April 2008 arXiv papers — page 44

Oliver Schuetze, Carlos A. Coello Coello, Emilia Tantar, El-Ghazali Talbi

Recently, a framework for the approximation of the entire set of $ε$-efficient solutions (denote by $E_ε$) of a multi-objective optimization problem with stochastic search algorithms has been proposed. It was proven that such an algorithm produces -- under mild assumptions on the process to generate new candidate solutions --a sequence of archives which conv

F. Furtado, F. Pereira, S. Ribeiro

We compare the Kurganov-Tadmor (KT) two-dimensional second order semi-discrete central scheme in dimension by dimension formulation with a new two-dimensional approach introduced here and applied in numerical simulations for two-phase, two-dimensional flows in heterogeneous formations. This semi-discrete central scheme is based on the ideas of Rusanov's

Arkadius Kalka, Mina Teicher, Boaz Tsaban

On March 2004, Anshel, Anshel, Goldfeld, and Lemieux introduced the \emph{Algebraic Eraser} scheme for key agreement over an insecure channel, using a novel hybrid of infinite and finite noncommutative groups. They also introduced the \emph{Colored Burau Key Agreement Protocol (CBKAP)}, a concrete realization of this scheme. We present general, efficient heu

T. Iwashita, Y. Nakayama, R. Yamamoto

We present a numerical method that consistently implements thermal fluctuations and hydrodynamic interactions to the motion of Brownian particles dispersed in incompressible host fluids. In this method, the thermal fluctuations are introduced as random forces acting on the Brownian particles. The hydrodynamic interactions are introduced by directly resolving

Mark Hannam, Sascha Husa, Frank Ohme, Bernd Bruegmann

We expand upon our previous analysis of numerical moving-puncture simulations of the Schwarzschild spacetime. We present a derivation of the family of analytic stationary 1+log foliations of the Schwarzschild solution, and outline a transformation to isotropic-like coordinates. We discuss in detail the numerical evolution of standard Schwarzschild puncture d

Paul Fendley

I define models of quantum loops and nets which have ground states with topological order. These make possible excited states comprised of deconfined anyons with non-abelian braiding. With the appropriate inner product, these quantum loop models are equivalent to net models whose topological weight involves the chromatic polynomial. A useful consequence is t

Qiang Wu, N. O. Santos, Pamela Vo, Anzhong Wang

Recently, in Gong {\em et al} \cite{GWW07} and Wang and Santos \cite{WS07} it was shown that the effective cosmological constant on each of the two orbifold branes can be easily lowered to its current observational value, by using the large extra dimensions in the framework of both M-Theory and string theory on $S^{1}/Z_{2}$. In this paper, we study the curr

Christian G. Boehmer

Inflation driven by a single dark spinor field is discussed. We define the notion of a dark spinor field and derive the cosmological field equations for such a matter source. The conditions for inflation are determined and an exactly solvable model is presented. We find the power spectrum of the quantum fluctuation of this field and compare the results with

Stijn Wuyts, Ivo Labbe, Natascha M. Forster Schreiber, Marijn Franx

We present a Ks-selected catalog, dubbed FIREWORKS, for the Chandra Deep Field South (CDFS) containing photometry in U_38, B_435, B, V, V_606, R, i_775, I, z_850, J, H, Ks, [3.6 um], [4.5 um], [5.8 um], [8.0 um], and the MIPS [24 um] band. The imaging has a typical Ks limit of 24.3 mag (5 sigma, AB) and coverage over 113 arcmin^2 in all bands and 138 arcmin^

Rodolfo Casana, Manoel M. Ferreira, Carlos E. H. Santos

In the present work, we investigate classical solutions of the Maxwell-Carroll-Field-Jackiw-Proca (MCFJP) electrodynamics for the cases a purely timelike and spacelike Lorentz-violating (LV) background. Starting from the MCFJP Lagrangian and the associated wave equations written for the potential four-vector, the tensor form of the Green function is achieved

Sebastian Guttenberg, George Savvidy

This review is devoted to the Schwinger and Fronsdal theory of Abelian tensor gauge fields. The theory describes the propagation of free massless gauge bosons of integer helicities and their interaction with external currents. Self-consistency of its equations requires only the traceless part of the current divergence to vanish. The essence of the theory is

