March 2006 arXiv papers — page 32

Danilo E. Diaz, Harald Dorn

We explore the conjectured duality between the critical O(N) vector model and minimal bosonic massless higher spin (HS) theory in AdS. In the boundary free theory, the conformal partial wave expansion (CPWE) of the four-point function of the scalar singlet bilinear is reorganized to make it explicitly crossing-symmetric and closed in the singlet sector, dual

C. G. Bassa, M. H. van Kerkwijk, D. Koester, F. Verbunt

We present spectroscopic and photometric observations of the optical counterpart to PSR J1911-5958A, a millisecond pulsar located towards the globular cluster NGC 6752. We measure radial velocities from the spectra and determine the systemic radial velocity of the binary and the radial-velocity amplitude of the white-dwarf orbit. Combined with the pulsar orb

Qing Ou, Ying-Di Jin, Tao Zhou, Bing-Hong Wang

Many weighted scale-free networks are known to have a power-law correlation between strength and degree of nodes, which, however, has not been well explicated. We investigate the dynamic behaviors of resource/traffic flow on scale-free networks. The dynamical system will evolve to a kinetic equilibrium state, where the strength, defined by the amount of reso

A. S. de Wijn

In the study of chaotic behaviour of systems of many hard spheres, Lyapunov exponents of small absolute value exhibit interesting characteristics leading to speculations about connections to non-equilibrium statistical mechanics. Analytical approaches to these exponents so far can be divided into two groups, macroscopically oriented approaches, using kinetic

Thomas Fiedler

This paper has been withdrawn because the result turns out to be trivial.

George F R Ellis

Susskind claims in his recent book The Cosmic Landscape that evidence for the existence and nature of `pocket universes' in a multiverse would be available in the detailed nature of the Cosmic Blackbody Background Radiation that constantly bathes all parts of our observable universe. I point out that acceptance of the complex chain of argument involved d

Roland Omnes

This model was crazy (or not crazy enough for this topic) and it would lead to a reduction time much longer than the age of the universe.

Dragomir Z Djokovic, Konstanze Rietsch, Kaiming Zhao

Let F be an algebraically closed field of characteristic different from 2. We show that every nonsingular skew-symmetric n by n matrix X over F is orthogonally similar to a bidiagonal skew-symmetric matrix. In the singular case one has to allow some 4-diagonal blocks as well. If further the characteristic is 0, we construct the normal form for O_n(F)-similar

Ali Mostafazadeh

Analytic continuation of the classical dynamics generated by a standard Hamiltonian, H = p^2/2m + v(x), into the complex plane yields a particular complex classical dynamical system. For an analytic potential v, we show that the resulting complex system admits a description in terms of the phase space R^4 equipped with an unconventional symplectic structure.

L. Tolos, A. Ramos, E. Oset

The properties of the antikaons in nuclear matter are investigated from a chiral unitary approach which incorporates the s- and p-waves of the ${\bar K}N$ interaction. To obtain the in-medium meson-baryon amplitudes we include, in a self-consistent way, Pauli blocking effects, meson self-energies corrected by nuclear short-range correlations and baryon bindi

Pankaj Jain, John P. Ralston

We show that distances of objects at cosmological distances can be measured directly using interferometry. Our approach to interferometric parallax comes from analysis of 4-point amplitude and intensity correlations that can be generated from pairs of well-separated detectors. The baseline required to measure cosmological distances of Gigaparsec order are wi

Shuang-Qing Wu, Qing-Quan Jiang

Recent work that treats the Hawking radiation as a semi-classical tunnelling process from the four-dimensional Schwarzschild and Reissner-Nordstrom black holes is extended to the case of higher dimensional Reissner-Nordstrom-de Sitter black holes. The result shows that the tunnelling rate is related to the change of Bekenstein-Hawking entropy and the exact r

Mankei Tsang, Demetri Psaltis

Utilizing the underlying physics of evanescent wave amplification by a negative-refractive-index slab, it is shown that evanescent waves with specific spatial frequencies can also be amplified without any reflection simply by two dielectric planar waveguides. The simple configuration allows one to take advantage of the high resolution limit of a high-refract

