December 2001 arXiv papers — page 16

Taichi Kato, Daisaku Nogami, Hajime Baba

V651 Mon is the binary central star of the bipolar planetary nebula NGC 2346. The star showed the second-ever deep fading in 1996-1997, which was presumably caused by obscuration by a dust cloud in the planetary nebula, as was proposed to explain the 1981-1985 event. The entire duration of the 1996-1997 event was \~400 d, remarkably shorter than the 1981-198

Taichi Kato

U Sco is a recurrent nova which showed recorded outbursts in 1863, 1906, 1936, 1979, 1987, and most recently in 1999. The eclipsing nature of the object was discovered after the 1987 outburst. We examined our time-series photographic observations obtained during on 1987 May 20, which fortuitously covered the primary minimum (depth 0.8 mag). This postive dete

Jose K. Ishitsuka, Hiroshi Imai, Toshihiro Omodaka, Munetaka Ueno

We monitored water-vapor masers around the semi-regular variable star R Crateris with the Japanese VLBI Network (J-Net) at the 22 GHz band during four epochs with intervals of one month. The relative proper motions and Doppler-velocity drifts of twelve maser features were measured. Most of them existed for longer than 80 days. The 3-D kinematics of the featu

Warrick A. Lawson, Lisa A. Crause, Eric E. Mamajek, Eric D. Feigelson

A limited-area survey of the eta Chamaeleontis cluster has identified 2 new late-type members. The more significant of these is ECHA J0843.3-7905 (= IRAS F08450-7854), a slowly-rotating (P = 12 d) M2 classical T Tauri (CTT) star with a spectrum dominated by Balmer emission. At a distance of 97 pc and cluster age of approx 9 Myr, the star is a nearby rare exa

Eric J. Korpela, Paul Demorest, Eric Heien, Carl Heiles

SETI@home observes a 2.5 MHz bandwidth centered on 1420 MHz near the 21-cm line using a short line feed at Arecibo which provides a 6' beam. This feed sits on Carriage House 1. During normal astronomical observations with the new Gregorian dome the feed scans across the sky at twice the sidereal rate. We are using the SETI@home receiver to obtain about 4

Masatoshi Imanishi

We report on 3--4 $μ$m slit spectroscopy of 13 Seyfert 2 nuclei. The 3.3 $μ$m polycyclic aromatic hydrocarbon (PAH) emission is used to estimate the magnitudes of compact ($<$ a few 100 pc) nuclear starbursts and to resolve the controversy over their energetic importance in Seyfert 2 nuclei. For three selected Seyfert 2 nuclei that have been well studied in

Joseph Silk

I describe some of the current challenges in galaxy formation theory with applications to formation of disks and of spheroids. Forthcoming deep surveys of galaxies with Keck and VLT will provide high quality spectra of $\sim 10^5$ galaxies that will probe stellar populations and star formation rates at redshift unity. This will help refine our phenomenologic

D. N. Sheng, Ziqiang Wang, B. Friedman

We study the effects of disorder on the quantum Hall stripe phases in half-filled high Landau levels using exact numerical diagonalization. We show that, in the presence of weak disorder, a compressible, striped charge density wave, becomes the true ground state. The projected electron density profile resembles that of a smectic liquid. With increasing disor

Carl H. Albright, S. Geer

Within the framework of an SO(10) GUT model that can accommodate both the LMA and LOW solar neutrino mixing solutions by appropriate choice of the right-handed Majorana matrix elements, we present explicit predictions for the neutrino oscillation parameters Δm^2_{21}, \sin^2 2θ_{12}, \sin^2 2θ_{23}, \sin^2 2θ_{13}, and δ_{CP}. Given the observed near maximal

Jonathan Oppenheim, Michal Horodecki, Pawel Horodecki, Ryszard Horodecki

We consider the amount of work which can be extracted from a heat bath using a bipartite state shared by two parties. In general it is less then the amount of work extractable when one party is in possession of the entire state. We derive bounds for this &#34;work deficit&#34; and calculate it explicitly for a number of different cases. For pure states the w

Steven B. Giddings, Aleksey Nudelman

We provide examples of gravitational collapse and black hole formation in AdS, either from collapsing matter shells or in analogy to the Oppenheimer-Sneider solution. We then investigate boundary properties of the corresponding states. In particular, we describe the boundary two-point function corresponding to a shell outside its horizon; if the shell is qua

