March 2002 arXiv papers — page 14

S. Pilgram, M. Buttiker

We consider a mesoscopic measuring device whose conductance is sensitive to the state of a two-level system. The detector is described with the help of its scattering matrix. Its elements can be used to calculate the relaxation and decoherence time of the system, and determine the characteristic time for a reliable measurement. We derive conditions needed fo

S. H. Tessmer, G. Finkelstein, P. I. Glicofridis, R. C. Ashoori

Subsurface Charge Accumulation imaging is a cryogenic scanning probe technique that has recently been used to spatially probe incompressible strips formed in a two-dimensional electron system (2DES) at high magnetic fields. In this paper, we present detailed numerical modeling of these data. At a basic level, the method produces results that agree well with

K. Kinemuchi, H. A. Smith, A. LaCluyze, C. L. Clark

We present new results on RR Lyrae stars and anomalous Cepheids in the Draco dwarf spheroidal galaxy. We have increased the number of double-mode RR Lyrae stars and found three new anomalous Cepheids. With period-magnitude and period-amplitude diagrams, we discuss the Oosterhoff classification of Draco. Contradictory results were found in that Draco appears

S. Gardner

Direct CP violation can exist in untagged, neutral B-meson decays to certain self-conjugate, hadronic final states. It can occur if the resonances which appear therein permit the identification of distinct, CP-conjugate states -- in analogy to stereochemistry, we term such states ``CP-enantiomers.'' These states permit the construction of a CP-odd am

U. Welp, G. Karapetrov, W. K. Kwok, G. W. Crabtree

The superconducting phase diagram of MgB2 was determined from magnetization, magneto-transport and the first single-crystal specific heat measurements. A zero-temperature in-plane coherence length of 8 nm is determined. The superconducting anisotropy increases from a value around 2 near Tc to above 4.5 at 22 K. For H||c a pronounced peak effect in the critic

Riccardo Capovilla, Jemal Guven

The adhesion of a lipid membrane vesicle to a fixed substrate is examined from a geometrical point of view. This vesicle is described by the Helfrich hamiltonian quadratic in mean curvature; it interacts by contact with the substrate, with an interaction energy proportional to the area of contact. We identify the constraints on the geometry at the boundary o

M. G. Payne, L. Deng

We show both analytically and numerically that photons from a probe pulse are not stored in several recent experiments. Rather, they are absorbed to produce a two-photon excitation. More importantly, when an identical coupling pulse is re-injected into the medium, we show that the regenerated optical field has a pulse width that is very different from the or

Eric Agol, Marc Kamionkowski, Leon Koopmans, Roger Blandford

The MACHO and OGLE collaborations have argued that the three longest duration bulge microlensing events are likely caused by nearby black holes, given the small velocities measured with microlensing parallax and nondetection of the lenses. However, these events may be due to lensing by more numerous lower mass stars at greater distances. We find a posteriori

Philip Boalch

For each connected complex reductive group G, we find a family of new examples of complex quasi-Hamiltonian G-spaces with G-valued moment maps. These spaces arise naturally as moduli spaces of (suitably framed) meromorphic connections on principal G-bundles over a disc, and they generalise the conjugacy class example of Alekseev, Malkin and Meinrenken (which

Vicente Azcoiti, Giuseppe Di Carlo, Angelo Galante, Victor Laliena

We propose a new approach to perform numerical simulations of theta-vacuum like systems, test it in two analytically solvable models, and apply it to CP^3. The main new ingredient in our approach is the method used to compute the probability distribution function of the topological charge at theta=0. We do not get unphysical phase transitions (flattening beh

Paul Halpern

We solve the five dimensional vacuum Einstein equations for several kinds of anisotropic geometries. We consider metrics in which the spatial slices are characterized as Bianchi types-II and V, and the scale factors are dependent both on time and a non-compact fifth coordinate. We examine the behavior of the solutions we find, noting for which parameters the

Giulio Casati, Tomaz Prosen

We provide firm convincing evidence that the energy transport in a one-dimensional gas of elastically colliding free particles of unequal masses is anomalous, i.e. the Fourier Law does not hold. Our conclusions are based on the analysis of the dependence of the heat current on the number of particles, of the internal temperature profile and on the Green-Kubo