Mankei Tsang

It is shown that optical pulses with a mean position accuracy beyond the standard quantum limit can be produced by adiabatically expanding an optical vector soliton followed by classical dispersion management. The proposed scheme is also capable of entangling positions of optical pulses and can potentially be used for general continuous-variable quantum info

Thomas Konstandin, Stephan J. Huber

We present an algorithm to analyze numerically the bounce solution of first-order phase transitions. Our approach is well suited to treat phase transitions with several fields. The algorithm consists of two parts. In the first part the bounce solution without damping is determined, in which case energy is conserved. In the second part the continuation to the

Sebastian F. Brandt, Axel Pelster, Ralf Wessel

We consider a model system of two coupled Hopfield neurons, which is described by delay differential equations taking into account the finite signal propagation and processing times. When the delay exceeds a critical value, a limit cycle emerges via a supercritical Hopf bifurcation. First, we calculate its frequency and trajectory perturbatively by applying

C. Aydin, M. Bayar, N. Kilic

Bounds on the anamolous magnetic moment of the tau neutrino are calculated through the reaction (e+e-)-->nunu(bar)gamma at the neutral boson pole and in the framework of an extended standard model, a left-right symmetric model and a superstring-inspired model which has one extra low-energy neutral gauge boson. The results are based

Stefano Viaggiu

We present a simple approach for obtaining Kerr interior solutions with the help of the Newman-Janis algorithm (NJA) starting with static space-times describing physically sensible interior Schwarzschild solutions. In this context, the Darmois-Israel (DI) junction conditions are analyzed. Starting from the incompressible Schwarzschild solution, a class of Ke

Nobuhiro Honda

In 1995 D. Joyce explicitly constructed a series of self-dual metrics with torus action on the connected sums of complex projective planes. In this paper we explicitly construct the twistor spaces of some of Joyce's self-dual metrics. Starting from a fiber space whose fibers are compact singular toric surfaces, we apply a number of birational transformat

Durdu Ö. Güney, David A. Meyer

We solve the Jaynes-Cummings Hamiltonian with time-dependent coupling parameters under dipole and rotating-wave approximation for a three-dimensional (3D) photonic crystal (PC) single mode cavity with a sufficiently high quality (Q) factor. We then exploit the results to show how to create a maximally entangled state of two atoms, and how to implement severa

Kentaro Nagamine, Jeremiah P. Ostriker, Masataka Fukugita, Renyue Cen

Taking three independent approaches, we investigate the simultaneous constraints set on the cosmic star formation history from various observations, including stellar mass density and extragalactic background light (EBL). We compare results based on: 1) direct observations of past light-cone, 2) a model using local fossil evidence constrained by SDSS observa

Stefan Papadima, Alexander I. Suciu

Bestvina-Brady groups arise as kernels of length homomorphisms from right-angled Artin groups G_\G to the integers. Under some connectivity assumptions on the flag complex Δ_\G, we compute several algebraic invariants of such a group N_\G, directly from the underlying graph \G. As an application, we give examples of Bestvina-Brady groups which are not isomor

Kohkichi Konno, Masumi Kasai

We present a general relativistic framework for studying gravitational effects in quantum mechanical phenomena. We concentrate our attention on the case of ultra-relativistic, spin-1/2 particles propagating in Kerr spacetime. The two-component Weyl equation with general relativistic corrections is obtained in the case of a slowly rotating, weak gravitational

Charles W. Misner, James R. van Meter, David R. Fiske

We study the numerical propagation of waves through future null infinity in a conformally compactified spacetime. We introduce an artificial cosmological constant, which allows us some control over the causal structure near null infinity. We exploit this freedom to ensure that all light cones are tilted outward in a region near null infinity, which allows us

Noah Snyder

Let G be a finite group of order n and V an irreducible representation over the complex numbers of dimension d. For some nonnegative number e, we have n=d(d+e). If e is small, then the character of V has unusually large degree. We fix e and attempt to classify such groups. For e<=3 we give a complete classification. For any other fixed e we show that there a

Wei Song, Yan Huang, Nai-Le Liu, Zeng-Bing Chen

We introduce the general catalysts for pure entanglement transformations under local operations and classical communications in such a way that we disregard the profit and loss of entanglement of the catalysts per se. As such, the possibilities of pure entanglement transformations are greatly expanded. Remarkably, we find an interesting phenomenon that, in s

