with retardation [M. Gavrila and A.Costescu Phys. Rev. A 2, 1752 (1970)] presents. Taking into accoun

A. Costescu, S. Spanulescu, C. Stoica

Considering the contributions of the main term of the relativistic Coulombian Green function given by Hostler [J. Math. Phys, 5, 591 (1964)] to the second order of the S-matrix element and taking into account only the large components of Dirac spinor of the 2S subshell, we have obtained the imaginary part of the Rayleigh amplitudes in terms of elementary fun

Jason X. Prochaska

We examine the practice of deriving interstellar medium (ISM) abundances from low-resolution spectroscopy of GRB afterglows. We argue that the multi-ion single-component curve-of-growth analysis technique systematically underestimates the column densities of the metal-line profiles commonly observed for GRB. This systematic underestimate is accentuated by th

A. Costescu, S. Spanulescu, C. Stoica

Considering the contributions of the main term of the relativistic Coulombian Green function given by Hostler to the second order of S matrix element and taking into account only the large components of the Dirac spinor of the ground state we obtain the imaginary part of the Rayleigh amplitudes in terms of elementary functions. Thereby simple and high accura

Hicham El-Bouanani, Michel Rouleux

We consider a 2-dimensional planar rotator on a large, but finite lattice with a ferromagnetic Kac potential $J_γ(i)=γ^2J(γi)$, $J$ with compact support. The system is subject to boundary conditions with vorticity. Using a Glauber like dynamics, we compute minimizers of the free energy functional at low temperature, i.e. in the regime of phase transition. We

J. Piedra, G. Gómez-Ceballos

The Tevatron collider at Fermilab provides a very rich environment for the study of b-hadrons. Both the D0 and CDF experiments have collected a sample of about 1 fb^{-1}. We report results on three topics: b-hadron lifetimes, polarization amplitudes and the decay width difference in Bs to Jpsi Phi, and Bs mixing.

Duiliu-Emanuel Diaconescu, Alberto Garcia-Raboso, Robert L. Karp, Kuver Sinha

We develop computational tools for the tree-level superpotential of B-branes in Calabi-Yau orientifolds. Our method is based on a systematic implementation of the orientifold projection in the geometric approach of Aspinwall and Katz. In the process we lay down some ground rules for orientifold projections in the derived category.

Vieri Mastropietro

The Adler-Bardeen theorem has been proved only as a statement valid at all orders in perturbation theory, without any control on the convergence of the series. In this paper we prove a nonperturbative version of the Adler-Bardeen theorem in $d=2$ by using recently developed technical tools in the theory of Grassmann integration.

D. J. Priour, S. Das Sarma

We consider ferromagnetism in spatially randomly located magnetic moments, as in a diluted magnetic semiconductor, coupled via the carrier-mediated indirect exchange RKKY interaction. We obtain via Monte Carlo the magnetic phase diagram as a function of the impurity moment density $n_{i}$ and the relative carrier concentration $n_{c}/n_{i}$. As evidenced by

Dimitris G. Angelakis, Marcelo F. Santos, Sougato Bose

As photons do not interact with each other, it is interesting to ask whether photonic systems can be modified to exhibit the phases characteristic of strongly coupled many-body systems. We demonstrate how a Mott insulator type of phase of excitations can arise in an array of coupled electromagnetic cavities, each of which is coupled resonantly to a {\em sing

Aristomenis Donos

In this paper we present an effort to extend the LLM construction of 1/2 BPS states in minimal IIB supergravity to configurations that preserve 1/4 of the total number of supersymmetries. Following the same techniques we reduce the problem to that of a single scalar which satisfies a non-linear equation. In particular, the scalar is identified to be the Kahl

James Conant, Karen Vogtmann

There is a series of cycles in the rational homology of the groups Out(F_n), first discovered by S. Morita, which have an elementary description in terms of finite graphs. The first two of these give nontrivial homology classes, and it is conjectured that they are all nontrivial. These cycles have natural lifts to the homology of Aut(F_n), which is stably tr