Shan-Wen Tsai, P. J. Hirschfeld

The current response of a d-wave superconductor containing a single impurity is calculated and shown to be singular in the low-temperature limit, leading in the case of strong scattering to a 1/T term in the penetration depth $λ(T)$ similar to that induced by Andreev surface bound states. For a small number of such impurities, we argue this low-$T$ upturn co

Alejandro Perez

The goal of this work is two-fold. In the first part of this paper we regard classical Plebanski's action as a BF action supplemented by constraints. We introduce a spin foam model for Riemannian general relativity by systematically implementing these constraints as restrictions on paths in the state-sum of the BF theory. The spin foam model obtained is

Elena D'Onghia, Claudio Firmani, Guido Chincarini

We propose a new numerical procedure to simulate a single dark halo of any size and mass in a hierarchical framework coupling the extended Press-Schechter formalism (EPSF) to N-body simulations. The procedure consists of assigning cosmological initial conditions to the particles of a single halo with a EPSF technique and following only the dynamical evolutio

Frank Verstraete, Henri Verschelde

We consider a single copy of a mixed state of two qubits and show how its fidelity or maximal singlet fraction is related to the entanglement measures concurrence and negativity. We characterize the extreme points of the convex set of states with constant fidelity, and use this to prove tight lower and upper bounds on the fidelity for a given amount of entan

C. M. Hull

Generalised Scherk-Schwarz reductions in which compactification on a circle is accompanied by a twist with an element of a global symmetry G typically lead to gauged supergravities and are classified by the monodromy matrices, up to conjugation by the global symmetry. For compactifications of IIB supergravity on a circle, G=SL(2,R) and there are three distin

John Franks, Michael Handel

Suppose G is an almost simple group containing a subgroup isomorphic to the three-dimensional integer Heisenberg group. For example any finite index subgroup of SL(3,Z) is such a group. The main result of this paper is that every action of G on a closed oriented surface by area preserving diffeomorphisms factors through a finite group.

Charles Tahan, Mark Friesen, Robert Joynt

Direct phonon spin-lattice relaxation of an electron qubit bound by a donor impurity or quantum dot in SiGe heterostructures is investigated. The aim is to evaluate the importance of decoherence from this mechanism in several important solid-state quantum computer designs operating at low temperatures. We calculate the relaxation rate $1/T_1$ as a function o

A. Banfi, G. Marchesini, G. Smye

We introduce the azimuthal correlation for the deep inelastic scattering process. We present the QCD prediction to the level of next-to-leading log resummation, matching to the fixed order prediction. We also estimate the leading non-perturbative power correction. The observable is compared with the energy-energy correlation in e+e- annihilation, on which it

Donam Youm

We examine whether the cosmologies with varying speed of light (VSL) are compatible with the second law of thermodynamics. We find that the VSL cosmology with varying fundamental constant is severely constrained by the second law of thermodynamics, whereas the bimetric cosmological models are less constrained.

Rocco Duvenhage

A suitable unified statistical formulation of quantum and classical mechanics in a *-algebraic setting leads us to conclude that information itself is noncommutative in quantum mechanics. Specifically we refer here to an observer's information regarding a physical system. This is seen as the main difference from classical mechanics, where an observer&#39

Alessandro Speranza, Peter Sollich

Polydispersity is believed to have important effects on the formation of liquid crystal phases in suspensions of rod-like particles. To understand such effects, we analyse the phase behaviour of thin hard rods with length polydispersity. Our treatment is based on a simplified Onsager theory, obtained by truncating the series expansion of the angular dependen

Andrew E. Firth, Ofer Lahav, Rachel S. Somerville

A new approach to estimating photometric redshifts - using Artificial Neural Networks (ANNs) - is investigated. Unlike the standard template-fitting photometric redshift technique, a large spectroscopically-identified training set is required but, where one is available, ANNs produce photometric redshift accuracies at least as good as and often better than t

M. Granath, S. Ostlund

We derive a model for the highest occupied molecular orbital band of a C60 crystal which includes on-site electron-electron interactions. The form of the interactions are based on the icosahedral symmetry of the C60 molecule together with a perturbative treatment of an isolated C60 molecule. Using this model we do a mean-field calculation in two dimensions o

