January 2005 arXiv papers

Heron Caldas, C. W. Morais, A. L. Mota

In this paper, we study phase transitions in asymmetrical fermion superfluids. In this scenario, the candidates to form pair are particles with mismatched masses and chemical potentials. We derive an expression for the critical temperature in terms of the gap and masses (or chemical potentials) when the constraint of equal Fermi surfaces $m_aμ_a = m_bμ_b$ is

E. Ya. Sherman, Ali Najmaie, J. E. Sipe

We show that a pure spin current can be injected in quantum wells by the absorption of linearly polarized infrared radiation, leading to transitions between subbands. The magnitude and the direction of the spin current depend on the Dresselhaus and Rashba spin-orbit coupling constants and light frequency and, therefore, can be manipulated by changing the lig

C. Z. Waters, S. E. Zepf

We present new ultraviolet photometry of the jet in M87 obtained from HST WFPC2 imaging. We combine these ultraviolet data with previously published photometry for the knots of the jet in radio, optical, and X-ray, and fit three theoretical synchrotron models to the full data set. The synchrotron models consistently overpredict the flux in the ultraviolet wh

Ralph Blumenhagen, Mirjam Cvetic, Paul Langacker, Gary Shiu

We provide a pedagogical introduction to a recently studied class of phenomenologically interesting string models, known as Intersecting D-Brane Models. The gauge fields of the Standard-Model are localized on D-branes wrapping certain compact cycles on an underlying geometry, whose intersections can give rise to chiral fermions. We address the basic issues a

Virginia V. Fernandez, Waldyr A. Rodrigues, Antonio M. Moya, Roldao da Rocha

Here (the last paper in a series of four) we end our presentation of the basics of a systematical approach to the differential geometry of a smooth manifold M (supporting a metric field g and a general connection del) which uses the geometric algebras of multivector and extensors (fields) developed in previous papers. The theory of the Riemann and Ricci fiel

Kentaro Nagamine, Renyue Cen, Lars Hernquist, Jeremiah P. Ostriker

Recent observations have revealed a population of red massive galaxies at high redshift which are challenging to explain in hierarchical galaxy formation models. We analyze this ``massive galaxy problem'' with two different types of hydrodynamic simulations -- Eulerian TVD and SPH -- of a concordance Lambda CDM universe. We consider two separate but

Eylee Jung, D. K. Park

The absorption and emission problems of the brane-localized and bulk scalars are examined when the spacetime is a $(4+n)$-dimensional Reissner-Nordström black hole. Making use of an appropriate analytic continuation, we compute the absorption and emission spectra in the full range of particle's energy. For the case of the brane-localized scalar the prese

Zvi Bern, Lance J. Dixon, David A. Kosower

We present examples of on-shell recurrence relations for determining rational functions appearing in one-loop QCD amplitudes. In particular, we give relations for one-loop QCD amplitudes with all legs of positive helicity, or with one leg of negative helicity and the rest of positive helicity. Our recursion relations are similar to the tree-level ones descri

Hisham Sati

In this note we show that the Chern-Simons and the one-loop terms in the M-theory action can be written in terms of new characters involving the M-theory four-form and the string classes. This sheds a new light on the topological structure behind M-theory and suggests the construction of a theory of `higher' characteristic classes.

A. M. Moya, V. V. Fernandez, W. A. Rodrigues

The objective of the present paper (the second in a series of four) is to give a theory of multivector and extensor fields on a smooth manifold M of arbitrary topology based on the powerful geometric algebra of multivectors and extensors. Our approach does not suffer the problems of earlier attempts which are restricted to vector manifolds. It is based on th

Emiliano Papa, Allan H. Macdonald

In this paper we introduce and study the correlation functions of a chiral one-dimensional electron model intended to qualitatively represent narrow Hall bars separated into left and right sections by a penetrable barrier. The model has two parameters representing respectively interactions between top and bottom edges of the Hall bar and interactions between

P. Benes, Amand Faessler, S. Kovalenko, F. Simkovic

We study possible contribution of the Majorana neutrino mass eigenstate $ν_h$ dominated by a sterile neutrino component to neutrinoless double beta ($0νββ$) decay. From the current experimental lower bound on the $0νββ$-decay half-life of $^{76}$Ge we derive stringent constraints on the $ν_h-ν_e$ mixing in a wide region of the values of $ν_h$ mass. We discus