Fulvio Baldovin, Pierre-Henri Chavanis, Enzo Orlandini

On the basis of analytical results and molecular dynamics simulations we clarify the nonequilibrium dynamics of a long-range interacting system in contact with a heat bath. For small couplings with the bath, we show that the system can first be trapped in a Vlasov quasi-stationary state, then a microcanonical one follows, and finally canonical equilibrium is

Lisa L. Everett, Ian-Woo Kim, Peter Ouyang, Kathryn M. Zurek

We present a general phenomenological framework for dialing between gravity mediation, gauge mediation, and anomaly mediation. The approach is motivated from recent developments in moduli stabilization, which suggest that gravity mediated terms can be effectively loop suppressed and thus comparable to gauge and anomaly mediated terms. The gauginos exhibit a

Gabriele Mondello

We compare some natural triangulations of the Teichmüller space of hyperbolic surfaces with geodesic boundary and of some bordifications. We adapt Scannell-Wolf's proof to show that grafting semi-infinite cylinders at the ends of hyperbolic surfaces with fixed boundary lengths is a homeomorphism. This way, we construct a family of triangulations of the T

Guillaume Chapuy

A unicellular map is a map which has only one face. We give a bijection between a dominant subset of rooted unicellular maps of fixed genus and a set of rooted plane trees with distinguished vertices. The bijection applies as well to the case of labelled unicellular maps, which are related to all rooted maps by Marcus and Schaeffer's bijection. This give

Alioscia Hamma, Daniel A. Lidar

This paper has been withdrawn as it has been superseded by 0808.2697

Konstanze Jaehne, Klemens Hammerer, Margareta Wallquist

In this paper we present a scheme for ground state cooling of a flexural mode of a nanomechanical beam incorporated in a loop-shaped Cooper-pair box (CPB) circuit. Via the Lorentz force coupling of the beam motion to circulating CPB-circuit currents, energy is transferred to the CPB qubit which acts as a dissipative two-level system. The cooling process is d

P. N. Dowling, B. Randrianantoanina, B. Turett

A Banach space has the weak fixed point property if its dual space has a weak$^*$ sequentially compact unit ball and the dual space satisfies the weak$^*$ uniform Kadec-Klee property; and it has the \fpp if there exists $ε>0$ such that, for every infinite subset $A$ of the unit sphere of the dual space, $A\cup (-A)$ fails to be $(2-ε)$-separated. In particul

Stephen Kudla, Michael Rapoport

The supersingular locus in the fiber at p of a Shimura variety attached to a unitary similitude group GU(1,n-1) over Q is uniformized by a formal scheme \Cal N. In the case when p is inert, we define special cycles Z(x) in \Cal N, associated to a collection x of m `special homomorphisms' with fundamental matrix T in Herm_m(OK). When m=n and T is nonsingu

Stanley J. Brodsky, Guy F. de Teramond

Light-front holography is a remarkable feature of the AdS/CFT correspondence between gravity in AdS space and conformal field theories in physical space-time; it allows string modes $Φ(z)$ in the anti-de Sitter (AdS) fifth dimension to be precisely mapped to the light-front wavefunctions of hadrons in physical space-time in terms of a specific light-front im

Kostas Skenderis, Marika Taylor

The fuzzball proposal states that associated with a black hole of entropy S there are exp S horizon-free non-singular solutions that asymptotically look like the black hole but generically differ from the black hole up to the horizon scale. These solutions, the fuzzballs, are considered to be the black hole microstates while the original black hole represent

Davide Cassani

Type II supergravity on backgrounds admitting SU(3) x SU(3) structure and general fluxes is considered. Using the generalized geometry formalism, we study dimensional reductions leading to N=2 gauged supergravity in four dimensions, possibly with tensor multiplets. In particular, a geometric formula for the full N=2 scalar potential is given. Then we impleme

Luca Baiotti, Bruno Giacomazzo, Luciano Rezzolla

Binary neutron-star (BNS) systems represent primary sources for the gravitational-wave (GW) detectors. We present a systematic investigation in full GR of the dynamics and GW emission from BNS which inspiral and merge, producing a black hole (BH) surrounded by a torus. Our results represent the state of the art from several points of view: (i) We use HRSC me

Fabrizio Dolcini, Luca Dell'Anna

We study the out-of-equilibrium current through a multilevel quantum dot contacted to two superconducting leads and in the presence of Rashba and Dresselhaus spin-orbit couplings, in the regime of strong dot-lead coupling. The multiple Andreev reflection (MAR) subgap peaks in the current voltage characteristics are found to be modified (but not suppressed) b