Anton Öttl, Stephan Ritter, Michael Köhl, Tilman Esslinger

We present and characterize an experimental system in which we achieve the integration of an ultrahigh finesse optical cavity with a Bose-Einstein condensate (BEC). The conceptually novel design of the apparatus for the production of BECs features nested vacuum chambers and an in-vacuo magnetic transport configuration. It grants large scale spatial access to

Marcus Ruser

The dynamical Casimir effect for a massless scalar field in 1+1-dimensions is studied numerically by solving a system of coupled first-order differential equations. The number of scalar particles created from vacuum is given by the solutions to this system which can be found by means of standard numerics. The formalism already used in a former work is derive

Ali Mostafazadeh

We point out that T. Tanaka&#39;s recent criticism [quant-ph/0603075] of the results of J. Math. Phys. 43, 3944 (2002) [math-ph/0203005] is based on an assumption which was never made in the latter paper, namely that the diagonalizability of an operator implies that it is normal. Therefore, Tanaka&#39;s objections regarding this paper are not valid.

Sandro Wimberger, Andreas Buchleitner

We show that the quantum fidelity is accessible to cold atom experiments for a large class of evolutions in periodical potentials, properly taking into account the experimental initial conditions of the atomic ensemble. We prove analytically that, at the fundamental quantum resonances of the atom-optics kicked rotor, the fidelity saturates at a constant, tim

Nicolas Brunner, Valerio Scarani, Nicolas Gisin

We present bipartite Bell-type inequalities which allow the two partners to use some non-local resource. Such inequality can only be violated if the parties use a resource which is more non-local than the one permitted by the inequality. We introduce a family of N-inputs non-local machines, which are generalizations of the well-known PR-box. Then we construc

B. M. Breid, D. Witthaut, H. J. Korsch

It is well known that a particle in a periodic potential with an additional constant force performs Bloch oscillations. Modulating every second period of the potential, the original Bloch band splits into two subbands. The dynamics of quantum particles shows a coherent superposition of Bloch oscillations and Zener tunneling between the subbands, a Bloch-Zene

A. Kowalewska-Kudłaszyk, W. Leoński

We discuss a system comprising two nonlinear (Kerr-like) oscillators coupled mutually by a nonlinear interaction. The system is excited by an external coherent field that is resonant to the frequency of one of the oscillators. We show that the coupler evolution can be closed within a finite set of $n$-photon states, analogously as in the \textit{nonlinear qu

Mankei Tsang, Demetri Psaltis

The equations that govern the temporal evolution of two photons in the Schr{ö}dinger picture are derived, taking into account the effects of loss, group-velocity dispersion, temporal phase modulation, linear coupling among different optical modes, and four-wave mixing. Inspired by the formalism, we propose the concept of quantum temporal imaging, which uses

Wei Jiang, Qun-feng Chen, Yong-sheng Zhang, G. -C. Guo

In this paper, we report an experiment, which demonstrates computation of topological charges of two optical vortices via non-degenerate four-wave-mixing process. We show that the output signal beam carries orbital angular momentum which equals to the subtraction of the orbital angular momenta of the probe light and the backward pump light. The &#8312;&#8309

Jingfu Zhang, Xinhua Peng, Dieter Suter

Universal quantum information processing requires single-qubit rotations and two-qubit interactions as minimal resources. A possible step beyond this minimal scheme is the use of three-qubit interactions. We consider such three-qubit interactions and show how they can reduce the time required for a quantum state transfer in an XY spin chain. For the experime

Lars Bojer Madsen, Klaus Molmer

We present a general theoretical formalism to compute the fidelity of transformations of unknown quantum states. We then focus on the case of Gaussian transformations of continuous variable quantum systems, where, for the case of a Gaussian distribution of displaced coherent states, the theory is readily tractable by a covariance matrix formalism. We present

Deepak Dhar, Lov K. Grover, Shasanka M. Roy

We construct an algorithm for suppressing the transitions of a quantum mechanical system, initially prepared in a subspace P of the full Hilbert space of the system, to outside this subspace by subjecting it to a sequence of unequally spaced short-duration pulses. Each pulse multiplies the amplitude of the vectors in the subspace by -1. The number of pulses