Adi Shamir, Boaz Tsaban

A major problem in using iterative number generators of the form x_i=f(x_{i-1}) is that they can enter unexpectedly short cycles. This is hard to analyze when the generator is designed, hard to detect in real time when the generator is used, and can have devastating cryptanalytic implications. In this paper we define a measure of security, called_sequence_di

O. Teodorescu, A. K. Dutt-Mazumder, C. Gale

We investigate the modification of meson spectral densities in dense nuclear matter at zero temperature. These effects are studied in a fully relativistic mean field model which goes beyond the linear density approximation and also includes baryon resonances. In particular, the role of N*(1520) and N*(1720) on the rho meson spectral density is highlighted. E

J. N. Fuchs, D. M. Gangardt, F. Laloe

We consider an ultracold gas of (non-condensed) bosons or fermions with two internal states, and study the effect of a gradient of the transition frequency between these states. When a $π/2$ RF pulse is applied to the sample, exchange effects during collisions transfer the atoms into internal states which depend on the direction of their velocity. This resul

Achod Aradian, Elie Raphael, Pierre-Gilles de Gennes

We present a short review of recent theoretical descriptions of flows occuring at the surface of granular piles, and focus mainly on two models: the phenomenological ``BCRE&#39;&#39; model and the hydrodynamic model, based on Saint-Venant equations. Both models distinguish a ``static phase&#39;&#39; and a ``rolling&#39;&#39; phase inside the granular packing

S. Prem Kumar, Jan Troost

We show how the elliptic Calogero-Moser integrable systems arise from a symplectic quotient construction, generalising the construction for A_{N-1} by Gorsky and Nekrasov to other algebras. This clarifies the role of (twisted) affine Kac-Moody algebras in elliptic Calogero-Moser systems and allows for a natural geometric construction of Lax operators for the

J. Barriga, E. Gaztanaga

This paper presents a comparison of the predictions for the 2 and 3-point correlation functions of density fluctuations, xi_2 and xi_3, in gravitational perturbation theory (PT) against large Cold Dark Matter (CDM) simulations. This comparison is made possible for the first time on large weakly non-linear scales (>10 Mpc/h) thanks to the development of a new

Christophe Texier

We consider the Friedel sum rule in the context of the scattering theory for the Schrödinger operator $-\Dc_x^2+V(x)$ on graphs made of one-dimensional wires connected to external leads. We generalize the Smith formula for graphs. We give several examples of graphs where the state counting method given by the Friedel sum rule is not working. The reason for t

A. B. Matsko, I. Novikova, G. R. Welch, D. Budker

When linearly polarized light propagates through a medium in which elliptically polarized light would undergo self-rotation, squeezed vacuum can appear in the orthogonal polarization. A simple relationship between self-rotation and the degree of vacuum squeezing is developed. Taking into account absorption, we find the optimum conditions for squeezing in any

F. Gulminelli, Ph. Chomaz

We investigate the relation between various statistical ensembles of finite systems. If ensembles differ at the level of fluctuations of the order parameter, we show that the equations of states can present major differences. A sufficient condition for this inequivalence to survive at the thermodynamical limit is worked out. If energy consists in a kinetic a

Jin-Ho Cho, Phillial Oh

An exact solution, in which a D2-brane and an anti-D2-brane are connected by an elliptically tubular D2-brane, is obtained without any junction condition. The solution is shown to preserve one quarter of the supersymmetries of the type-IIA Minkowski vacuum. We show that the configuration cannot be obtained by &#34;blowing-up&#34; from some inhomogeneously D0

D. Bar

We show, using quantum field theory, that performing a large number of identical repetitions of the same measurement does not only preserve the initial state of the wave function (the Zeno effect), but also produces additional physical effects. We first demonstrate that a Zeno type effect can emerges also in the framework of quantum field theory, that is, as

P. Castelo Ferreira, I. I. Kogan, R. J. Szabo

We continue the development of the topological membrane approach to open and unoriented string theories. We study orbifolds of topologically massive gauge theory defined on the geometry $[0,1]\timesΣ$, where $Σ$ is a generic compact Riemann surface. The orbifold operations are constructed by gauging the discrete symmetries of the bulk three-dimensional field