M. M. Islam, J. Kaspar, R. J. Luddy

Deep-elastic pp scattering at c.m. energy 14 TeV at LHC in the momentum transfer range 4 GeV*2 < |t| < 10 GeV*2 is planned to be measured by the TOTEM group. We study this process in a model where the deep-elastic scattering is due to a single hard collision of a valence quark from one proton with a valence quark from the other proton. The hard collision ori

Marco Zoli

The decay rate for a particle in a metastable cubic potential is investigated in the quantum regime by the Euclidean path integral method in semiclassical approximation. The imaginary time formalism allows one to monitor the system as a function of temperature. The family of classical paths, saddle points for the action, is derived in terms of Jacobian ellip

Renzo Cavalieri, Paul Johnson, Hannah Markwig

Hurwitz numbers count genus g, degree d covers of the projective line with fixed branch locus. This equals the degree of a natural branch map defined on the Hurwitz space. In tropical geometry, algebraic curves are replaced by certain piece-wise linear objects called tropical curves. This paper develops a tropical counterpart of the branch map and shows that

Yulian V. Vanne, Alejandro Saenz

A theoretical comparison of the electronic excitation and ionisation behaviour of molecular hydrogen oriented either parallel or perpendicular to a linear polarised laser pulse is performed. The investigation is based on a non-perturbative treatment that solves the full time-dependent Schrödinger equation of both correlated electrons within the fixed-nuclei

Arseni Goussev, Daniel Waltner, Klaus Richter, Rodolfo A. Jalabert

We address the sensitivity of quantum mechanical time evolution by considering the time decay of the Loschmidt echo (LE) (or fidelity) for local perturbations of the Hamiltonian. Within a semiclassical approach we derive analytical expressions for the LE decay for chaotic systems for the whole range from weak to strong local perturbations and identify differ

Jorge Quintanilla, Klaus Capelle, Luiz N. Oliveira

A density-functional formalism for superconductivity {\em and} magnetism is presented. The resulting relations unify previously derived Kohn-Sham equations for superconductors and for non-collinear magnetism. The formalism, which discriminates Cooper pair singlets from triplets, is applied to two quantum liquids coupled by tunneling through a barrier. An exa

Sergio L. Cacciatori, Francesco Dalla Piazza, Bert van Geemen

A main issue in superstring theory are the superstring measures. D&#39;Hoker and Phong showed that for genus two these reduce to measures on the moduli space of curves which are determined by modular forms of weight eight and the bosonic measure. They also suggested a generalisation to higher genus. We showed that their approach works, with a minor modificat

B. Kerbikov, O. Lychkovskiy

We calculate the rate of neutron-mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

Jean-Francois Babadjian, Vincent Millot

This paper extends the result of \cite{BM} on the homogenization of integral functionals with linear growth defined for Sobolev maps taking values in a given manifold. Through a $Γ$-convergence analysis, we identify the homogenized energy in the space of functions of bounded variation. It turns out to be finite for $BV$-maps with values in the manifold. The

B. Enriquez, G. Halbout

We construct quantization functors of quasi-Lie bialgebras. We establish a bijection between this set of quantization functors, modulo equivalence and twist equivalence, and the set of quantization functors of Lie bialgebras, modulo equivalence. This is based on the acyclicity of the kernel of the natural morphism from the universal deformation complex of qu

Zacharia Myers, Adi Nusser

Weakly interacting massive particles (WIMPs) are a viable candidate for the relic abundance of dark matter (DM) produced in the early universe. So far WIMPs have eluded direct detection through interactions with baryonic matter. Neutrino emission from accumulated WIMP annihilations in the solar core has been proposed as a signature of DM, but has not yet bee

Andreas Holzner, Andreas Weichselbaum, Jan von Delft

We exploit the common mathematical structure of the numerical renormalization group and the density matrix renormalization group, namely, matrix product states, to implement an efficient numerical treatment of a two-lead, multi-level Anderson impurity model. By adopting a star-like geometry, where each species (spin and lead) of conduction electrons is descr

Heino Falcke

The radio technique for the detection of cosmic particles has seen a major revival in recent years. New and planned experiments in the lab and the field, such as GLUE, Anita, LUNASKA, Codalema, LOPES as well as sophisticated Monte Carlo experiments have produced a wealth of new information and I review here briefly some of the main results with the main focu