N. M. Bogoliubov, A. G. Pronko, M. B. Zvonarev

We consider the six-vertex model on an $N \times N$ square lattice with the domain wall boundary conditions. Boundary one-point correlation functions of the model are expressed as determinants of $N\times N$ matrices, generalizing the known result for the partition function. In the free fermion case the explicit answers are obtained. The introduced correlati

ALEPH Collaboration

A total of 628$\invpb$ of data collected with the ALEPH detector at centre-of-mass energies from 189 to 209 GeV is analysed in the search for gauge mediated SUSY breaking (GMSB) topologies. These topologies include two acoplanar photons, non-pointing single photons, acoplanar leptons, large impact parameter leptons, detached slepton decay vertices, heavy sta

Borut Paul Kersevan, Elzbieta Richter-Was

The W b anti-b, Z b anti-b and t anti-t b anti-b production at LHC are irreducible backgrounds for possible observability of the Standard Model (SM) and Minimal Supersymmetric Standard Model (MSSM) light Higgs boson respectively in the associated WH, ZH and t anti-t H production followed by the H -> b anti-b decay. We present a comparison of the background e

S. Wallentowitz

A quantum theory of feedback of bosonic many-atom systems is formulated. The feedback-induced many-atom correlations are treated by use of a parameterized correlation function, for which closed equations of motion are derived. Therefrom the dynamics of any additive property of the system, i.e., properties derived from the reduced single-atom density operator

Gernot Schaller, Ralf Schützhold, Günter Plunien, Gerhard Soff

The phenomenon of particle creation within a resonantly vibrating lossy cavity is investigated for the example of a massless scalar field at finite temperature. Leakage is provided by insertion of a dispersive mirror into a larger ideal cavity. Via the rotating wave approximation we demonstrate that for the case of parametric resonance the exponential growth

I. P. Lokhtin, L. I. Sarycheva, A. M. Snigirev

The azimuthal anisotropy of jet spectra due to energy loss of jet partons in azimuthally non-symmetric volume of dense quark-gluon matter is considered for semi-central nuclear interactions at collider energies. We develop the techniques for event-by-event analysing the jet azimuthal anisotropy using particle and energy elliptic flow, and suggest a method fo

Raul Cordovil, David Forge

Let A be a (central) arrangement of hyperplanes in a finite dimension complex vector space V. Let M(A) be the dependence matroid determined by A. The Orlik-Solomon algebra OS(M) of a matroid M is the exterior algebra on the points modulo the ideal generated by circuit boundaries. The algebra OS(M) is isomorphic to the cohomology algebra of the complement in

Subir Ghosh

In an alternative interpretation, the Seiberg-Witten map is shown to be induced by a field dependent co-ordinate transformation connecting noncommutative and ordinary space-times. Furthermore, following our previous ideas, it has been demonstrated here that the above (field dependent co-ordinate) transformation can occur naturally in the Batalin-Tyutin exten

M. Fujita, H. Goka, K. Yamada, M. Matsuda

We report the results of elastic neutron scattering measurements performed on 1/8-hole doped La$_{1.875}$Ba$_{0.125-x}$Sr$_{x}$CuO$_{4}$ single crystals with {\it x}=0.05, 0.06, 0.075 and 0.085. In the low-temperature less-orthorhombic (LTLO, {\it Pccn} symmetry) phase, the charge-density-wave (CDW) and spin-density-wave (SDW) wavevectors were found to tilt

Donald Marolf, Carlo Rovelli

Does the measurement of a quantum system necessarily break Lorentz invariance? We present a simple model of a detector that measures the spacetime localization of a relativistic particle in a Lorentz invariant manner. The detector does not select a preferred Lorentz frame as a Newton-Wigner measurement would do. The result indicates that there exists a Loren

Norisuke Sakai, Ryo Sugisaka

Non-supersymmetric multi-wall configurations are generically unstable. It is proposed that the stabilization in compact space can be achieved by introducing a winding number into the model. A BPS-like bound is studied for the energy of configuration with nonvanishing winding number. Winding number is implemented in an ${\cal N}=1$ supersymmetric nonlinear si

Shin Ishida, Muneyuki Ishida

Starting from the multi-local Klein-Gordon equations with Lorentz-scalar squared-mass operator we give a covariant quark representation of the general composite mesons and baryons with definite Lorentz transformation property. The phenomenologically observed hadron mass spectra is pointed out to satisfy possibly the approximate symmetry under the tilde U(4)