Eric Brown, Guenter Ahlers

We present a broad range of measurements of the angular orientation theta_0(t) of the large-scale circulation (LSC) of turbulent Rayleigh-Benard convection as a function of time. We used two cylindrical samples of different overall sizes, but each with its diameter nearly equal to its height. The fluid was water with a Prandtl number of 4.38. The time series

Sohrab Rahvar

One of the questions in the cosmology courses is the cooling mechanism of cosmic fluid during it expansion according to classical concepts of the thermodynamics. In this short pedagogical paper, we quote the questions and give a natural approach dealing with this problem by measuring the dispersion velocity of the particles in the cosmic fluid by a comoving

V. Carbone, L. Sorriso-Valvo, A. Vecchio, F. Lepreti

Often in nature the temporal distribution of inhomogeneous stochastic point processes can be modeled as a realization of renewal Poisson processes with a variable rate. Here we investigate one of the classical examples, namely the temporal distribution of polarity reversals of the geomagnetic field. In spite of the commonly used underlying hypothesis, we sho

K. -H. Raedler, R. Stepanov

In an experiment in the Institute of Continuous Media Mechanics in Perm (Russia) an non--stationary screw dynamo is intended to be realized with a helical flow of liquid sodium in a torus. The flow is necessarily turbulent, that is, may be considered as a mean flow and a superimposed turbulence. In this paper the induction processes of the turbulence are inv

Ian Boutle, Richard H. S. Taylor, Rudolf A. Roemer

We study the dynamics of the El Nino phenomenon using the mathematical model of delayed-action oscillator (DAO). Topics such as the influence of the annual cycle, global warming, stochastic influences due to weather conditions and even off-equatorial heat-sinks can all be discussed using only modest analytical and numerical resources. Thus the DAO allows for

Victor Torres-Company, Jesus Lancis, Pedro Andres

The analysis of optical pulse generation by phase modulation of narrowband continuous-wave light, and subsequent propagation through a group-delay-dispersion circuit, is usually performed in terms of the so-called bunching parameter. This heuristic approach does not provide theoretical support for the electrooptic flat-top-pulse generation reported recently.

Martin Erik Horn

Analyses of interviews with secondary school students about their conceptions of light at the University of Potsdam indicate that numerous students have a deterministic view of light. With regard to these results the model of energy flow lines, which has been discussed recently in the didactical literature, is of special interest. Following this model, light

Alexei M. Tyryshkin, John J. L. Morton, Arzhang Ardavan, S. A. Lyon

Over the past 50 years, electron-nuclear double resonance (ENDOR) has become a fairly ubiquitous spectroscopic technique, allowing the study of spin transitions for nuclei which are coupled to electron spins. However, the low spin number sensitivity of the technique continues to pose serious limitations. Here we demonstrate that signal intensity in a pulsed

M. A. Fuentes, M. N. Kuperman, J. R. Iglesias

Different models to study the wealth distribution in an artificial society have considered a transactional dynamics as the driving force. Those models include a risk aversion factor, but also a finite probability of favoring the poorer agent in a transaction. Here we study the case where the partners in the transaction have a previous knowledge of the winnin

Edward Lyman, Daniel M. Zuckerman

We previously developed an algorithm, called resolution exchange, which improves canonical sampling of atomic resolution models by swapping conformations between high- and low-resolution simulations[1]. Here, we demonstrate a generally applicable incremental coarsening procedure and apply the algorithm to a larger peptide, met-enkephalin. In addition, we dem

Konstantin Yu. Bliokh, Yury P. Bliokh

We present a solution to the problem of reflection/refraction of a polarized Gaussian beam on the interface between two transparent media. The transverse shifts of the beams&#39; centers of gravity are calculated. They always satisfy the total angular momentum conservation law for beams, however, in general, do not satisfy the conservation laws for individua

Yongsheng Zhu

A definition for the statistical significance by constructing a correlation between the normal distribution integral probability and the p-value observed in an experiment is proposed, which is suitable for both counting experiment and continuous test statistics.