V. Trivedi

In char $k = p >0$, A. Langer proved a strong restriction theorem (in the style of H. Flenner) for semistable sheaves to a very general hypersurface of degree $d$, on certain varieties, with the condition that `char $k > d$&#39;. He remarked that to remove this condition, it is enough to answer either of the following questions affirmatively: {\it For the sy

Yulia Horishna, Igor Parasyuk, Lyudmyla Protsak

We consider a problem of finding vanishing at infinity $C^1([0,\oo))$-solutions to non-homogeneous system of linear ODEs which has the pole of first order at $x=0$. The resonant case where the corresponding homogeneous problem has nontrivial solutions is of main interest. Under the conditions that the homogeneous system is exponentially dichotomic on $[1,\oo

A. Paolino, M. Pizzi

Recently, Alekseev and Belinski have presented a new exact solution of the Einstein-Maxwell equations which describes two Reissner-Nordstrom (RN) sources in reciprocal equilibrium (no struts nor strings); one source is a naked singularity, the other is a black hole: this is the only possible configuration for separable object, apart from the well-known extre

J. M. Morbec, K. Capelle

We derive a closed analytical expression for the exchange energy of the three-dimensional interacting electron gas in strong magnetic fields, which goes beyond the quantum limit (L=0) by explicitly including the effect of the second, L=1, Landau level and arbitrary spin polarization. The inclusion of the L=1 level brings the fields to which the formula appli

Anselm Knebusch

In this paper we generalize the approximation theorem for L^2-Betti numbers to an approximation theorem for center-valued Betti-numbers.

Naresh Sharma

Quantum Fano inequality (QFI) in quantum information theory provides an upper bound to the entropy exchange by a function of the entanglement fidelity. We give various Fano-like upper bounds to the entropy exchange and QFI is a special case of these bounds. These bounds also give an alternate derivation of the QFI.

Kaiki Taro Inoue, Paolo Cabella, Eiichiro Komatsu

We develop a new interpolation scheme, based on harmonic inpainting, for reconstructing the cosmic microwave background temperature data within the Galaxy mask from the data outside the mask. We find that, for scale-invariant isotropic random Gaussian fluctuations, the developed algorithm reduces the errors in the reconstructed map for the odd-parity modes s

Samuel Grushevsky

In this paper we prove the $Γ_{00}$ conjecture of van Geemen and van der Geer, under the additional assumption that the matrix of coefficients of the tangent has rank at most 2. This assumption is satisfied by Jacobians, and thus our result gives a characterization of the locus of Jacobians among all principally polarized abelian varieties. The proof is by r

Hajime Aoki, Yoshiko Hirayama, Satoshi Iso

We consider a gauge-Higgs system on a fuzzy 2-sphere and study the topological structure of gauge configurations, when the U(2) gauge symmetry is spontaneously broken to U(1) times U(1) by the vev of the Higgs field. The topology is classified by the index of the Dirac operator satisfying the Ginsparg-Wilson relation, which turns out to be a noncommutative a

Vittorio Giovannetti, Simone Montangero, Rosario Fazio

Tensor networks representations of many-body quantum systems can be described in terms of quantum channels. We focus on channels associated with the Multi-scale Entanglement Renormalization Ansatz (MERA) tensor network that has been recently introduced to efficiently describe critical systems. Our approach allows us to compute the MERA correspondent to the t

Vasilis Chousionis

The aim of the present paper is twofold. We study directed porosity in connection with conformal iterated function systems (CIFS) and with singular integrals. We prove that limit sets of finite CIFS are porous in a stronger sense than already known. Furthermore we use directed porosity to establish that truncated singular integral operators, with respect to

Vasilis Chousionis

We construct a class of singular integral operators associated with homogeneous Calderón-Zygmund standard kernels on $d$-dimensional, $d <1$, Sierpinski gaskets $E_d$. These operators are bounded in $L^2(μ_d)$ and their principal values diverge $μ_d$ almost everywhere, where $μ_d$ is the natural (d-dimensional) measure on $E_d$.