A. A. Bichl, M. Ertl, A. Gerhold, J. M. Grimstrup

The quantization of the non-commutative N=1, U(1) super-Yang-Mills action is performed in the superfield formalism. We calculate the one-loop corrections to the self-energy of the vector superfield. Although the power-counting theorem predicts quadratic ultraviolet and infrared divergences, there are actually only logarithmic UV and IR divergences, which is

I. N. Filikhin, A. Gal

New Faddeev-Yakubovsky calculations are reported for Lambda-Lambda-6He and Lambda-Lambda-10Be in terms of clusters of alpha's and Lambda's, using Lambda-Lambda s-wave potentials motivated by several of the Nijmegen model interactions. The self consistency of the Lambda-Lambda hypernuclear world data for these species is discussed. The newly reported

Kazuo Fujikawa, Masato Ishibashi, Hiroshi Suzuki

The CP symmetry is not manifestly implemented for the local and doubler-free Ginsparg-Wilson operator in lattice chiral gauge theory. We precisely identify where the effects of this CP breaking appear. We show that they appear in: (I) Overall constant phase of the fermion generating functional. (II) Overall constant coefficient of the fermion generating func

Masanori Asakura, Shuji Saito

The contents is changed.

M. Fujita, T. Kubo, S. Kuroshima, T. Uefuji

We have investigated the magnetism and the superconductivity of an electron-doped Pr$_{1-x}$LaCe$_{x}$CuO$_{4}$ (PLCCO) using single crystal and powder samples by means of zero-field muon spin rotation/relaxation (ZF-$μ$SR) and magnetic susceptibility measurements. Muon spin rotation corresponding to antiferromagnetic (AF) order was observed in the sample wi

A. K. H. Kong, M. R. Garcia, F. A. Primini, S. S. Murray

We report on \chandra observations of the central region of M31. By combining eight \chandra ACIS-I observations taken between 1999 and 2001, we have identified 204 X-ray sources within the central $\sim 17'\times17'$ region of M31, with a detection limit of $\sim 2\times10^{35}$\lum. Of these 204 sources, 22 are identified with globular clusters, 2

Jeremy Michelson

The maximally supersymmetric type IIB pp-wave is compactified on spatial circles, with and without an auxiliary rotational twist. All spatial circles of constant radius are identified. Without the twist, an S$^1$ compactification can preserve 24, 20 or 16 supercharges. $T^2$ compactifications can preserve 20, 18 or 16 supercharges; $T^3$ compactifications ca

M. G. Payne, L. Deng

We investigate a four-state system interacting with long and short laser pulses in a weak probe beam approximation. We show that when all lasers are tuned to the exact unperturbed resonances, part of the four-wave mixing (FWM) field is strongly absorbed. The part which is not absorbed has the exact intensity required to destructively interfere with the excit

C. P. Sun, S. Yi, L. You

We investigate the decoherence of a superposition of symmetric collective internal states of an atomic ensemble due to inhomogeneous coupling to external control fields. For asymptotically large system, we find the characteristic decoherence rate scales as $\sqrt{N}$ with $N$ being the total number of atoms. Our results shed new light on attempts for quantum

V. S. Starovoitov

The shape and the inverse participation ratio (IPR) of local spectral density (LSD) are studied for a generic isolated system of coupled quantum states, the Hamiltonian of which is represented by a band random matrix with the disordered leading diagonal. We find for the matrices with arbitrary small band that the lack of ergodicity for LSD can be associated

R. T. Thew, S. Tanzilli, W. Tittel, H. Zbinden

We experimentally investigate the robustness of maximal and non-maximal Time-Bin entangled photons over distances up to 11 km. The entanglement is determined by controllable parameters and in all cases is shown to be robust, in that the photons maintain their degree of entanglement after transmission.

Richard B. Kassman, Gennady P. Berman, Vladimir I. Tsifrinovich, Gustavo V. Lopez

We discuss the implementation of quantum logic in a system of strongly interacting particles. The implementation is qubitless since ``logical qubits'' don't correspond to any physical two-state subsystems. As an illustration, we present the results of simulations of the quantum controlled-NOT gate and Shor's algorithm for a chain of spin-1/2

Ignacio R. Solá, Vladimir S. Malinovsky

We show that a counter-intuitive pulse sequence leads to adiabatic passage between the vibrational levels of three harmonic potentials through parallel dark states in adiabatic approximation. However, the adiabatic assumptions break down for very intense pulses and non-adiabatic couplings result in the population transfer by light-induced potential shaping.