Bruce R. Barrett, Ionel Stetcu, Petr Navratil, James P. Vary

No-core shell model (NCSM) calculations using ab initio effective interactions are very successful in reproducing experimental nuclear spectra. The main theoretical approach is the use of effective operators, which include correlations left out by the truncation of the model space to a numerically tractable size. We review recent applications of the effectiv

L. S. Geng, J. Meng, H. Toki, W. H. Long

Following a systematic theoretical study of the ground-state properties of over 7000 nuclei from the proton drip line to the neutron drip line in the relativistic mean field model [Prog. Theor. Phys. 113 (2005) 785], which is in fair agreement with existing experimental data, we observe a few spurious shell closures, i.e. proton shell closures at Z=58 and Z=

Jian-You Guo, Zong-Qiang Sheng, Xiang-Zheng Fang

The microscopically constrained relativistic mean field theory is used to investigate the superdeformation for Pb isotopes. The calculations show that there exists a clear superdeformed minimum in the potential energy surfaces with four different interactions NL3, PK1, TM1 and NLSH. The excitation energy, deformation and depth of well in the superdeformed mi

V. Yu. Kozlov, N. Severijns, D. Beck, M. Beck

The WITCH experiment aims to study a possible admixture of a scalar or tensor type interaction in beta decay by determining the beta-neutrino angular correlation from the shape of the recoil energy spectrum. The installation period was completed and intensive commissioning of the set-up was performed already. The lay-out of the WITCH set-up and results of co

M. C. Depassier

Surface waves in a heated viscous fluid exhibit a long wave oscillatory instability. The nonlinear evolution of unidirectional waves is known to be described by a modified Korteweg-deVries-Kuramoto-Sivashinsky equation. In the present work we eliminate the restriction of unidirectional waves and find that the evolution of the wave is governed by a modified B

Dmitry Pelinovsky

Persistence of stationary and traveling single-humped localized solutions in the spatial discretizations of the nonlinear Schrodinger (NLS) equation is addressed. The discrete NLS equation with the most general cubic polynomial function is considered. Constraints on the nonlinear function are found from the condition that the second-order difference equation

M. Hnatic, M. Jurcisin, M. Stehlik

A quantum field model of helical MHD stochastically forced by gaussian hydrodynamic, magnetic and mixed noices is investigated. These helical noises lead to an exponential increase of magnetic fluctuations in the large scale range. Instabilities, which are produced in this process, are eliminated by spontaneous symmetry breaking mechanism accompanied by crea

Fumihiko Nakano

In this note we show that, a simple combination of deep results in the theory of random Schrödinger operators yields a quantitative estimate of the fact that the localization centers become far apart, as corresponding energies are close together.

Saugata Basu

In this paper we describe an algorithm that takes as input a description of a semi-algebraic set $S \subset \R^k$, defined by a Boolean formula with atoms of the form $P > 0, P < 0, P=0$ for $P \in {\mathcal P} \subset \R[X_1,...,X_k],$ and outputs the first $\ell+1$ Betti numbers of $S$, $b_0(S),...,b_\ell(S).$ The complexity of the algorithm is $(sd)^{k^{O

Andrey Pavlov

In the article is proved,that the complex part of the analytical continuation of the LL(Z(x)) on the negative axis is equal to cZ(x),c=const., were Z(x) is the odd function from the wide class of functions,L(Z(x)) is the transformation of Laplas.

Farhi Bakir

The first effective versions of Faltings product theorem are given by J.H. Evertse and R. Ferretti. Their results are improved quantitatively by P. Philippon, thanks to Samuel&#39;s multiplicity instead of the length in his zeros estimate. This version is a generalization of the usuel Roth&#39;s lemma on powers of the additive group. Here following this appr

Manoj Kumar Keshari

Let R be a Noetherian commutative ring of dimension n >2 and let A=R[T,T^{-1}]. Assume that the height of the Jacobson radical of R is atleast 2. Let P be a projective A-module of rank n=dim A - 1 with trivial determinant. We define an abelian group called the &#34;Euler class group of A&#34;, denoted by E(A). Let χbe an isomorphism from A to det(P). To the

Paul Fabel

Endowed with quotient topology inherited from the space of based loops, the fundamental group of the Hawaiian earring fails to be metrizable. The fundamental group of any space which retracts to the Hawaiian earring is also nonmetrizable.