BL Feigin, AM Gainutdinov, AM Semikhatov, IYu Tipunin

We derive and study a quantum group g(p,q) that is Kazhdan--Lusztig-dual to the W-algebra W(p,q) of the logarithmic (p,q) conformal field theory model. The algebra W(p,q) is generated by two currents $W^+(z)$ and $W^-(z)$ of dimension (2p-1)(2q-1), and the energy--momentum tensor T(z). The two currents generate a vertex-operator ideal $R$ with the property t

D. B. McReynolds

In this article we verify an orbifold version of a conjecture of Nimershiem from 1998. Namely, for every flat $n$-manifold $M$, we show that the set of similarity classes of flat metrics on $M$ which occur as a cusp cross-section of a hyperbolic $(n+1)$-orbifold is dense in the space of similarity classes of flat metrics on $M$. The set used for density is p

BL Feigin, AM Gainutdinov, AM Semikhatov, IYu Tipunin

We study logarithmic conformal field models that extend the (p,q) Virasoro minimal models. For coprime positive integers $p$ and $q$, the model is defined as the kernel of the two minimal-model screening operators. We identify the field content, construct the W-algebra W(p,q) that is the model symmetry (the maximal local algebra in the kernel), describe its

Masaru Onoda, Shuichi Murakami, Naoto Nagaosa

We construct a semiclassical theory for propagation of an optical wavepacket in non-conducting media with periodic structures of dielectric permittivity and magnetic permeability, i.e., non-conducting photonic crystals. We employ a quantum-mechanical formalism in order to clarify its link to those of electronic systems. It involves the geometrical phase, i.e

Kris Krogh

"Wave gravity" refers to a quantum-mechanical gravity theory introduced in two previous papers [1,2]. Although based on the optics of de Broglie waves instead of curved space-time, it agrees with the standard tests of general relativity. As in that theory, galactic nuclei are dark objects where gravity prevents the escape of most radiation. In this c

Xavier Bekaert, Nicolas Boulanger

Quadratic, second-order, non-local actions for tensor gauge fields transforming in arbitrary irreducible representations of the general linear group in D-dimensional Minkowski space are explicitly written in a compact form by making use of Levi-Civita tensors. The field equations derived from these actions ensure the propagation of the correct massless physi

Seckin Kurkcuoglu, Christian Saemann

We give a simplified formula for the star product on CP^n_L, which enables us to define a twist element suited for discussing a Drinfeld twist like structure on fuzzy complex projective spaces. The existence of such a twist will have several consequences for field theories on fuzzy spaces, some of which we discuss in the present paper. As expected, we find t

Emma L. Allard, Johan H. Knapen, Reynier F. Peletier, Marc Sarzi

(Abridged) Star-forming nuclear rings in barred galaxies are common in nearby spirals, and their detailed study can lead to important insights into the evolution of galaxies, their bars, and their central regions. We present integral field spectroscopic observations obtained with SAURON of the bar and circumnuclear region of the barred spiral galaxy M100, co

Christian Ertler, Jaroslav Fabian

A three barrier resonant tunneling structure in which the two quantum wells are formed by a dilute magnetic semiconductor material (ZnMnSe) with a giant Zeeman splitting of the conduction band is theoretically investigated. Self-consistent numerical simulations of the structure predict giant magnetocurrent in the resonant bias regime as well as significant c

Kasper Peeters, Jacob Sonnenschein, Marija Zamaklar

We analyse mesons at finite temperature in a chiral, confining string dual. The temperature dependence of low-spin as well as high-spin meson masses is shown to exhibit a pattern familiar from the lattice. Furthermore, we find the dissociation temperature of mesons as a function of their spin, showing that at a fixed quark mass, mesons with larger spins diss

S. Sinel'shchikov, A. Stolin, L. Vaksman

This paper is devoted to study of differential calculi over quadratic algebras, which arise in the theory of quantum bounded symmetric domains. We prove that in the quantum case dimensions of the homogeneous components of the graded vector spaces of k-forms are the same as in the classical case. This result is well-known for quantum matrices. The quadratic a

M. Blagojevic, B. Cvetkovic

Asymptotic symmetry of the Euclidean 3D gravity with torsion is described by two independent Virasoro algebras with different central charges. Elements of this boundary conformal structure are combined with Cardy's formula to calculate the black hole entropy.