L. Hozoi, S. Nishimoto, A. Yamasaki

We analyze the electronic structure of a mixed-valence ladder system. We find that structural anisotropy and complex electron correlations lead to on-rung charge localization and insulating character. Charge fluctuations within the rung of the ladder interact strongly to the lattice degrees of freedom, which gives rise to large pseudo Jahn--Teller effects. T

Boris E. Stern, Juri Poutanen

We suggest a method for statistical tests which does not suffer from a posteriori manipulations with tested samples (e.g. cuts optimization) and does not require a somewhat obscure procedure of the penalty estimate. The idea of the method is to hide the real sample (before it has been studied) among a large number of artificial samples, drawn from a random d

Stefan Antusch, Joern Kersten, Manfred Lindner, Michael Ratz

We systematically analyze quantum corrections in see-saw scenarios, including effects from above the see-saw scales. We derive approximate renormalization group equations for neutrino masses, lepton mixings and CP phases, yielding an analytic understanding and a simple estimate of the size of the effects. Even for hierarchical masses, they often exceed the p

A. Gehrmann--De Ridder, T. Gehrmann, E. W. N. Glover

The computation of exclusive QCD jet observables at higher orders requires a method for the subtraction of infrared singular configurations arising from multiple radiation of real partons. One commonly used method at next-to-leading order (NLO) is based on the antenna factorization of colour-ordered matrix elements, and uses antenna functions to subtract the

T. Kawahara

On the basis of the relativistic symmetry of Minkowski space, we derive a Lorentz invariant equation for a spread electron. This equation slightly differs from the Dirac equation and includes additional terms originating from the spread of an electron. Further, we calculate the anomalous magnetic moment based on these terms. These calculations do not include

Mei-Rong Li, Karyn Le Hur, Walter Hofstetter

We show that the Bose-Fermi Kondo model (BFKM), which may find applicability both to certain dissipative mesoscopic qubit devices and to heavy fermion systems described by the Kondo lattice model, can be mapped exactly onto the Caldeira-Leggett model. This mapping requires an ohmic bosonic bath and an Ising-type coupling between the latter and the impurity s

Prabodh Shukla

Coarsening and persistence of Ising spins on a ladder is examined under voter dynamics. The density of domain walls decreases algebraically with time as $t^-{1/2}$ for sequential as well as parallel dynamics. The persistence probability decreases as $t^{-θ_{s}}$ under sequential dynamics, and as $t^{-θ_{p}}$ under parallel dynamics where $θ_{p} = 2 θ_{s} \ap

M. Beneke, Y. Kiyo, K. Schuller

We obtain analytic expressions for the third-order corrections due to the strong interaction Coulomb potential to the S-wave Green function, energy levels and wave functions at the origin for arbitrary principal quantum number n. Together with the known non-Coulomb correction this results in the complete spectrum of S-states up to order alpha_s^5. The numeri

A. Brandenburg, L. Covi, K. Hamaguchi, L. Roszkowski

The axino and the gravitino are well-motivated candidates for the lightest supersymmetric particle (LSP) and also for cold dark matter in the Universe. Assuming that a charged slepton is the next-to-lightest supersymmetric particle (NLSP), we show how the NLSP decays can be used to probe the axino LSP scenario in hadronic axion models as well as the gravitin

Kinjal Banerjee, Ghanashyam Date

One of the qualitatively distinct and robust implication of Loop Quantum Gravity (LQG) is the underlying discrete structure. In the cosmological context elucidated by Loop Quantum Cosmology (LQC), this is manifested by the Hamiltonian constraint equation being a (partial) difference equation. One obtains an effective Hamiltonian framework by making the conti

J. Deng, N. Tominaga, P. A. Mazzali, K. Maeda

The net optical light curves and spectra of the supernova (SN) 2003dh are obtained from the published spectra of GRB 030329, covering about 6 days before SN maximum to about 60 days after. The bulk of the U-band flux is subtracted from the observed spectra using early-time afterglow templates, because strong line blanketing greatly depresses the UV and U-ban

Thierry Dauxois, Michel Peyrard, Stefano Ruffo

The Fermi-Pasta-Ulam (FPU) pioneering numerical experiment played a major role in the history of computer simulation because it introduced this concept for the first time. Moreover, it raised a puzzling question which was answered more than 10 years later. After an introduction to this problem, we briefly review its history and then suggest some simple numer