A. V. Efremov, K. Goeke, P. Schweitzer

Predictions are made for azimuthal asymmetries in pion and kaon production from SIDIS off a longitudinally polarized deuterium target for HERMES kinematics, based on information on the &#39;Collins fragmentation function&#39; from DELPHI data and on predictions for the transversity distribution function from non-perturbative calculations in the chiral quark-

Shay I. Heizler, David A. Kessler, Herbert Levine

We study Mode I fracture in a viscoelastic lattice model with a nonlinear force law, with a focus on the velocity and linear stability of the steady-state propagating solution. This study is a continuation both of the study of the piece-wise linear model in Mode I, and the study of more general nonlinear force laws in Mode III fracture. At small driving, the

Pierre Gaspard, Henk van Beijeren

Dynamical instability is studied in a deterministic dynamical system of Hamiltonian type composed of a tracer particle in a fluid of many particles. The tracer and fluid particles are hard balls (disks, in two dimensions, or spheres, in three dimensions) undergoing elastic collisions. The dynamical instability is characterized by the spectrum of Lyapunov exp

Peter Van

Weakly nonlocal thermodynamic theories are critically revisited. A relocalized, irreversible thermodynamic theory of nonlocal phenomena is given, based on a modified form of the entropy current and new kind of internal variables, the so called current multipliers. The treatment is restricted to deal with nonlocality connected to dynamic thermodynamic variabl

P. Valageas, R. Schaeffer, J. Silk

We investigate the behaviour of cosmological baryons at low redshifts $z<5$ after reionization through analytic means. In particular, we study the density-temperature phase-diagram which describes the history of the gas. We show how the location of the matter in this $(ρ,T)$ diagram expresses the various constraints implied by usual hierarchical scenarios. T

S. Cebrian, N. Coron, G. Dambier, E. Garcia

The ROSEBUD experiment for Direct Dark Matter detection settled in 1999 in the Canfranc Underground Laboratory. The first phase of the experiment was dedicated to the understanding and reduction of the radioactive background following successive removals of the radioimpure materials. Sapphire (25g, 50g) and germanium (67g) absorbers were used. Thresholds res

Mayeul Arminjon

An optimization program is used to re-adjust the initial conditions, in order to reproduce as closely as possible the predictions of a complete ephemeris by using simplified equations of motion in the numerical integration. The adjustment of the initial conditions is illustrated in the transition from the DE406 complete long-range ephemeris to a Newtonian mo

Qiuping A. Wang

The factorization problem of $q$-exponential distribution within nonextensive statistical mechanics is discussed on the basis of Abe&#39;s general pseudoadditivity for equilibrium systems. it is argued that the factorization of compound probability into product of the probabilities of subsystems is nothing but the consequence of existence of thermodynamic eq

Yoshiaki Himemoto, Takahiro Tanaka, Misao Sasaki

Based on the recently proposed scenario of inflation driven by a bulk scalar field in the braneworld of the Randall-Sundrum (RS) type, we investigate the dynamics of a bulk scalar field on the inflating braneworld. We derive the late time behavior of the bulk scalar field by analyzing the property of the retarded Green function. We find that the late time be

C. Q. Geng, C. W. Hwang

We analyze $K_L$ lepton pair decays of $K_L \to l^+ł^-γ$ and $K_L \to l^+l^-l&#39;^+l&#39;^-$ $(l, l&#39;=e, μ)$ within the framework of the light-front QCD approach (LFQA). With the $K_L \to γ^* γ^*$ form factors evaluated in a model with the LFQA, we calculate the decay branching ratios and find out that our results are all consistent with the experimental

Gi-Chol Cho, Naoyuki Haba, Junji Hisano

We study the possibility that the lepton-flavor changing process can induce the suitable magnitude of the muon anomalous magnetic moment (g_μ-2) in the decoupling solution to the flavor problem in the minimal supersymmetric standard model. Our analyses introduce the flavor mixings of left- and right-handed stau and smuon phenomenologically. It is found that

Adam S. Sikora

The cut number of a manifold M, c(M), is the largest number of disjoint two-sided hypersurfaces in M which do not separate M. Equivalently, it is the largest rank of a free group being an epimorphic image of pi_1(M). We investigate the relations between the cut number and the first Betti number, b_1(M), of 3-manifolds M. We prove that the cut number of a ``g