Stephen J. Sangwine, Nicolas Le Bihan

We present a practical and efficient means to compute the singular value decomposition (svd) of a quaternion matrix A based on bidiagonalization of A to a real bidiagonal matrix B using quaternionic Householder transformations. Computation of the svd of B using an existing subroutine library such as lapack provides the singular values of A. The singular vect

François Delarue, Stéphane Menozzi

We propose a time-space discretization scheme for quasi-linear parabolic PDEs. The algorithm relies on the theory of fully coupled forward--backward SDEs, which provides an efficient probabilistic representation of this type of equation. The derivated algorithm holds for strong solutions defined on any interval of arbitrary length. As a bypass product, we ob

Saugata Basu, Richard Pollack, Marie-Francoise Roy

In this paper we describe a singly exponential algorithm for computing the first Betti number of a given semi-algebraic set. Singly exponential algorithms for computing the zero-th Betti number, and the Euler-Poincaré characteristic, were known before. No singly exponential algorithm was known for computing any of the individual Betti numbers other than the

Marcos Jardim, Rosa M. Miró-Roig

We show that instanton bundles of rank $r\le 2n-1$, defined as the cohomology of certain linear monads, on an $n$-dimensional projective variety with cyclic Picard group are semistable in the sense of Mumford-Takemoto. Furthermore, we show that rank $r\le n$ linear bundles with nonzero first Chern class over such varieties are stable. We also show that these

Anna Oneto, Elsa Zatini

Let R be a one-dimensional local Noetherian domain, which is supposed analytically irreducible and residually rational, and let I be a proper ideal of R. Our purpose is to study the two numbers l(I^*/R)-l(R/I) and rl(R/I)-l(I^*/R) (l denotes the length, r the Cohen-Macaulay type) already considered in the literature under various points of view. The basic id

Anna Oneto, Elsa Zatini

Let I be an m-primary ideal of a one-dimensional, analytically irreducible and residually rational local Noetherian domain R. Given the blowing-up of R along I we establish connections between the type-sequence of R and classical invariants like multiplicity, genus and reduction exponent of I.

Satoshi Mochizuki

In the paper M. Somekawa, {\it{On Milnor $K$-groups attached at semi-Abelian varieties}}, K-theory, \textbf{4} (1990) p.105, Somekawa conjectures that his Milnor K-group $K(k,G_1,...,G_r)$ attached to semi-abelian varieties $G_1$,...,$G_r$ over a field $k$ is isomorphic to ${\rm Ext}_{\mathcal{M}_k}^r(\mathbb{Z},G_1[-1] \otimes ... \otimes G_r[-1])$ where $\

A. G. Ramm

If $F:H\to H$ is a map in a Hilbert space $H$, $F\in C^2_{loc}$, and there exists $y$, such that $F(y)=0$, $F&#39;(y)\not= 0$, then equation $F(u)=0$ can be solved by a DSM (dynamical systems method). This method yields also a convergent iterative method for finding $y$, and converges at the rate of a geometric series. It is not assumed that $y$ is the only

Mariya Vorobets, Yaroslav Vorobets

We prove that three automorphisms of the rooted binary tree defined by a certain 3-state automaton generate a free non-Abelian group of rank 3.

Hanne Schultz

S. Artstein, K. Ball, F. Barthe, and A. Naor have shown that if (X_j) are i.i.d. random variables, then the entropy of n^{-1/2}(X_1+....+X_n) increases as n increases. The free analogue was recently proven by D. Shlyakhtenko. That is, if (x_j) are freely independent, identically distributed, self-adjoint elements in a noncommutative probability space, then t

Hossein Movasati, Evelina Viada

The paper is withdrawn.