Riccardo Salvati Manni

Very recently, Grushevsky continued D&#39;Hoker and Phong&#39;s program of finding the chiral superstring measure from first principles by constructing modular forms satisfying certain factorization constraints. He has proposed an ansatz in genus 4 and conjectured a possible formula for the superstring measure in any genus, subject to the condition that cert

F. Caruso, J. Eisert, V. Giovannetti, A. S. Holevo

A complete analysis of multi-mode bosonic Gaussian channels is proposed. We clarify the structure of unitary dilations of general Gaussian channels involving any number of bosonic modes and present a normal form. The maximum number of auxiliary modes that is needed is identified, including all rank deficient cases, and the specific role of additive classical

Daniil Ryabko, Boris Ryabko

In this work a method for statistical analysis of time series is proposed, which is used to obtain solutions to some classical problems of mathematical statistics under the only assumption that the process generating the data is stationary ergodic. Namely, three problems are considered: goodness-of-fit (or identity) testing, process classification, and the c

Gaelle Keller, Virginia D&#39;Auria, Nicolas Treps, Thomas Coudreau

We report the first experimental observation of bright EPR beams produced by a type-II optical parametric oscillator operating above threshold at frequency degeneracy. The degenerate operation is obtained by introducing a birefringent plate inside the cavity resulting in phase locking. After filtering the pump noise, which plays a critical role, continuous-v

Josef Lindman Hörnlund, Fredrik Ohlsson

The moduli space of flat connections for maximally supersymmetric Yang-Mills theories, in a space-time of the form T^3xR, contains isolated points, corresponding to normalizable zero energy states, for certain simple gauge groups G. We consider the low energy effective field theories in the weak coupling limit supported on such isolated points and find that

Yuchun Guo, Changjia Chen, Shi Zhou

A network&#39;s topology information can be given as an adjacency matrix. The bitmap of sorted adjacency matrix(BOSAM) is a network visualisation tool which can emphasise different network structures by just looking at reordered adjacent matrixes. A BOSAM picture resembles the shape of a flower and is characterised by a series of &#39;leaves&#39;. Here we sh

L. Girardi, J. Dalcanton, B. Williams, R. de Jong

We present extensive tables of bolometric corrections and interstellar extinction coefficients for the WFPC2 and ACS (both WFC and HRC) photometric systems. They are derived from synthetic photometry applied to a database of spectral energy distributions covering a large range of effective temperatures, surface gravity, and metal content. Carbon stars are al

Ippei Danshita, Carlos A. R. Sá de Melo

We perform a stability analysis of superfluid (SF) and supersolid (SS) phases of polarized dipolar bosons in two-dimensional optical lattices at high filling factors and zero temperature, and obtain the phase boundaries between SF, checkerboard SS (CSS), striped SS (SSS), and collapse. We show that the phase diagram can be explored through the application of

Miquel Trias, Alicia M. Sintes

We study parameter estimation of supermassive black holes in the range $10^5-10^8\Ms$ by LISA using the inspiral full post-Newtonian gravitational waveforms, and we compare the results with those arising from the commonly used restricted post-Newtonian approximation. The analysis shows that for observations of the last year before merger, the inclusion of th

Jesús Zavala, Pablo F. Velázquez, Adriano H. Cerqueira, Gloria M. Dubner

We present 3D hydrodynamical simulations of a precessing jet propagating inside a supernova remnant (SNR) shell, particularly applied to the W50-SS433 system in a search for the origin of its peculiar elongated morphology. Several runs were carried out with different values for the mass loss rate of the jet, the initial radius of the SNR, and the opening ang

Matthias R. Gaberdiel, Christoph A. Keller

We show that every modular differential equation of a rational conformal field theory comes from a null vector in the vacuum Verma module. We also comment on the implications of this result for the consistency of the extremal self-dual conformal field theories at c=24 k.

Yue Yu, Tieyan Si

The exact solubility of the Kitaev-type spin honeycomb lattice model was proved by means of a Majorana fermion representation or a Jordan-Wigner transformation while the explicit form of the anyon in terms of Pauli matrices became not transparent. The nonabelian statistics of anyons and the fusion rules can only be expressed in indirect ways to Pauli matrice

Antonis Papapantoleon

These lectures notes aim at introducing Lévy processes in an informal and intuitive way, accessible to non-specialists in the field. In the first part, we focus on the theory of Lévy processes. We analyze a `toy&#39; example of a Lévy process, viz. a Lévy jump-diffusion, which yet offers significant insight into the distributional and path structure of a Lév