Masaki Kanada, Yukio Yasui, Yasuyuki Kondo, Satoshi Iikubo

Intensity distribution of the neutron magnetic scattering has been taken in the reciprocal space of a single crystal of the &#34;spin ice&#34; system Ho2Ti2O7 at the elastic energy position in the temperature (T) region between 0.4 K and 50 K. The short range magnetic correlation becomes appreciable with decreasing T at around 30 K. The freezing of the momen

H. C. Rosu, L. Madueno, J. Socorro

We use a particular fractional generalization of the ordinary differential equations that we apply to the Riccati equation of constant coefficients. By this means the latter is transformed into a modified Riccati equation with the free term expressed as a power of the independent variable which is of the same order as the order of the applied fractional deri

Laurent Bartholdi

This paper gives lower bounds on the spectral radius of vertex-transitive graphs, based on the number of ``prime cycles'' at a vertex. The bounds are obtained by constructing circuits in the graph that resemble ``cactus trees'', and enumerating them. Counting these circuits gives a coefficient-wise underestimation of the Green function of the graph, and henc

Lev B. Levitin, Tommaso Toffoli, Zac D. Walton

We consider a fixed quantum measurement performed over $n$ identical copies of quantum states. Using a rigorous notion of distinguishability We consider a fixed quantum measurement performed over $n$ identical copies of quantum states. Using a rigorous notion of distinguishability based on Shannon&#39;s 12th theorem, we show that in the case of a single qubi

Artur K. Ekert, Carolina Moura Alves, Daniel K. L. Oi, Michal Horodecki

We present a simple device based on the controlled-SWAP gate that performs quantum state tomography. It can also be used to determine maximum and minimum eigenvalues, expectation values of arbitrary observables, purity estimation as well as characterizing quantum channels. The advantage of this scheme is that the architecture is fixed and the task performed

J. Guerrero, V. I. Manko, G. Marmo, A. Simoni

In this paper we present a new procedure to obtain unitary and irreducible representations of Lie groups starting from the cotangent bundle of the group (the cotangent group). We discuss some applications of the construction in quantum-optics problems.

I. Pitowsky

We consider the set of all matrices of the form $p_{ij}=tr[W(E_{i}\otimes F_{j})]$ where $E_{i}$, $F_{j}$ are projections on a Hilbert space $H$, and $W$ is some state on $H\otimes H$. We derive the basic properties of this set, compare it with the classical range of probability, and note how its properties may be related to geometric measures of entanglemen

Benjamin Rahn, Andrew C. Doherty, Hideo Mabuchi

We derive the effective channel for a logical qubit protected by an arbitrary quantum error-correcting code, and derive the map between channels induced by concatenation. For certain codes in the presence of single-bit Pauli errors, we calculate the exact threshold error probability for perfect fidelity in the infinite concatenation limit. We then use the co

Bruce Rosenblum, Fred Kuttner

A goal of most interpretations of quantum mechanics is to avoid the apparent intrusion of the observer into the measurement process. Such intrusion is usually seen to arise because observation somehow selects a single actuality from among the many possibilities represented by the wavefunction. The issue is typically treated in terms of the mathematical formu

Andrei Derevianko, Sergey Porsev

In light of new data on neutron distributions from experiments with antiprotonic atoms [ Trzcinska {\it et al.}, Phys. Rev. Lett. 87, 082501 (2001)], we reexamine the role of nuclear-structure uncertainties in the interpretation of measurements of parity violation in atoms using chains of isotopes of the same element. With these new nuclear data, we find an

Adrian Faigon

Mechanics can be founded in a principle stating the uncertainty in the position of an observable particle delta-q as a function of its motion relative to the observer, expressed in a trajectory representation . From this principle, p.delta-q=const., being p the q-conjugated momentum, mechanical laws are derived and the meaning of the Lagrangian and Hamiltoni

A. G. Shkvarunets, R. B. Fiorito, P. G. O&#39;Shea

Optical transition radiation interferometry (OTRI) has been shown to be a very useful technique to measure the divergence of electron beams with energies in the range of 15-100 MeV. However, application of this method to low energy or very high quality beams is limited by scattering in the front foil of the interferometer. To overcome this limitation we prop