L. Maiani, A. D. Polosa, V. Riquer, C. A. Salgado

We consider the Nuclear Modification Ratios in heavy ion collisions, R_CP and R_AA, in the region of intermediate transverse momentum, and study the dependency upon the constituent quark composition of the observed hadron. Adopting a two component recombination/fragmentation model, validated by experimental information from STAR and PHENIX, we show that a cl

L. Borgonovo, C. -I. Bjornsson

The statistical properties of a complete, flux limited sample of 197 long gamma--ray bursts (GRBs) detected by BATSE are studied. In order to bring forth their main characteristics, care was taken to define a representative set of ten parameters. A multivariate analysis gives that ~70% of the total variation in parameter values is driven by only three princi

M. Molina, A. Malizia, L. Bassani, A. J. Bird

In this paper we present INTEGRAL observations of 7 AGNs: two newly discovered type 1 Seyferts, IGR J18027-1455 and IGR J21247+5058, and five well known Seyferts, NGC 6814 (type 1.5), Cyg A (Type 2), MCG-05-23-16 (type 2), ESO 103-G035 (type2) and GRS1734-292. For IGR J18027-1455 and IGR J21247+5058 only INTEGRAL/IBIS data were available, while broadband spe

Martin M. Block

The status of hadron-hadron interactions is reviewed, with emphasis on the forward and near-forward scattering regions. From analyticity, Finite Energy Sum Rules are introduced from which new analyticity constraints are derived that exploit the many very accurate low energy experimental cross sections, i.e., they constrain the values of the asymptotic cross

J. Bastos, J. Carvalho, M. Schmelling

A statistical method which uses a combination of two subdetectors to monitor the luminosity in high energy interactions is presented. To illustrate its performance, this method was applied to random triggered minimum bias data collected in the commissioning period of the HERA-B experiment in spring 2000. It is found that luminosity estimates with an intrinsi

E. Ripamonti, M. Mapelli, A. Ferrara

We derive the effects of DM decays and annihilations on structure formation. We consider moderately massive DM particles (sterile neutrinos and light DM), as they are expected to give the maximum contribution to heating and reionization. The energy injection from DM decays and annihilations produces both an enhancement in the abundance of coolants (H2 and HD

Sean Timothy Paul, Gang Tian

The Mabuchi K-energy map is exhibited as a singular metric on the refined CM polarization of any equivariant family $\mathbf{X}\overset{p}{\to} S$. Consequently we show that the generalized Futaki invariant is the leading term in the asymptotics of the reduced K-energy of the generic fiber of the map $p$. Properness of the K-energy implies that the generaliz

E. Ripamonti, M. Mapelli, A. Ferrara

We derive the evolution of the energy deposition in the intergalactic medium (IGM) by dark matter (DM) decays/annihilations for both sterile neutrinos and light dark matter (LDM) particles. At z > 200 sterile neutrinos transfer a fraction f_abs~0.5 of their rest mass energy into the IGM; at lower redshifts this fraction becomes <~ 0.3 depending on the partic

R. Valdarnini

Results from a large sample of hydrodynamical/N-body simulations of galaxy clusters in a LCDM cosmology are used to simulate cluster X-ray observations as expected from Chandra observations. The physical modeling of the gas includes radiative cooling, star formation, energy feedback and metal enrichment. The biasing of spectral temperatures with respect to m

C. Cawlfield, CLEO Collaboration

We have studied the Cabibbo-suppressed decay mode D^0 into K^+ K^- pi^0 using a Dalitz plot technique and find the strong phase difference delta_D [defined as delta_(K*^- K^+) - delta_(K*^+ K^-)] = 332 degrees +- 8 degrees +- 11 degrees and relative amplitude r_D [defined as a_(K*^- K^+) / a_(K*^+ K^-)] = 0.52 +- 0.05 +- 0.04. This measurement indicates sign

Fabio Gavarini

The radical of the Brauer algebra B_f^x is known to be non-trivial when the parameter x is an integer subject to certain conditions (with respect to f). In these cases, we display a wide family of elements in the radical, which are explicitly described by means of the diagrams of the usual basis of B_f^x . The proof is by direct approach for x=0, and via cla

Eyal Feigenbaum, Meir Orenstein

Optical plasmon-polariton modes confined in both transverse dimensions to significantly less than a wavelength are exhibited in open waveguides structured as sharp metal wedges. The analysis reveals two distinctive modes corresponding to a localized mode on the wedge point and surface mode propagation on the abruptly bent interface. These predictions are acc

Stephan Dahlke, Erich Novak, Winfried Sickel

We study the optimal approximation of the solution of an operator equation Au=f by linear and nonlinear mappings. We identify those cases where optimal nonlinear approximation is better than optimal linear approximation.