Gunnar Hornig, Christoph Mayer

An expression for a third-order link integral of three magnetic fields is presented. It is a topological invariant and therefore an invariant of ideal magnetohydrodynamics. The integral generalizes existing expressions for third-order invariants which are obtained from the Massey triple product, where the three fields are restricted to isolated flux tubes. T

A. J. Turski, B. Atamaniuk, E. Turska

Fundamental rules and definitions of Fractional Differintegrals are outlined. Factorizing 1-D and 2-D Helmholtz equations four fractional eigenfunctions are determined. The functions exhibit incident and reflected plane waves as well as diffracted incident and reflected waves of the half-plane edge. They allow to construct the Sommerfeld half-plane diffracti

Li-Bin Fu, Jie Liu, Shi-Gang Chen, Yi-Shi Duan

In the $ϕ$-mapping theory, the topological current constructed by the order parameters can possess different inner structure. The difference in topology must correspond to the difference in physical structure. The transition between different structures happens at the bifurcation point of the topological current. In a self-interaction two-level system, the c

Chiranjib Sur, Dipankar Chattarji

In this paper we have tried to establish a theory for angular correlation between the photo- and Auger electrons in the two-step double photoionization of a rare gas atom. The basic finding of this paper is that a general theoretical expression for the angular correlation function is established in the problem of double photoionization of atoms in the presen

Daniel Phillips

In these lectures I first explain, in a rather basic fashion, the construction of effective field theories. I then discuss some recent developments in the application of such theories to two- and three-nucleon systems.

A. Sibirtsev, S. Schneider, Ch. Elster, J. Haidenbauer

Very recent data for the reaction gamma+d ->eta np, namely total cross sections, angular and momentum spectra, are analyzed within a model that includes contributions from the impulse approximation and next order corrections due to the np and eta-N interactions in the final state. Comparison between the calculations and the new data indicate sizable contribu

Jacek Dobaczewski, Witold Nazarewicz

In years to come, we shall see substantial progress in our understanding of nuclear structure - a rich and many-faceted field. An important element in this task will be to extend the study of nuclei into new domains. The journey to 'the limits' of isospin, angular momentum, and mass and charge is a quest for new and unexpected phenomena which await u

J. Bartel, K. Bencheikh

Semiclassical expansions derived in the framework of the Extended Thomas-Fermi approach for the kinetic energy density tau(r) and the spin-orbit density J(r) as functions of the local density rho(r) are used to determine the central nuclear potentials V_n(r) and V_p(r) of the neutron and proton distribution for effective interactions of the Skyrme type. We d

J. L. Nagle, T. S. Ullrich

We present a written version of four lectures given at the NATO Advanced Study Institute on "CD Perspectives on Hot and Dense Matter"in Cargese, Corsica during August, 2001. Over the last year the first exciting results from the Relativistic Heavy Ion Collider (RHIC) and the four experiments BRAHMS, PHENIX, PHOBOS, and STAR have been presented. In th

T. Bartsch, J. Main, G. Wunner

Bifurcations of classical orbits introduce divergences into semiclassical spectra which have to be smoothed with the help of uniform approximations. We develop a technique to extract individual energy levels from semiclassical spectra involving uniform approximations. As a prototype example, the method is shown to yield excellent results for photo-absorption

H. Yamada

Phase-locked solutions of coupled oscillators are studied with asymmetric coupling strengths or inhomogeneous natural frequencies. The solutions show remarkable profiles of phase lags from the pacemaker corresponding to the ratio of upward and downward coupling strengths. By means of the existence condition of phase-locked solutions, the transition points fr

A. Iosevich, I. Laba

We prove that a well-distributed subset of R^2 can have a separated distance set only if the distance is induced by a polygon.