A. Suraci, T. Bager, Ch. Balle, E. Blanco

CERN is now setting up String 2, a full-size prototype of a regular cell of the LHC arc. It is composed of two quadrupole, six dipole magnets, and a separate cryogenic distribution line (QRL) for the supply and recovery of the cryogen. An electrical feed box (DFB), with up to 38 High Temperature Superconducting (HTS) leads, powers the magnets. About 700 sens

Jason R. Cooke, Gerald A. Miller

The objective of this paper is to investigate how the breaking of manifest rotational invariance in light-front dynamics affects the binding energy and the form factors of the deuteron. To do this, we derive new light-front nucleon-nucleon one- and two-meson-exchange potentials, and use the potentials to solve for the deuteron wave function and binding energ

W. M. Alberico, G. Garbarino

In this review we discuss the present status of strange nuclear physics, with special attention to the weak decay of Lambda hypernuclei. The models proposed for the evaluation of the Lambda decay widths are summarized and their results are compared with the data. Despite the recent intensive investigations, the main open problem remains a sound theoretical i

B. Liu, V. Greco, V. Baran, M. Colonna

We try to single out some qualitative new effects of the coupling to the $δ$-isovector-scalar meson introduced in a minimal way in a phenomenological hadronic field theory. Results for the equation of state ($EOS$) and the phase diagram of asymmetric nuclear matter ($ANM$) are discussed. We stress the consistency of the $δ$-coupling introduction in a relativ

E. Oset, L. Roca, M. J. Vicente Vacas, J. C. Nacher

In this talk we report on two physical processes, the photoproduction of $ρ$ mesons in nuclei and the $π^0 π^0$ photoproduction in nuclei at low energies. In the first case the aim is to observe experimentally the theoretically predicted changes on the $ρ$ properties in the nuclear medium. In the second case one wishes to investigate the modifications of the

Gentaro Watanabe, Katsuhiko Sato, Kenji Yasuoka, Toshikazu Ebisuzaki

Structure of cold dense stellar matter at subnuclear densities is investigated with quantum molecular dynamics (QMD). We succeeded in showing that the phases with slab-like and rod-like nuclei etc. can be formed dynamically without any assumptions on the nuclear shape. Our result suggests the existence of these kinds of phases in neutron star crusts.

Kristof Kaly-Kullai

Waves in excitable media can be treated by a simple geometric theory. The propagation velocity is assumed known and evolution of wave fronts is determined by elementary physical principles (Fermat&#39;s principle, Huygens&#39; principle). Based on this geometric theory a fast computational method is developed. By this method the distorting effect of the spat

Habib Ammari, Hyeonbae Kang

We derive high-order terms in the asymptotic expansions of the steady-state voltage potentials in the presence of a finite number of diametrically small inhomogeneities with conductivities different from the background conductivity. Our derivation is rigorous, and based on layer potential techniques. The asymptotic expansions in this paper are valid for inho

Victor G. Kac, Alexei Rudakov

In this paper complexes of generalized Verma modules over the infinite-dimensional exceptional Lie superalgebras $E (3,8)$ and $E(5,10)$ are constructed and studied.

A. M. Perelomov

An integral representation for matrix Airy function is presented

Fritz Gesztesy, Lev A. Sakhnovich

We construct a class of matrix-valued Schrödinger operators with prescribed finite-band spectra of maximum spectral multiplicity. The corresponding matrix potentials are shown to be stationary solutions of the KdV hierarchy. The methods employed in this paper rely on matrix-valued Herglotz functions, Weyl--Titchmarsh theory, pencils of matrices, and basic in

R. M. Green

We introduce the notion of 321-avoiding permutations in the affine Weyl group $W$ of type $A_{n-1}$ by considering the group as a George group (in the sense of Eriksson and Eriksson). This enables us to generalize a result of Billey, Jockusch and Stanley to show that the 321-avoiding permutations in $W$ coincide with the set of fully commutative elements; in

Martin Lorenz

Let $G$ be a finitely generated abelian-by-finite group and $k$ a field of characteristic $p\ge 0$. The Euler class $[k_G]$ of $G$ over $k$ is the class of the trivial $kG$-module in the Grothendieck group $G_0(kG)$. We show that $[k_G]$ has finite order if and only if every $p$-regular element of $G$ has infinite centralizer in $G$. We also give a lower bou