The Compass Collaboration, E. S. Ageev

We present a new measurement of the longitudinal spin asymmetry A_1^d and the spin-dependent structure function g_1^d of the deuteron in the range 1 GeV^2 < Q^2 < 100 GeV^2 and 0.004< x <0.7. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarised muon beam and a large polarised 6-LiD target. The results are in agreement with those

Louis Funar

Let $Σ$ be a compact surface. We prove that the set of surface cubications modulo flips, up to isotopy, is in one-to-one correspondence with $\Z/2\Z\oplus H_1(Σ,\Z/2\Z)$.

Alberto Diez-Tejedor, Alexander Feinstein

We consider hydrodynamics with non conserved number of particles and show that it can be modeled with effective fluid Lagrangians which explicitly depend on the velocity potentials. For such theories, the {}``shift symetry&#39;&#39; $ϕ\toϕ+$const. leading to the conserved number of fluid particles in conventional hydrodynamics is globaly broken and, as a res

Ruth Lawrence, Ofer Ron

We give a self-contained treatment of Le and Habiro&#39;s approach to the Jones function of a knot and Habiro&#39;s cyclotomic form of the Ohtsuki invariant for manifolds obtained by surgery around a knot. On the way we reproduce a state sum formula of Garoufalidis and Le for the colored Jones function of a knot. As a corollary, we obtain bounds on the growt

Ralf Meyer

Let G be a reductive group over a non-Archimedean local field. Then the canonical functor from the derived category of smooth tempered representations of G to the derived category of all smooth representations of G is fully faithful. Here we consider representations on bornological vector spaces. As a consequence, if V and W are two tempered irreducible repr

Tim Perutz

Users of Heegaard Floer homology may be reassured to know that it can be made to conform exactly to the standard analytic pattern of Lagrangian Floer homology. This follows from the following remark, which we prove using an argument of J. Varouchas: the natural singular Kähler form $\sym^n(ω)$ on the $n$th symmetric product of a Kähler curve $(Σ,ω)$ admits a

Jorge Bellorin, Tomas Ortin

We show how the Killing Spinor Identities (KSI) can be used to reduce the number of independent equations of motion that need to be checked explicitly to make sure that a supersymmetric configuration is a classical supergravity solution. We also show how the KSI can be used to compute BPS relations between masses and charges.

V. J. Bolós

The aim of this paper is to study foliations that remain invariant by parallel transports along the integral curves of vector fields of another foliations. According to this idea, we define a new concept of stability between foliations. A particular case of stability (called regular stability) is studied, giving a useful characterization in terms of the Riem

Matti Peltomaki, Ville Vuorinen, Mikko Alava, Martin Rost

The behavior of two interacting populations, ``hosts&#39;&#39;and ``parasites&#39;&#39;, is investigated on Cayley trees and scale-free networks. In the former case analytical and numerical arguments elucidate a phase diagram, whose most interesting feature is the absence of a tri-critical point as a function of the two independent spreading parameters. For

X. Barnabe-Theriault, A. Sedeki, V. Meden, K. Schoenhammer

We investigate transport of spinless fermions through a single site dot junction of M one-dimensional quantum wires. The semi-infinite wires are described by a tight-binding model. Each wire consists of two parts: the non-interacting leads and a region of finite extent in which the fermions interact via a nearest-neighbor interaction. The functional renormal

Md. Manirul Ali, A. S. Majumdar, Alok Kumar Pan

We consider the arrival time distribution defined through the quantum probability current for a Gaussian wave packet representing free particles in quantum mechanics in order to explore the issue of the classical limit of arrival time. We formulate the classical analogue of the arrival time distribution for an ensemble of free particles represented by a phas

J. P. Barjaktarevic, J. Links, G. J. Milburn, Ross H. McKenzie

We consider teleportation of an arbitrary spin-1/2 target quantum state along the ground state of a quantum spin chain. We present a decomposition of the Hilbert space of the many body quantum state into 4 vector spaces. Within each of these subspaces, it is possible to take any superposition of states, and use projective measurements to perform unit fidelit