Stephan Dahlke, Erich Novak, Winfried Sickel

We study the optimal approximation of the solution of an operator equation Au=f by linear and nonlinear mappings.

Anton Alekseev, Damien Calaque

In this paper we quantize symplectic dynamical r-matrices over a possibly nonabelian base. The proof is based on the fact that the existence of a star-product with a nice property (called strong invariance) is sufficient for the existence of a quantization. We also classify such quantizations and prove a quantum analogue of the classical composition formula

Ryusuke Ikeda

The electric conductivities in glass phases of three-dimensional (3D) granular superconductors in magnetic fields are examined based on a quantum disordered Josephson-junction array. A correct inclusion of the Ohmic dissipative dynamics leads to glass phases with divergent dc conductivity. In contrast, with no dissipative term, a metallic response in a glass

J. Fleischer, J. Gluza, A. Lorca, T. Riemann

The luminosity measurement at the projected International Linear $e^+e^-$ Collider ILC is planned to be performed with forward Bhabha scattering with an accuracy of the order of $10^{-4}$. A theoretical prediction of the differential cross-section has to include one-loop weak corrections, with leading higher order terms, and the complete two-loop QED correct

Miloslav Znojil

Even if the motion of a quantum (quasi-)particle proceeds along a left-right-symmetric (PT-symmetric) curved path in complex plane, the spectrum of bound states may remain physical, i.e., real and bounded below). We propose a generalization. Firstly, we show how the topologically less trivial (tobogganic) contours may be allowed to live on several sheets of

Spyros D. Avramis, Konstadinos Sfetsos

Following a recent proposal, we employ the AdS/CFT correspondence to compute the jet quenching parameter for N=4 Yang-Mills theory at nonzero R-charge densities. Using as dual supergravity backgrounds non-extremal rotating branes, we find that the presence of the R-charges generically enhances the jet quenching phenomenon. However, at fixed temperature, this

Bernd Gärtner, Jirka Matousek, Leo Rüst, Petr Skovron

Sharir and Welzl introduced an abstract framework for optimization problems, called LP-type problems or also generalized linear programming problems, which proved useful in algorithm design. We define a new, and as we believe, simpler and more natural framework: violator spaces, which constitute a proper generalization of LP-type problems. We show that Clark

E. Rodney Canfield, Catherine Greenhill, Brendan D. McKay

Let S=(s_1,s_2,..., s_m) and T = (t_1,t_2,..., t_n) be vectors of non-negative integers with sum_{i=1}^{m} s_i = sum_{j=1}^n t_j. Let B(S,T) be the number of m*n matrices over {0,1} with j-th row sum equal to s_j for 1 <= j <= m and k-th column sum equal to t_k for 1 <= k <= n. Equivalently, B(S,T) is the number of bipartite graphs with m vertices in one par

Jounghun Lee, Daeseong Park

We present a theoretical study of void spins and their correlation properties. The concept of the spin angular momentum for an unbound void is introduced to quantify the effect of the tidal field on the distribution of matter that make up the void. Both the analytical and numerical approaches are used for our study. Analytically, we adopt the linear tidal to

Yasuaki Hikida

We compute correlation functions of closed strings in Misner space, a big crunch big bang universe. We develop a general method for correlators with twist fields, which are relevant for the investigation on the condensation of winding tachyon. We propose to compute the correlation functions by performing an analytic continuation of the results in C/Z_N Eucli

Jared Wunsch

Let $P_h$ be a self-adjoint semiclassical pseudodifferential operator on a manifold $M$ such that the bicharacteristic flow of the principal symbol on $T^*M$ is completely integrable and the subprincipal symbol of $P_h$ vanishes. Consider a semiclassical family of eigenfunctions, or, more generally, quasimodes $u_h$ of $P_h.$ We show that on a nondegenerate

Wojciech Gajda, Krzysztof Gornisiewicz

We consider a local to global principle for detecting linear dependence of nontorsion points, by reduction maps, in the Mordell-Weil group of an abelian variety over a number field.