A. Lubotzky, E. Zelmanov

We show that there exists $k \in \bbn$ and $0 < \e \in\bbr$ such that for every field $F$ of characteristic zero and for every $n \in \bbn$, there exists explicitly given linear transformations $T_1,..., T_k: F^n \to F^n$ satisfying the following: For every subspace $W$ of $F^n$ of dimension less or equal $\frac n2$, $ \dim(W+\suml^k_{i=1} T_iW) \ge (1+\e) \

Nicolas Jacon, Cédric Lecouvey

This note is concerned with a natural generalization of the Mullineux involution for Ariki-Koike algebras. Using a result of Fayers together with previous results by the authors, we give an efficient algorithm for computing this generalized Mullineux involution. Our algorithm notably does not involve the determination of paths in affine crystals.

Takahiro Hatano

We investigate the rheological properties of an assembly of inelastic (but frictionless) particles close to the jamming density using numerical simulation, in which uniform steady states with a constant shear rate $\dotγ$ is realized. The system behaves as a power-law fluid and the relevant exponents are estimated; e.g., the shear stress is proportional to $

F. Alonso-Marroquin, Yucang Wang

The most difficult aspect of the realistic modeling of granular materials is how to capture the real shape of the particles. Here we present a method to simulate granular materials with complex-shaped particles. The particle shape is represented by the classical concept of a Minkowski sum, which permits the representation of complex shapes without the need t

C. Allton, D. J. Antonio, Y. Aoki, T. Blum

We have simulated QCD using 2+1 flavors of domain wall quarks on a $(2.74 {\rm fm})^3$ volume with an inverse lattice scale of $a^{-1} = 1.729(28)$ GeV. The up and down (light) quarks are degenerate in our calculations and we have used four values for the ratio of light quark masses to the strange (heavy) quark mass in our simulations: 0.217, 0.350, 0.617 an

Yu Kawakami

We give the best possible upper bound on the number of exceptional values and the totally ramified value number of the hyperbolic Gauss map for pseudo-algebraic constant mean curvature one surfaces in the hyperbolic three-space and some partial results on the Osserman problem for algebraic case. Moreover, we study the value distribution of the hyperbolic Gau

Masahiro Takeoka, Hiroki Takahashi, Masahide Sasaki

Theoretical analysis is given for a two-photon subtraction from a continuous wave (CW) squeezed vacuum with finite time separation between two detection events. In the CW photon subtraction process, the generated states are inevitably described by temporal mutimode states. Our approach is based on Schrödinger picture which provides mathematically simple form

Weihua Li, Junhao Shen

Let $\mathcal A$ be a separable, unital, approximately divisible C$^*$-algebra. We show that $\mathcal A$ is generated by two self-adjoint elements and the topological free entropy dimension of any finite generating set of $\mathcal A$ is less than or equal to 1. In addition, we show that the similarity degree of $\mathcal A$ is at most 5. Thus an approximat

Mankei Tsang, Jeffrey H. Shapiro, Seth Lloyd

We propose a general quantum theory of optical phase and instantaneous frequency in the time domain for slowly varying optical signals. Guided by classical estimation theory, we design homodyne phase-locked loops that enable quantum-limited measurements of temporal phase and instantaneous frequency. Standard and Heisenberg quantum limits to such measurements

B. M. Gaensler, A. Tanna, P. O. Slane, C. L. Brogan

We present an XMM-Newton observation of the long-overlooked radio source G350.1-0.3. The X-ray spectrum of G350.1-0.3 can be fit by a shocked plasma with two components: a high-temperature (1.5 keV) region with a low ionization time scale and enhanced abundances, plus a cooler (0.36 keV) component in ionization equilibrium and with solar abundances. The X-ra

Dan Solomon

Point splitting has been suggested as a way to deal with anomalous commutators in quantum field theory. It has been pointed out by D.G. Boulware[4] that in order to obtain a mathematically consistent theory the Hamiltonian operator must be point split also. We will examine the effect of point splitting the Hamiltonian for a free fermion field in 1-1D space-t

Emanuel Milman

This is a continuation of our previous work 0712.4092. It is well known that various isoperimetric inequalities imply their functional ``counterparts&#39;&#39;, but in general this is not an equivalence. We show that under certain convexity assumptions (e.g. for log-concave probability measures in Euclidean space), the latter implication can in fact be rever