Rainer Siegmund-Schultze, Heinrich von Weizsaecker

In part I (math.PR/0406392) we proved for an arbitrary one-dimensional random walk with independent increments that the probability of crossing a level at a given time n is of the maximal order square root of n. In higher dimensions we call a random walk &#39;polygonally recurrent&#39; (resp. transient) if a.s. infinitely many (resp. finitely many) of the st

Rainer Siegmund-Schultze, Heinrich von Weizsaecker

We prove for an arbitrary one-dimensional random walk with independent increments that the probability of crossing a level at a given time n has the order of square root of n. Moment or symmetry assumptions are not necessary. In removing symmetry the (sharp) inequality P(|X+Y| <= 1) < 2 P(|X-Y| <= 1) for independent identically distributed X,Y is used. In pa

Jean Bourgain, Nets Katz, Terence Tao

Let $A$ be a subset of a finite field $F := \Z/q\Z$ for some prime $q$. If $|F|^δ< |A| < |F|^{1-δ}$ for some $δ> 0$, then we prove the estimate $|A+A| + |A.A| \geq c(δ) |A|^{1+\eps}$ for some $\eps = \eps(δ) > 0$. This is a finite field analogue of a result of Erdos and Szemeredi. We then use this estimate to prove a Szemeredi-Trotter type theorem in finite

Volker Braun, Burt A. Ovrut

It is shown that strongly coupled heterotic M-theory with anti-five-branes in the S^1/Z_2 bulk space can have meta-stable vacua which break N=1 supersymmetry and have a small, positive cosmological constant. This is demonstrated for the &#34;minimal&#34; heterotic standard model. This vacuum has the exact MSSM matter spectrum in the observable sector, a triv

Axel Maas

During the last years significant progress has been made in the understanding of the confinement of quarks and gluons. However, this progress has been made in two directions, which are at first sight very different. On the one hand, topological configurations seem to play an important role in the formation of the static quark-anti-quark potential. On the oth

Manfred Herbst, Wolfgang Lerche, Dennis Nemeschansky

We first determine and then study the complete set of non-vanishing A-model correlation functions associated with the ``long-diagonal branes&#39;&#39; on the elliptic curve. We verify that they satisfy the relevant A-infinity consistency relations at both classical and quantum levels. In particular we find that the A-infinity relation for the annulus provide

G. Bonelli, L. Bonora, A. Ricco

In this letter we study topological open string field theory on D--branes in a IIB background given by non compact CY geometries ${\cal O}(n)\oplus{\cal O}(-2-n)$ on $\P1$ with a singular point at which an extra fiber sits. We wrap $N$ D5-branes on $\P1$ and $M$ effective D3-branes at singular points, which are actually D5--branes wrapped on a shrinking cycl

S. Moretti, S. Munir

The NMSSM contains a Higgs singlet in addition to the two Higgs doublets typical of the MSSM, thus resulting in a total of seven physical Higgs mass states. Therefore, the phenomenology of the NMSSM Higgs sector can vary considerably from that of the MSSM and there are good prospects of finding in regions of the NMSSM parameter space Higgs signals that canno

J. J. van der Bij

In this letter I discuss a class of extensions of the standard model that have a minimal number of possible parameters, but can in principle explain dark matter and inflation. It is pointed out that the so-called new minimal standard model contains a large number of parameters that can be put to zero, without affecting the renormalizability of the model. Wit

M. B. Voloshin

A threshold singularity in a heavier meson channel, e.g. $D^* {\bar D}^*$, generally reflects in the amplitudes of $e^+e^-$ annihilation into lighter meson pairs, such as $D^* {\bar D}$, $D {\bar D}$, and $D_s {\bar D}_s$, due to the channel coupling. The behavior of the cross section of the $e^+e^-$ annihilation into each channel in this situation is consid

L3 Collaboration

Hadron production and lepton-pair production in e+e- collisions are studied with data collected with the L3 detector at LEP at centre-of-mass energies sqrt{s}=192-208GeV. Using a total integrated luminosity of 453/pb, 36057 hadronic events and 12863 lepton-pair events are selected. The cross sections for hadron production and lepton-pair production are measu

2 Collaboration, V. M. Aulchenko

The cross section for the process $e^+e^-\toπ^+π^-$ is measured in the c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events including 860000 $e^+e^-$ events, 82000 $μ^+μ^-$ events, and 33000 $π^+π^-$ events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2-4.2 and 5-13%, respectively.

Luc Blanchet

Thanks to the new generation of gravitational wave detectors LIGO and VIRGO, the theory of general relativity will face new and important confrontations to observational data with unprecedented precision. Indeed the detection and analysis of the gravitational waves from compact binary star systems requires beforehand a very precise solution of the two-body p

William Perkins

This paper analyzes the performance of Kak&#39;s three stage quantum cryptographic protocol based on public key cryptography against a man-in-the-middle attack. A method for protecting against such an attack is presented using certificates distributed by a trusted third party.