Dominic Joyce

The exceptional holonomy groups are G2 in 7 dimensions, and Spin(7) in 8 dimensions. Riemannian manifolds with these holonomy groups are Ricci-flat. This is a survey paper on constructions for compact 7- and 8-manifolds with holonomy G2 and Spin(7). The simplest such constructions work by using techniques from complex geometry and Calabi-Yau analysis to reso

Matias Graña

We classify indecomposable racks of order p^2 (p a prime). There are 2p^2 - 2p - 2 isomorphism classes, among which 2p^2 - 3p - 1 correspond to quandles. In particular, we prove that an indecomposable quandle of order p^2 is affine (=Alexander). One of the results yielding this classification is the computation of the quandle nonabelian second cohomology gro

Magnus Carlehed, Jan Wiegerinck

Les fonctions plurisousharmoniques negatives dans un domaine D de \CC^n forment un cone convexe. Nous considerons les points extremaux de ce cone, et donnons trois exemples. En particulier, nous traitons le cas de la fonction de Green pluricomplexe. Nous calculons celle du bidisque, lorsque les poles se situent sur un axe. Nous montrons que cette fonction ne

Petre Birtea, Mircea Puta, Tudor S. Ratiu, Razvan Tudoran

We will prove the presence of chaotic motion in the Lorenz five-component atmospheric system model using the Melnikov function method developed by Holmes and Marsden for Hamiltonian systems on Lie Groups.

Baohua Fu

In this note, firstly we give an easy proof of the factorization of symmetric matrices (see [Mos] math-ph/0203023), then we use it to prove the well-known fact that the automorphism group of a non-degenerate symmetric bilinear form acts transitively on the locus of isotropic subspaces Σ_k.

Petre Birtea, Mircea Puta, Tudor S. Ratiu

Sufficient conditions for the controllability of a conservative reduced system are given. Several examples illustrating the theory are also presented.

Jacek Chadzynski, Tadeusz Krasinski

The paper gives a full description of the growth of the gradient of a polynomial in two complex variables at infinity near any fiber of the polynomial

David Bachman, Saul Schleimer

If a tangle, K, in the 3-ball has no planar, meridional, essential surfaces in its exterior then thin position for K has no thin levels.

Masanori Asakura, Shuji Saito

In this paper, we develop the theory of Jacobian rings of open complete intersections, which mean a pair $(X,Z)$ where $X$ is a smooth complete intersection in the projective space and and $Z$ is a simple normal crossing divisor in $X$ whose irreducible components are smooth hypersurface sections on $X$. Our Jacobian rings give an algebraic description of th

Oleg I. Reinov

A. Szankowski's example is used to construct a Banach space similar to that of "An example of an asymptotically Hilbertian space which fails the approximation property", P.G. Casazza, C.L. Garc\'ıa, W.B. Johnson [math.FA/0006134 (math@arXiv.org)].

Hailiang Liu, Eitan Tadmor

We provide a complete description of the critical threshold phenomena for the two-dimensional localized Euler-Poisson equations, introduced by the authors in [Liu & Tadmor, Comm. Math Phys., To appear]. Here, the questions of global regularity vs. finite-time breakdown for the 2D Restricted Euler-Poisson solutions are classified in terms of precise explicit

Hiroki Horiuchi, Hiroaki Terao

Let $Δ$ be a finite set of nonzero linear forms in several variables with coefficients in a field $\mathbf K$ of characteristic zero. Consider the $\mathbf K$-algebra $R(Δ)$ of rational functions on V which are regular outside $\bigcup_{α\inΔ} \kerα$. Then the ring $R(Δ)$ is naturally doubly filtered by the degrees of denominators and of numerators. In this

B. Feigin, M. Jimbo, T. Miwa

We study a vertex operator algebra (VOA) V related to the M(3,p) Virasoro minimal series. This VOA reduces in the simplest case p=4 to the level two integrable vacuum module of $\hat{sl}_2$. On V there is an action of a commutative current a(z), which is an analog of the current e(z) of $\hat{sl}_2$. Our main concern is the subspace W generated by this actio

Kentaro Hori, Anton Kapustin

We provide a world-sheet description of Neveu-Schwarz five-branes wrapped on a complex projective space. It is an orbifold of the product of an N=2 minimal model and the IR fixed point of a certain linear sigma model. We show how the naked singularity in the supergravity description is resolved by the world-sheet CFT. Applying mirror symmetry, we show that t

Ashok Das, J. Maharana, A. Melikyan

The monodromy matrix, ${\hat{\cal M}}$, is constructed for two dimensional tree level string effective action. The pole structure of ${\hat{\cal M}}$ is derived using its factorizability property. It is found that the monodromy matrix transforms non-trivially under the non-compact T-duality group, which leaves the effective action invariant and this can be u