Damon M. Hay, J. William Helton, Adrian Lim, Scott McCullough

Let $p$ be a polynomial in the non-commuting variables $(a,x)=(a_1,...,a_{g_a},x_1,...,x_{g_x})$. If $p$ is convex in the variables $x$, then $p$ has degree two in $x$ and moreover, $p$ has the form $p = L + Λ^T Λ,$ where $L$ has degree at most one in $x$ and $Λ$ is a (column) vector which is linear in $x,$ so that $Λ^TΛ$ is a both sum of squares and homogen

Wen-Xiu Ma

A general Casoratian formulation is proposed for the 2D Toda lattice equation, which involves coupled eigenfunction systems. Various Casoratian type solutions are generated, through solving the resulting linear conditions and using a Baecklund transformation.

Yanpeng Yao, Huaxiang Fu

Using density-functional calculations we study the structure and polarization response of tetragonal PbTiO3, BaTiO3 and SrTiO3 in a strain regime that is previously overlooked. Different from common expectations, we find that the polarizations in all three substances saturate at large strains, demonstrating a universal phenomenon. The saturation is shown to

Ferihe Atalan, Mustafa Korkmaz

We compute the growth series and the growth functions of reducible and pseudo-Anosov elements of the pure mapping class group of the sphere with four holes with respect to a certain generating set. We prove that the ratio of the number of pseudo-Anosov elements to that of all elements in a ball with center at the identity tends to one as the radius of the ba

K. A. Al-Hassanieh, F. A. Reboredo, A. E. Feiguin, I. Gonzalez

We study the real-time dynamics of a pair hole/doubly-occupied-site, namely a holon and a doublon, in a 1D Hubbard insulator with on-site and nearest-neighbor Coulomb repulsion. Our analysis shows that the pair is long-lived and the expected decay mechanism to underlying spin excitations is actually inefficient. For a nonzero inter-site Coulomb repulsion, we

Hooman Shirani-Mehr, Giuseppe Caire

Channel state feedback schemes for the MIMO broadcast downlink have been widely studied in the frequency-flat case. This work focuses on the more relevant frequency selective case, where some important new aspects emerge. We consider a MIMO-OFDM broadcast channel and compare achievable ergodic rates under three channel state feedback schemes: analog feedback

Bruce Hughes

A new class of groups, the locally finitely determined groups of local similarities on compact ultrametric spaces, is introduced and it is proved that groups in this class have the Haagerup property (that is, they are a-T-menable in the sense of Gromov). The class includes Thompson&#39;s groups, which have already been shown to have the Haagerup property by

R. R. Gontsov, I. V. Vyugin

We give some additions to the article &#34;On the generalized Riemann-Hilbert problem with irregular singularities&#34; by Bolibruch, Malek, Mitschi (math/0410483). In particular, a weak GRH-problem and the GRH-problem for scalar differential equations are discussed.

Ralph Kaufmann

We give a brief summary of algebraic aspects of string theory arising in the noncommutative geometry setting of foliations called string diagrammatics which we introduced jointly with Bob Penner. We furthermore discuss how this gives rise to actions on the Hochschild complex of a Frobenius algebra. We then explain how this leads to new quantum chains for loo

Vasily E. Tarasov

Chains with long-range interactions are considered. The interactions are defined such that each nth particle interacts only with chain particles with the numbers n+a(m) and n-a(m), where m=1,2,3,... and a(m) is an integer-valued function. Exponential type functions a(m)=b^m, where b=2,3,.., are discussed. The correspondent pseudodifferential equations of cha

Jean-Michel Levy

The sample median is often used in statistical analyses of physical or astronomical data wherein a central value must be found from samples polluted by elements which do not belong to the population of interest or when the underlying probability law is such that the sample mean is useless for the stated purpose. Although it does not generally possesses the n

Juan Maria Garcia Lastra, Jakub W. Kaminski, Tomasz A. Wesolowski

A new approach to approximate the kinetic-energy-functional dependent component ($v_t[ρ_A,ρ_B](\vec{r})$) of the effective potential in one-electron equations for orbitals embedded in a frozen density environment (Eqs. 20-21 in [Wesolowski and Warshel, {\it J. Phys. Chem.} {\bf 97}, (1993) 8050]) is proposed. The exact limit for $v_t$ at $ρ_A\longrightarrow