Balaji Nedurumalli

This article considers the question of the teleportation protocol from an engineering perspective. The protocol ideally requires an authority that ensures that the two communicating parties have a perfectly entangled pair of particles available to them. But this cannot be unconditionally established to the satisfaction of the parties due to the fact that an

Mihai Patrascu, Mikkel Thorup

We develop a new technique for proving cell-probe lower bounds for static data structures. Previous lower bounds used a reduction to communication games, which was known not to be tight by counting arguments. We give the first lower bound for an explicit problem which breaks this communication complexity barrier. In addition, our bounds give the first separa

G. Lawes, B. Melot, K. Page, C. Ederer

We have investigated the structural, magnetic, thermodynamic, and dielectric properties of polycrystalline CoCr$_2$O$_4$, an insulating spinel exhibiting both ferrimagnetic and spiral magnetic structures. Below $T_c$ = 94 K the sample develops long-range ferrimagnetic order, and we attribute a sharp phase transition at $T_N$ $\approx$ 25 K with the onset of

Aleksey N. Kolmogorov, Stefano Curtarolo

Modern compound prediction methods can efficiently screen large numbers of crystal structure phases and direct the experimental search for new materials. One of the most challenging problems in alloy theory is the identification of stable phases with a never seen prototype; such predictions do not always follow rational strategies. While performing ab initio

Hong-Yi Chen, Lingyin Zhu, C. S Ting

The local differential tunneling conductance on a Zn impurity in a disordered d-wave superconductors is studied. Quantum interference between many impurities leads to definitive quasiparticle spectra. We suggest that an elaborate analysis on impurity-induced spectra with quantum interference effect included may be able to pin down the sign and strength of th

Z. A. Daya, E. Ben-Naim, R. E. Ecke

We report an experimental study of the statistical properties of vibrated granular rings. In this system, a linked rod and bead metallic chain in the form of a ring is collisionally excited by a vertically oscillating plate. The dynamics are driven primarily by inelastic bead-plate collisions and are simultaneously constrained by the rings&#39; physical conn

Da Gao, Asok K. Ray

The electronic properties of bulk fcc americium and the (111) surface have been investigated with the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K suite of programs. The study is carried out for the anti-ferromagnetic ground state of Am at different levels of theory: (1) scalar-relativity vs. full-relativity; (

Paul Maragakis, Martin Spichty, Martin Karplus

We derive the optimal estimates of the free energies of an arbitrary number of thermodynamic states from nonequilibrium work measurements; the work data are collected from forward and reverse switching processes and obey a fluctuation theorem. The maximum likelihood formulation properly reweights all pathways contributing to a free energy difference, and is

Alejandro B. Kolton, Alberto Rosso, Thierry Giamarchi, Werner Krauth

We study the steady-state low-temperature dynamics of an elastic line in a disordered medium below the depinning threshold. Analogously to the equilibrium dynamics, in the limit T->0, the steady state is dominated by a single configuration which is occupied with probability one. We develop an exact algorithm to target this dominant configuration and to analy

L. Meier, G. Salis, C. Ellenberger, E. Gini

Electron spins in an InGaAs semiconductor quantum well are used as a magnetometer of magnetic stray-fields from patterned Fe stripes. Using time-resolved Faraday rotation, the coherent precession of quantum-well spins in the inhomogeneous field below the Fe stripes is measured for varying magnetic fields. Comparing with reference stripes made of Au, we find

Santiago Gil, Damian H. Zanette

We study a stochastic model for the coevolution of a process of opinion formation in a population of agents and the network which underlies their interaction. Interaction links can break when agents fail to reach an opinion agreement. The structure of the network and the distribution of opinions over the population evolve towards a state where the population

Q. Mistral, Joo-Von Kim, T. Devolder, P. Crozat

We study the current and temperature dependences of the microwave voltage emission of spin-valve nanopillars subjected to an in-plane magnetic field and a perpendicular-to-plane current. Despite the complex multilayer geometry, clear microwave emission is shown to be possible and spectral lines as narrow as 3.8 MHz (at 150 K) are observed.