Kirill Vankov

We obtain an explicit formula for the spherical image of the polynomial fraction conjectured by Shimura in 1963 for generating Hecke series in particular case of genus 4. As in our previous work we used the Satake spherical map for ${\rm Sp}_4$ and formulas by Andrianov. Key words: Hecke operators, Dirichlet series, Euler factorization, spherical map.

M. Bianchi, J. Kluson

We perform a Hamiltonian analysis of the classical type IIB superstring on AdS(5) x S(5) in the pure spinor approach. Taking the spatial components of the left-invariant (super)currents and the pure spinor ghosts as canonical variables, we compute the classical graded Poisson brackets of the currents and ghosts and identify the first class constraints associ

Wilfried Buchmuller, Koichi Hamaguchi, Oleg Lebedev, Michael Ratz

We desribe in detail a Z_6 orbifold compactification of the heterotic E_8 x E_8 string which leads to the (supersymmetric) standard model gauge group and matter content. The quarks and leptons appear as three 16-plets of SO(10), two of which are localized at fixed points with local SO(10) symmetry. The model has supersymmetric vacua without exotics at low en

Jens Koch, Felix von Oppen, A. V. Andreev

Strong coupling of electronic and vibrational degrees of freedom entails a low-bias suppression of the current through single-molecule devices, termed Franck-Condon blockade. In the limit of slow vibrational relaxation, transport in the Franck-Condon-blockade regime proceeds via avalanches of large numbers of electrons, which are interrupted by long waiting

Davide Pietrobon, Amedeo Balbi, Domenico Marinucci

We cross-correlate the new 3 year Wilkinson Microwave Anistropy Probe (WMAP) cosmic microwave background (CMB) data with the NRAO VLA Sky Survey (NVSS) radio galaxy data, and find further evidence of late integrated Sachs-Wolfe (ISW) effect taking place at late times in cosmic history. Our detection makes use of a novel statistical method \cite{Baldi et al.

Lars Kadison

An algebra extension A | B is right depth two if its tensor-square A\otimes_B A is in the Dress category Add A as A-B-bimodules. We consider necessary conditions for right, similarly left, D2 extensions in terms of partial A-invariance of two-sided ideals in A contracted to the centralizer. Finite dimensional algebras extending central simple algebras are sh

Istvan Gyöngy, Annie Millet

Stochastic evolution equations in Banach spaces with unbounded nonlinear drift and diffusion operators are considered. Under some regularity condition assumed for the solution, the rate of convergence of implicit Euler approximations is estimated under strong monotonicity and Lipschitz conditions. The results are applied to a class of quasilinear stochastic

Giuseppe Bimonte

This paper has been withdrawn, because relevant publications, related to the subject of the paper, were overlooked by the author.

Camille Ducoin, Philippe Chomaz, Francesca Gulminelli

This paper focuses on the isospin properties of the asymmetric nuclear-matter liquid-gas phase transition analyzed in a mean-field approach, using Skyrme effective interactions. We compare two different mechanisms of phase separation for low-density matter: equilibrium and spinodal decomposition. The isospin properties of the phases are deduced from the free

R. Mahnke, J. Kaupuzs, J. Hinkel, H. Weber

Application of thermodynamics to driven systems is discussed. As particular examples, simple traffic flow models are considered. On a microscopic level, traffic flow is described by Bando&#39;s optimal velocity model in terms of accelerating and decelerating forces. It allows to introduce kinetic, potential, as well as total energy, which is the internal ene

J. C. Taylor

I examine the arguments which have been given for quantum fluctuation-dissipation theorems. I distinguish between a weak form of the theorem, which is true under rather general conditions, and a strong form which requires a Langevin equation for its statement. I argue that the latter has not been reliably derived.