Peter Constantin

The Navier-Stokes equations and their various approximations can be described in terms of near identity maps, that are diffusive particle path transformations of physical space. The active velocity is obtained from the diffusive path transformation and a virtual velocity using the Weber formula. The active vorticity is obtained from the diffusive path transf

B. Feigin, M. Jimbo, T. Miwa, E. Mukhin

For each pair of positive integers (k,r) such that k+1,r-1 are coprime, we introduce an ideal $I^{(k,r)}_n$ of the ring of symmetric polynomials. The ideal $I^{(k,r)}_n$ has a basis consisting of Jack polynomials with parameter $β=-(r-1)/(k+1)$, and admits an action of a family of differential operators of Dunkl type including the positive half of the Viraso

Salih Celik, Emanullah Hizel

The $h$-deformation of functions on the Grassmann matrix group $Gr(2)$ is presented via a contraction of $Gr_q(2)$. As an interesting point, we have seen that, in the case of the $h$-deformation, both R-matrices of $GL_h(2)$ and $Gr_h(2)$ are the same.

Salih Celik, Sultan A. Celik, Metin Arik

We give a two-parameter quantum deformation of the exterior plane and its differential calculus without the use of any R-matrix and relate it to the differential calculus with the R-matrix. We prove that there are two types of solutions of the Yang-Baxter equation whose symmetry group is $GL_{p,q}(2)$. We also give a two-parameter deformation of the fermioni

Salih Celik

The differential calculus on the quantum supergroup GL$_q(1| 1)$ was introduced by Schmidke {\it et al}. (1990 {\it Z. Phys. C} {\bf 48} 249). We construct a differential calculus on the quantum supergroup GL$_q(1| 1)$ in a different way and we obtain its quantum superalgebra. The main structures are derived without an R-matrix. It is seen that the found res

Sultan A. Celik, Salih Celik

Hopf algebra structure on the differential algebra of the extended $q$-plane is defined. An algebra of forms which is obtained from the generators of the extended $q$-plane is introduced and its Hopf algebra structure is given.

Salih Celik

We construct a two-parameter covariant differential calculus on the quantum $h$-exterior plane. We also give a deformation of the two-dimensional fermionic phase space.

Salih Celik

We construct a right-invariant differential calculus on the quantum supergroup GL$_h(1| 1)$ and obtain the $h$-deformed superalgebra of GL$_h(1| 1)$.

Salih Celik

In this Letter, we introduce the Hopf algebra structure of the quantum quaternionic group GL(1,H$_q)$ and discuss the isomorphism between the quantum symplectic group SP$_q(1)$ and the quantum unitary group SU$_q(2)$.

G. Bergdolt

The group algebra of the permutation group is spanned by a set of elements called projectors. The coordinates of permutations expanded in projectors are matrix elements of irreducible representations. The projectors of the permutation group are a product of a Young symmetriser and a Young antisymmetriser. They form non-orthogonal bases of right and left modu

Alain Berthomieu

The spectrum of the Laplace-Dolbeault operator for any line bundle with parallel curvature on a flat complex torus is computed. The Ray-Singer analytic torsion is then deduced, generalizing thus Bost&#39;s result for ample line bundles and Ray-Singer&#39;s ones for flat bundles, of which we a geometric interpretation is given.

Vicente Cortes

This is a survey of recent contributions to the area of special Kaehler geometry. It is based on lectures given at the 21st Winter School on Geometry and Physics held in Srni in January 2001.

Moulay-Tahar Benameur, Herve Oyono-Oyono

In the present paper, we give a proof of the gap-labelling conjecture for quasi-crystals. The main tools are the measured index theorem for laminations and a naturality of the longitudinal Chern character.

Jacek Brodzki, Roger Plymen

We describe a geometric counterpart of the Baum-Connes map for the p-adic group GL(n).

Enrico Carlini, Jaydeep Chipalkatti

We reconsider the classical problem of representing a finite number of forms of degree d in n+1 variables as sums of powers of linear forms. We define a geometric construct called a `grove&#39;, which, in a number of cases allows us to determine the dimension of the space of forms which can be so represented. We also present two new `exceptional&#39; example

Laurent Bartholdi

I compute the structure of the restricted 2-algebra associated to a group first described by Andrew Brunner, Said Sidki and Ana Cristina Vieira, acting on the binary rooted tree. I show that its width is unbounded, growing logarithmically, and obeys a simple rule. As a consequence, the dimension of the successive quotients of powers of the augmentation ideal

B. Feigin, M. Jimbo, S. Loktev, T. Miwa

Bosonic formulas for generating series of partitions with certain restrictions are obtained by solving a set of linear matrix q-difference equations. Some particular cases are related to combinatorial problems arising from solvable lattice models, representation theory and conformal field theory.