Jan Louis

We discuss some issues related to spontaneous N=2-> N=1 supersymmetry breaking. In particular, we state a set of geometrical conditions which are necessary that such a breaking occurs. Furthermore, we discuss the low energy N=1 effective Lagrangian and show that it satisfies non-trivial consistency conditions which can also be viewed as conditions on the geo

Lay Nam Chang, Djordje Minic, Naotoshi Okamura, Tatsu Takeuchi

We determine the energy eigenvalues and eigenfunctions of the harmonic oscillator where the coordinates and momenta are assumed to obey the modified commutation relations [x_i,p_j]=i hbar[(1+ beta p^2) delta_{ij} + beta' p_i p_j]. These commutation relations are motivated by the fact they lead to the minimal length uncertainty relations which appear in p

R. Vogt

We discuss a program for systematic studies of heavy quark production in $pp$, $pA$ and $AA$ interactions. The $Q \bar Q$ production cross sections themselves cannot be accurately predicted to better than 50% at RHIC. For studies of deviations in $Q \bar Q$ production such as those by nuclear shadowing and heavy quark energy loss, the $pp$ cross section thus

M. Boglione, M. R. Pennington

Starting with just one bare seed for each member of a scalar nonet, we investigate when it is possible to generate more than one hadronic state for each set of quantum numbers. In the framework of a simple model, we find that in the I=1 sector it is possible to generate two physical states with the right features to be identified with the a_0(980) and the a_

C. D. Froggatt, J. E. Dubicki

We investigate the possibility of incorporating a chiral fourth generation into a GUT model. We find that in order to do so, precision fits to electroweak observables demand the introduction of light (< M_Z) supersymmetric particles. This also enables us to provide decay channels to the fourth-generation quarks. Perturbative consistency sets an upper bound o

J. -M. Chung, B. K. Chung

As a generalization of a previous work [Phys. Rev. D. {\bf 59}, 105014 (1999)], we compute analytically a class of three-loop vacuum diagrams with two {\em arbitrarily} different mass scales. We use a decomposition algorithm in which the integrand of the final integral for the third momentum vector, say, $k$, becomes independent of the angles of $k$-vector i

Paramita Adhya, D. Rai Chaudhuri

Small Recent theories have proposed a variety of massive particles, like the moduli, whose abundance or decay endangers standard cosmological results. To dilute them, thermal inflation has been proposed, with its own massive scalar flaton field which goes on decaying in the era of Mev-scale temperatures. In this paper, the effect of late-time entropy product

D. Cavalli, A. Djouadi, K. Jakobs, A. Nikitenko

Report of the Higgs working group for the Workshop `Physics at TeV Colliders&#39;, Les Houches, France, 21 May - 1 June 2001. It contains 7 separate sections: A. Theoretical Developments B. Higgs Searches at the Tevatron C. Experimental Observation of an invisible Higgs Boson at LHC D. Search for the Standard Model Higgs Boson using Vector Boson Fusion at th

P. N. Burrows, J. R. Patterson

We report on Discussion Question 4, in Sub-group 1 (`TeV-class&#39;) of the Snowmass Working Group E3: `Experimental Approaches: Linear Colliders&#39;, which addresses the energy expandability of a linear collider. We first synthesize discussions of the energy reach of the hardware of the 500 GeV designs for TESLA and NLC/JLC. Next, we review plans for incre

S. Dain, O. M. Moreschi

The Goldberg-Sachs theorem has been very useful in constructing algebraically special exact solutions of Einstein vacuum equation. Most of the physical meaningful vacuum exact solutions are algebraically special. We show that the Goldberg-Sachs theorem is not true in linearized gravity. This is a remarkable result, which gives light on the understanding of t

Nguyen Suan Han, Nguyen Nhu Xuan

In the framework of functional integration the non-leading terms to leading eikonal behavior of the Planckian-energy scattering amplitude are calculated by the straight-line path approximation. We show that the allowance for the first-order correction terms leads to the appearance of retardation effect. The singular character of the correction terms at short