B. Trauzettel, Ya. M. Blanter, A. F. Morpurgo

Photon-assisted electron transport in ballistic graphene is analyzed using scattering theory. We show that the presence of an ac signal (applied to a gate electrode in a region of the system) has interesting consequences on electron transport in graphene, where the low energy dynamics is described by the Dirac equation. In particular, such a setup describes

Hongki Min, J. E. Hill, N. A. Sinitsyn, B. R. Sahu

Starting from a microscopic tight-binding model and using second order perturbation theory, we derive explicit expressions for the intrinsic and Rashba spin-orbit interaction induced gaps in the Dirac-like low-energy band structure of an isolated graphene sheet. The Rashba interaction parameter is first order in the atomic carbon spin-orbit coupling strength

Boris Ravaine, Andrei Derevianko, P. R. Berman

We investigate the feasibility of combining Raman optical lattices with a quantum computing architecture based on lattice-confined magnetically interacting neutral atoms. A particular advantage of the standing Raman field lattices comes from reduced interatomic separations leading to increased interatomic interactions and improved multi-qubit gate performanc

Dmitri V. Fursaev

Entanglement entropy for a spatial partition of a quantum system is studied in theories which admit a dual description in terms of the anti-de Sitter (AdS) gravity one dimension higher. A general proof of the holographic formula which relates the entropy to the area of a codimension 2 minimal hypersurface embedded in the bulk AdS space is given. The entangle

Supratik Pal

We show how braneworld cosmology with bulk matter can explain structure formation. In this scenario, the nonlocal corrections to the Friedmann equations supply a Weyl fluid that can dominate over matter at late times due to the energy exchange between the brane and the bulk. We demonstrate that the presence of the Weyl fluid radically changes the perturbatio

Xuezhao Bao

The migration of U and Th inside a planet is controlled by its oxidation state imposed by the volatile composition. In the deep interior of a planet, an absence of oxidative volatiles will cause U and Th to stay in a state of metal or low valance compounds with a big density. Consequently, they migrate to the bottom of its mantle first, and then are graduall

Ludwik Dabrowski, Francesco D&#39;Andrea, Giovanni Landi, Elmar Wagner

We construct spectral triples on all Podles quantum spheres. These noncommutative geometries are equivariant for a left action of $U_q(su(2))$ and are regular, even and of metric dimension 2. They are all isospectral to the undeformed round geometry of the 2-sphere. There is also an equivariant real structure for which both the commutant property and the fir

Christoph Dankert, Richard Cleve, Joseph Emerson, Etera Livine

We develop the concept of a unitary t-design as a means of expressing operationally useful subsets of the stochastic properties of the uniform (Haar) measure on the unitary group U(2^n) on n qubits. In particular, sets of unitaries forming 2-designs have wide applicability to quantum information protocols. We devise an O(n)-size in-place circuit construction

Noam Soker, Romuald Tylenda

We derive the constraints on the mass ratio for a binary system to merge in a violent process. We find that the secondary to primary stellar mass ratio should be ~0.003 < (M_2/M_1) < ~0.15. A more massive secondary star will keep the primary stellar envelope in synchronized rotation with the orbital motion until merger occurs. This implies a very small relat

Yasumi Abe

We present a new procedure for quantizing field theory models on a noncommutative spacetime. The new quantization depends on the noncommutative parameter explicitly and reduces to the canonical quantization in the commutative limit. It is shown that a quantum field theory constructed by the new quantization yeilds exactly the same correlation functions as th

Hua-Xing Chen, Atsushi Hosaka, Shi-Lin Zhu

We use the method of QCD sum rules to investigate the isospin symmetry breaking of K and K* mesons. The electromagnetic effect, difference between up and down current-quark masses and difference between up and down quark condensates are important. We perform sum rule analyses of their masses and decay constant differences, which are consistent with experimen

Rafael H. Villarreal

In this note we give a combinatorial characterization of all the unmixed bipartite graphs.