Angela Gibney, Sean Keel, Ian Morrison

In this paper we study the ample cone of the moduli space $\mgn$ of stable $n$-pointed curves of genus $g$. Our motivating conjecture is that a divisor on $\mgn$ is ample iff it has positive intersection with all 1-dimensional strata (the components of the locus of curves with at least $3g+n-2$ nodes). This translates into a simple conjectural description of

D. V. Gal&#39;tsov

We discuss the radiation reaction problem for an electric charge moving in flat space-time of arbitrary dimensions. It is shown that four is the unique dimension where a local differential equation exists accounting for the radiation reaction and admitting a consistent mass-renormalization (the Dirac-Lorentz equation). In odd dimensions the Huygens principle

P. Merlatti

I study the enhancon mechanism for fractional D-branes in conifold and orbifold backgrounds and show how it can resolve the ``repulson&#39;&#39; singularity of these geometries. In particular I show that the consistency of the excision process requires that the interior space be not empty.

Andrej Brzoska, Michael Thies

Within a variational calculation we investigate the role of baryons for the structure of dense matter in the Gross-Neveu model. We construct a trial ground state at finite baryon density which breaks translational invariance. Its scalar potential interpolates between widely spaced kinks and antikinks at low density and the value zero at infinite density. Its

D. M. Gitman, I. V. Tyutin

The way of finding all the constraints in the Hamiltonian formulation of singular (in particular, gauge) theories is called the Dirac procedure. The constraints are naturally classified according to the correspondig stages of this procedure. On the other hand, it is convenient to reorganize the constraints such that they are explicitly decomposed into the fi

L. Cantini, P. Menotti, D. Seminara

After briefly reviewing the hamiltonian approach to 2+1 dimensional gravity in absence of matter on closed universes, we consider 2+1 dimensional gravity coupled to point particles in an open universe. We show that the hamiltonian structure of the theory is the result of a conjecture put forward by Polyakov in a different context. A proof is given of such a

Takao Suyama

We discuss the condensation of charged tachyons in the heterotic theory on the Kaluza-Klein Melvin background. The arguments are based on duality relations which are expected to hold from the adiabatic argument. It is argued that in many cases the rank of the gauge group is not changed by the condensation, as opposed to naive expectations.

E. Sezgin, P. Sundell

We construct the minimal bosonic higher spin extension of the 7D AdS algebra SO(6,2), which we call hs(8*). The generators, which have spin s=1,3,5,..., are realized as monomials in Grassmann even spinor oscillators. Irreducibility, in the form of tracelessness, is achieved by modding out an infinite dimensional ideal containing the traces. In this a key rol

M. Cvetic, G. W. Gibbons, H. Lu, C. N. Pope

Seven-manifolds of G_2 holonomy provide a bridge between M-theory and string theory, via Kaluza-Klein reduction to Calabi-Yau six-manifolds. We find first-order equations for a new family of G_2 metrics D_7, with S^3\times S^3 principal orbits. These are related at weak string coupling to the resolved conifold, paralleling earlier examples B_7 that are relat

Z. Chacko, Markus A. Luty

We present a simple general framework for realistic models of supersymmetry breaking driven by anomaly mediation. We consider a 5-dimensional &#34;brane universe&#34; where the visible and hidden sectors are localized on different branes, and the standard model gauge bosons propagate in the bulk. In this framework there can be charged scalar messengers that

E. Fischbach, A. W. Overhauser, B. Woodahl

We analyze the decays $ϕ\to K\bar{K}$ utilizing a formulation of transition rates which explicitly exhibits corrections to Fermi&#39;s Golden Rule. These corrections arise in systems in which the phase space and/or matrix element varies rapidly with energy, as happens in $ϕ\to K\bar{K}$, which is just above threshold. We show that the theoretical corrections

M. Battaglia, A. De Roeck, T. Rizzo

Direct production of Kaluza-Klein states in the TeV range is studied for the experimental environment at the multi-TeV $e^+e^-$ collider CLIC. The sensitivity of such data to model parameters is discussed for the Randall-Sundrum(RS) and TeV scale extra dimensional models.