Joao Marques-Silva, Ines Lynce, Vasco Manquinho

Symmetries are intrinsic to many combinatorial problems including Boolean Satisfiability (SAT) and Constraint Programming (CP). In SAT, the identification of symmetry breaking predicates (SBPs) is a well-known, often effective, technique for solving hard problems. The identification of SBPs in SAT has been the subject of significant improvements in recent ye

G. Ramos-Larios, M. A. Guerrero, L. F. Miranda

The planetary nebula NGC 6881 displays in the optical a quadrupolar morphology consisting of two pairs of highly collimated bipolar lobes aligned along different directions. An additional bipolar ejection is revealed by the hydrogen molecular emission, but its wide hourglass morphology is very different from that of the ionized material. To investigate in de

Nicolae Sandu

It is proved that any free Moufang loop can be embedded in a loop of invertible elements of some alternative algebra.

Henrik Strohmayer

Recently S.A. Merkulov established a link between differential geometry and homological algebra by giving descriptions of several differential geometric structures in terms of minimal resolutions of props. In particular he described the prop profile of Poisson geometry. In this paper we define a prop such that representations of its minimal resolution in a v

Andrew W. Steiner, Sanjay Reddy

{We calculate the neutrino emissivity of superfluid neutron matter in the inner crust of neutron stars. We find that neutrino emission due to fluctuations resulting from the formation of Cooper pairs at finite temperature is highly suppressed in non-relativistic systems. This suppression of the pair breaking emissivity in a simplified model of neutron matter

Juan Migliore, Uwe Nagel

If $V$ is an equidimensional codimension $c$ subscheme of an $n$-dimensional projective space, and $V$ is linked to $V&#39;$ by a complete intersection $X$, then we say that $V$ is {\em minimally linked} to $V&#39;$ if $X$ is a codimension $c$ complete intersection of smallest degree containing $V$. Gaeta showed that if $V$ is any arithmetically Cohen-Macaul

Adrian L. Melott

Essential equivalence of the conclusions of Romeo et al. (arXiv:0804.0294v1) with earlier work is pointed out. A possible general explanation for these conclusions is suggested.

Claus M. Sorensen

In this preprint, we explore a beautiful idea of Skinner and Wiles in the context of GSp(4) over a totally real field. The main result provides congruences between automorphic forms which are Iwahori-spherical at a certain place w, and forms with a tamely ramified principal series at w. Thus, after base change to a totally real finite solvable extension, one

Z. Shadman, H. Kampermann, T. Meyer, D. Bruss

We study eavesdropping in quantum key distribution with the six state protocol,when the signal states are mixed with white noise. This situation may arise either when Alice deliberately adds noise to the signal states before they leave her lab, or in a realistic scenario where Eve cannot replace the noisy quantum channel by a noiseless one. We find Eve&#39;s

Vasily E. Tarasov

Fractional derivative can be defined as a fractional power of derivative. The commutator (i/h)[H, ], which is used in the Heisenberg equation, is a derivation on a set of observables. A derivation is a map that satisfies the Leibnitz rule. In this paper, we consider a fractional derivative on a set of quantum observables as a fractional power of the commutat

Y. V. Kartashov, V. A. Vysloukh, A. Szameit, F. Dreisow

We address the properties of two-dimensional surface solitons supported by the interface of a waveguide array whose nonlinearity is periodically modulated. When the nonlinearity strength reaches its minima at the points where the linear refractive index attains its maxima, we found that nonlinear surface waves exist and can be made stable only within a limit

Alex Buchel, Lev Kofman

String theory compactification involves manifolds with multiple warp factors. For cosmological applications, one often introduces a short, high-energy inflationary throat, and a long,low-energy Standard Model throat. It is assumed that at the end of inflation,the excited Kaluza-Klein modes from the Inflationary throat tunnel to the SM throat and reheat Stand

Miroslav Bacak, Petr Hajek

The main result of the present note states that it is consistent with the ZFC axioms of set theory (relying on Martin&#39;s Maximum MM axiom), that every Asplund space of density character $ω_1$ has a renorming with the Mazur intersection property. Combined with the previous result of Jim\&#39; enez and Moreno (based upon the work of Kunen under the continuu

Jingpeng Li, Uwe Aickelin

Scheduling problems are generally NP-hard combinatorial problems, and a lot of research has been done to solve these problems heuristically. However, most of the previous approaches are problem-specific and research into the development of a general scheduling algorithm is still in its infancy. Mimicking the natural evolutionary process of the survival of th