Kevin Cahill

The hybrid form is a combination of the Rydberg potential and the London inverse-sixth-power energy. It is accurate at all relevant distance scales and simple enough for use in all-atom simulations of biomolecules. One may compute the parameters of the hybrid potential for the ground state of a pair of neutral atoms from their internuclear separation, the de

Juergen Herzog, Takayuki Hibi, Satoshi Murai, Ngo Viet Trung

A forest is the clique complex of a strongly chordal graph and a quasi-forest is the clique complex of a chordal graph. Kruskal--Katona type theorems for forests, quasi-forests, pure forests and pure quasi-forests will be presented. In addition, it will be shown that a quasi-forest is shellable if and only if its $h$-vector $(h_0, h_1, h_2, ...)$ satisfies $

Jiawang Nie, James Demmel

This paper discusses how to find the global minimum of functions that are summations of small polynomials (``small&#39;&#39; means involving a small number of variables). Some sparse sum of squares (SOS) techniques are proposed. We compare their computational complexity and lower bounds with prior SOS relaxations. Under certain conditions, we also discuss ho

Stella Huerfano, Sarira Sahu, M. Socolovsky

We use the Feynman path integral approach to nonrelativistic quantum mechanics twofold. First, we derive the lagrangian for a spinless particle moving in a uniformly but not necessarily constantly accelerated reference frame; then, applying the strong equivalence principle (SEP) we obtain the Schroedinger equation for a particle in an inertial frame and in t

Pawel Kurzynski

Quantum walks are not only algorithmic tools for quantum computation but also not trivial models which describe various physical processes. The paper compares one-dimensional version of the free particle Dirac equation with discrete time quantum walk (DTQW). We show that the discretized Dirac equation when compared with DTQW results in interesting relations.

Daryl Achilles, Christine Silberhorn, Ian A. Walmsley

We experimentally investigate a method of directly characterizing the photon number distribution of nonclassical light beams that is tolerant to losses and makes use only of standard binary detectors. This is achieved in a single measurement by calibrating the detector using some small amount of prior information about the source. We demonstrate the techniqu

Xiao Zheng, Fan Wang, GuanHua Chen

We prove that the electron density function of a real physical system can be uniquely determined by its values on any finite subsystem. This establishes the existence of a rigorous density-functional theory for any open electronic system. By introducing a new density functional for dissipative interactions between the reduced system and its environment, we s

Somshubhro Bandyopadhyay, Gilad Gour, Barry C. Sanders

We establish duality for monogamy of entanglement: whereas monogamy of entanglement inequalities provide an upper bound for bipartite sharability of entanglement in a multipartite system, we prove that the same quantity provides a \emph{lower} bound for distribution of bipartite entanglement in a multipartite system. Our theorem for monogamy of entanglement

S. Garnerone, A. Marzuoli, M. Rasetti

We construct a quantum algorithm to approximate efficiently the colored Jones polynomial of the plat presentation of any oriented link L at a fixed root of unity q. Our construction is based on SU(2) Chern-Simons topological quantum field theory (and associated Wess-Zumino-Witten conformal field theory) and exploits the q-deformed spin network as computation

E. Bagan, J. Calsamiglia, R. Demkowicz-Dobrzanski, R. Munoz-Tapia

We present a procedure to share a secret spatial direction in the absence of a common reference frame using a multipartite quantum state. The procedure guarantees that the parties can determine the direction if they perform joint measurements on the state, but fail to do so if they restrict themselves to local operations and classical communication (LOCC). W

F. Palumbo, A. Napoli, A. Messina

The quantum dynamics of M pairwise coupled spin 1/2 is analyzed and the time evolution of the entanglement get established within a prefixed couple of spins is studied. A conceptual and quantitative link between the concurrence function and measurable quantities is brought to light providing a physical interpretation for the concurrence itself as well as a w

Feng Shuang, Herschel Rabitz

This paper explores the use of laboratory closed-loop learning control to either fight or cooperate with decoherence in the optimal manipulation of quantum dynamics. Simulations of the processes are performed in a Lindblad formulation on multilevel quantum systems strongly interacting with the environment without spontaneous emission. When seeking a high con

Sara Cuenda, Angel Sanchez, Niurka R. Quintero

In this work we analyze the possibility that soliton dynamics in a simple nonlinear model allows functionally relevant predictions of the behaviour of DNA. This suggestion was first put forward by Salerno [Phys. Rev. A, vol. 44, p. 5292 (1991)] by showing results indicating that sine-Gordon kinks were set in motion at certain regions of a DNA sequence that i