Shinya Kanemura, C. -P. Yuan

In the Minimal Supersymmetric Standard Model (MSSM), the masses of the charged Higgs boson ($H^\pm$) and the CP-odd scalar ($A$) are related by $M_{H^+}^2=M_A^2+m_W^2$. Furthermore, because the coupling of $W^-$-$A$-$H^+$ is fixed by gauge interaction, the tree level production rate of $q \bar q&#39; \to W^{\pm \ast} \to A H^\pm$ depends only on one supersym

Todd D. Fugleberg

In dense quark matter, the response of the color superconducting gaps to a small variation, $δμ$, in the chemical potential of the strange quark was studied. The approximation of three massless flavors of quarks and a general ansatz for the color flavor structure of the gap matrix was used. The general pole structure of the quasi-particle propagator in this

O. Kiriyama

Chiral meson masses at the critical point is investigated using QCD in the improved ladder approximation. We calculate the effective potential at finite temperature $T$ and quark chemical potential $μ$ and find the critical point at $T \simeq 95$ MeV, $μ\simeq 290$ MeV. The chiral meson masses are determined from the second derivative of the effective potent

D. Bardin, L. Kalinovskaya, G. Nanava

We present a description of calculations of the electroweak amplitude for e+ e- --> f fbar process. The calculations are done within the OMS (on-mass-shell) renormalization scheme in two gauges: in Rxi, which allows an explicit control of gauge invariance by examining cancellation of gauge parameters and search for gauge-invariant subsets of diagrams, and in

A. Wichmann, D. Schuette, B. C. Metsch, V. Wethkamp

The glueball spectrum within the Hamiltonian formulation of lattice gauge theory (without fermions) is calculated for the gauge group SU(2) and for two spatial dimensions. The Hilbert space of gauge-invariant functions of the gauge field is generated by its parallel-transporters on closed paths along the links of the spatial lattice. The coupled cluster meth

James Geddes

In models of spacetime that are the product of a four-dimensional spacetime with an ``extra&#39;&#39; dimension, there is the possibility that the extra dimension will collapse to zero size, forming a singularity. We ask whether this collapse is likely to destroy the spacetime. We argue, by an appeal to the four-dimensional cosmic censorship conjecture, that

Daniel Krob, Jean Mairesse, Ioannis Michos

The {\em height} of a trace is the height of the corresponding heap of pieces in Viennot&#39;s representation, or equivalently the number of factors in its Cartier-Foata decomposition. Let $h(t)$ and $|t|$ stand respectively for the height and the length of a trace $t$. Roughly speaking, $|t|$ is the `sequential&#39; execution time and $h(t)$ is the `paralle

A. Korotkov, M. Bowman, H. J. McGuinness, D. Davidovic

We describe a method for creating atomic-scale electric contacts. A metal source is deposited on two insulating substrates separated by a 70 nm gap. Electric conductance across the gap is monitored, while protrusions from the bulk extend into the gap and reach corresponding protrusions on the other side of the gap. When the voltage across the gap is large, a

K. M. Lang, V. Madhavan, J. E. Hoffman, E. W. Hudson

Granular superconductivity occurs when microscopic superconducting grains are separated by non-superconducting regions through which they communicate by Josephson tunneling to establish the macroscopic superconducting state [1]. Although crystals of the cuprate high-Tc superconductors are not granular in a structural sense, theory indicates that at low hole

M. Lopez de Haro, J. A. del Rio, F. Vazquez

The light-scattering spectrum for a Maxwell fluid in a steady state due to the presence of an external temperature gradient is computed. In such a fluid heat conduction is assumed to be governed by the classical Fourier law. The calculation is carried out through the use of fluctuating hydrodynamics. The effect of the non-Newtonian character of the fluid in

C. P. Ewels, M. I. Heggie, P. R. Briddon

We present a new and general mechanism for inter-conversion of carbon structures via a catalytic exchange process, which operates under conditions of Frenkel pair generation. The mechanism typically lowers reaction barriers by a factor of four compared to equivilent uncatalysed reactions. We examine the relevance of this mechanism for fullerene growth, carbo