John Tromp, Paul Vitanyi

We present the first explicit, and currently simplest, randomized algorithm for 2-process wait-free test-and-set. It is implemented with two 4-valued single writer single reader atomic variables. A test-and-set takes at most 11 expected elementary steps, while a reset takes exactly 1 elementary step. Based on a finite-state analysis, the proofs of correctnes

R. Capovilla, J. Guven, J. A. Santiago

Consider a lipid membrane with a free exposed edge. The energy describing this membrane is quadratic in the extrinsic curvature of its geometry; that describing the edge is proportional to its length. In this note we determine the boundary conditions satisfied by the equilibria of the membrane on this edge, exploiting variational principles. The derivation i

M. Iavarone, G. Karapetrov, A. E. Koshelev, W. K. Kwok

The study of the anisotropic superconductor MgB2 using a combination of scanning tunneling microscopy and spectroscopy reveals two distinct energy gaps at Delta1=2.3 meV and Delta2=7.1 meV. Different spectral weights of the partial superconducting density of states (PDOS) are a reflection of different tunneling directions in this multi-band system. Our exper

Virgile Viasnoff, Francois Lequeux

We report the modifications of the microscopic dynamics of a colloidal glass submitted to shear. We use multispeckle diffusing wave spectroscopy to monitor the evolution of the spontaneous slow relaxation processes after the sample have been submitted to various straining. We show that high shear rejuvenates the system and accelerates its dynamics whereas mo

K. F. Laneri, J. Desimoni, G. J. Zarragoicoechea, A. Fernandez-Guillermet

This paper presents an experimental and theoretical study of the distribution of carbon atoms in the octahedral interstitial sites of the face-centered cubic (fcc) phase of the iron-carbon system. The experimental part of the work consists of Mossbauer measurements in Fe-C alloys with up to about 12 atomic percent C, which are interpreted in terms of two alt

Xin Wan, Kun Yang, R. N. Bhatt

We study the thermodynamics of one-dimensional quantum spin-1/2 Heisenberg ferromagnetic system with random antiferromagnetic impurity bonds. In the dilute impurity limit, we generalize the modified spin-wave theory for random spin chains, where local chemical potentials for spin-waves in ferromagnetic spin segments are introduced to ensure zero magnetizatio

R. Vaglio, M. G. Maglione, R. Di Capua

Thin films of the recently discovered magnesium diboride (MgB2) intermetalic superconducting compound have been grown using a magnetron sputtering deposition technique followed by in-situ annealing at 830 C. High quality films were obtained on both sapphire and MgO substrates. The best films showed maximum Tc = 35 K (onset), a transition width of 0.5 K, a re

S. De Franceschi, R. Hanson, W. G. van der Wiel, J. M. Elzerman

We study the non-equilibrium regime of the Kondo effect in a quantum dot laterally coupled to a narrow wire. We observe a split Kondo resonance when a finite bias voltage is imposed across the wire. The splitting is attributed to the creation of a double-step Fermi distribution function in the wire. Kondo correlations are strongly suppressed when the voltage

M. Liebendoerfer, O. E. B. Messer, A. Mezzacappa, W. R. Hix

Based on general relativistic three-flavor Boltzmann neutrino transport, we compare simulations of the postbounce evolution for five different stellar progenitors with 13 and 20 solar masses (Nomoto & Hashimoto &#39;88), and 15, 25, and 40 solar masses (Woosley & Weaver &#39;95).

M. P. Hobson, S. L. Bridle, O. Lahav

A method is presented for performing joint analyses of cosmological datasets, in which the weight assigned to each dataset is determined directly by it own statistical properties. The weights are considered in a Bayesian context as a set of hyperparameters, which are then marginalised over in order to recover the posterior distribution as a function only of

C. M. Dutra, E. Bica

In this study 21 catalogues of dust clouds in the Galaxy were cross-identified by taking into account available properties such as position, angular dimensions, opacity class and velocity. An initial list of $\approx$6500 entries was condensed into a cross-identified all-sky catalogue containing 5004 dust clouds. In particular, the transition zone between hi

T. P. Snow, D. E. Welty, J. Thorburn, L. M. Hobbs

As part of an extensive survey of diffuse interstellar bands (DIBs), we have obtained optical spectra of the moderately reddened B5V star HD 62542, which is known to have an unusual UV extinction curve of the type usually identified with dark clouds. The typically strongest of the commonly catalogued DIBs covered by the spectra -- those at 5780, 5797, 6270,