Jan Karbowski, Christopher J. Cronin, Adeline Seah, Jane E. Mendel

Undulatory locomotion is common to nematodes as well as to limbless vertebrates, but its control is not understood in spite of the identification of hundred of genes involved in Caenorhabditis elegans locomotion. To reveal the mechanisms of nematode undulatory locomotion, we quantitatively analyzed the movement of C. elegans with genetic perturbations to neu

Thor Gjesdal, Carl Erik Wasberg, Bjorn Anders Pettersson Reif, Oyvind Andreassen

One of the more promising recent approaches to turbulence modelling is the Variational Multiscale Large Eddy Simulation (VMS LES) method proposed by Hughes et al. [Comp. Visual. Sci., vol. 3, pp. 47-59, 2000]. This method avoids several conceptual issues of traditional filter-based LES by employing a priori scale partitioning in the discretization of the Nav

O. Germain, G. Ruffini

We address the feasibility of a GNSS-R code-altimetry space mission and more specifically a dominant term of its error budget: the reflected-signal range precision. This is the RMS error on the reflected-signal delay, as estimated by waveform retracking. So far, the approach proposed by [Lowe et al., 2002] has been the state of the art to theoretically evalu

Harrison B. Prosper

These lectures introduce key concepts in probability and statistical inference at a level suitable for graduate students in particle physics. Our goal is to paint as vivid a picture as possible of the concepts covered.

Tomislav Ivezic

An apparent paradox is obtained in all previous treatments of the Trouton-Noble experiment; there is a three-dimensional torque in an inertial frame S in which a thin parallel-plate capacitor is moving, but there is no 3D torque in S&#39;, the rest frame of the capacitor. In this paper instead of using 3D quantities and their ``apparent&#39;&#39; transformat

Zhongyuan Zhou, Shih-I Chu

We present a spin-dependent localized Hartree-Fock (SLHF) density-functional approach for the treatment of the inner-shell excited-state calculation of atomic systems. In this approach, the electron spin-orbitals in an electronic configuration are obtained first by solving Kohn-Sham (KS) equation with SLHF exchange potential. Then a single-Slater-determinant

V. A. Panchelyuga, S. E. Shnoll

The present investigation is dedicated to study of physical basis of macroscopic fluctuations effect. In particular experimental investigation of possible influence of rapidly spinning massive body on distribution function of the alpha-decay rate fluctuations was carried out. Possible anisotropy of such influence was tested. The paper also contains fundament

Robert J. Buenker

It is pointed out that the traditional explanation for the observation of a non-zero energy h nu for light in free space does not apply for the analogous situation in dispersive media. Because the speed of light u is no longer equal to c in this case, the key quantity, gamma = (1-u2/c2)-0.5, is finite as a result. Since the rest energy of photons is believed

J. -M. Levy

An elementary thought experiment is used to show that once the time dilatation effect is established, there is no way to escape a dual length contraction.

Benjamin Dollet, Francois Graner

We investigate the two-dimensional flow of a liquid foam around circular obstacles by measuring all the local fields necessary to describe this flow: velocity, pressure, bubble deformations and rearrangements. We show how our experimental setup, a quasi-2D &#34;liquid pool&#34; system, is adapted to the determination of these fields: the velocity and bubble

Feng Shuang, Herschel Rabitz

This paper investigates the impact of control field noise on the optimal manipulation of quantum dynamics. Simulations are performed on several multilevel quantum systems with the goal of population transfer in the presence of significant control noise. The noise enters as run-to-run variations in the control amplitude and phase with the observation being an

Q. H. Zhang, L. Huo, W. N. Zhang

We have used a simple spectrum distribution which was derived from a hydrodynamical equation\cite{Csorgo} to fit the data of the STAR group. It is found that it can fit the $v_2$ of STAR group very well. We have found that $v_2$ is sensitive to both the effective temperature of particles and the expanding velocity. We have suggested a new variable ${\bf z}$

T. Duguet, K. Bennaceur, T. Lesinski, J. Meyer

We discuss some of the challenges that the DFT community faces in its quest for the truly universal energy density functional applicable over the entire nuclear chart.