Kenji Tomita

First the second-order perturbations of nonzero-Λcosmological models are derived with an arbitrary potential function of spatial coordinates, using the nonlinear version of Lifshitz&#39;s method in the synchronous gauge. Their expression is the generalization (to the nonzero-Λcase) of second-order perturbations in the Einstein-de Sitter model which were deri

Takeshi Chiba, Ryuichi Takahashi, Naoshi Sugiyama

We classify the future of the universe for general cosmological models including matter and dark energy. If the equation of state of dark energy is less then -1, the age of the universe becomes finite. We compute the rest of the age of the universe for such universe models. The behaviour of the future growth of matter density perturbation is also studied. We

Minu Joy, Ewan D. Stewart, Jinn-Ouk Gong, Hyun-Chul Lee

We propose a general inverse formula for extracting inflationary parameters from the observed power spectrum of cosmological perturbations. Under the general slow-roll scheme, which helps to probe the properties of inflation in a model independent way, we invert the leading order, single field, power spectrum formula. We also give some physically interesting

Zenji Hiroi, Shigeki Yonezawa, Takaki Muramatsu, Jun-Ichi Yamaura

Two beta-pyrochlore oxide superconductors, CsOs2O6 and RbOs2O6, are studied thermodynamically by measuring specific heat on polycrystalline samples. It is found that a Sommerfeld coefficient ? is nearly equal, 20 mJ/K2 mol Os, in the two oxides with different superconducting transition temperatures; Tc = 3.3 K and 6.3 K, respectively. This suggests that the

Maxim Raginsky

We consider the problem of nonlinear dimensionality reduction: given a training set of high-dimensional data whose ``intrinsic&#39;&#39; low dimension is assumed known, find a feature extraction map to low-dimensional space, a reconstruction map back to high-dimensional space, and a geometric description of the dimension-reduced data as a smooth manifold. We

Pradeep Kiran Sarvepalli, Andreas Klappenecker

We construct nonbinary quantum codes from classical generalized Reed-Muller codes and derive the conditions under which these quantum codes can be punctured. We provide a partial answer to a question raised by Grassl, Beth and Roetteler on the existence of q-ary quantum MDS codes of length n with q\le n\le q^2-1.

T. C. Ralph, A. J. F. Hayes, Alexei Gilchrist

We present a linear optics quantum computation scheme that employs a new encoding approach that incrementally adds qubits and is tolerant to photon loss errors. The scheme employs a circuit model but uses techniques from cluster state computation and achieves comparable resource usage. To illustrate our techniques we describe a quantum memory which is fault

M. Tumminello, A. Vaglica, G. Vetri

Rabi oscillations may be viewed as an interference phenomenon due to a coherent superposition of different quantum paths, like in the Young&#39;s two-slit experiment. The inclusion of the atomic external variables causes a non dissipative damping of the Rabi oscillations. More generally, the atomic translational dynamics induces damping in the correlation fu

A. Kwang-Hua Chu

We make comments on Gaidarzhy {\it et al.}&#39;s [{\it Phys. Rev. Lett.} 94, 030402 (2005)] letter.

Jesus Gomez-Gardenes, Yamir Moreno, Luis M. Floria

Biological networks have been recently found to exhibit many topological properties of the so-called complex networks. It has been reported that they are, in general, both highly skewed and directed. In this paper, we report on the dynamics of a Michaelis-Menten like model when the topological features of the underlying network resemble those of real biologi

V. M. Shabaev, K. Pachucki, I. I. Tupitsyn, V. A. Yerokhin

The complete gauge-invariant set of the one-loop QED corrections to the parity-nonconserving 6s-7s amplitude in $^{133}$Cs is evaluated to all orders in $αZ$ using a local version of the Dirac-Hartree-Fock potential. The calculations are peformed in both length and velocity gauges for the absorbed photon. The total binding QED correction is found to be -0.27

B. Abbott, P. Baringer, T. Bolton, Z. Greenwood

The D0 experiment at Fermilab's Tevatron will record several petabytes of data over the next five years in pursuing the goals of understanding nature and searching for the origin of mass. Computing resources required to analyze these data far exceed capabilities of any one institution. Moreover, the widely scattered geographical distribution of D0 collaborat

Subhasish Chakraborty1, Michael C. Parker2, Robert J. Mears3, David G Hasko1

A Fourier-space based design approach for the systematic control of single and multiple photon localization states in a 1D lattice is presented. Resultant lattices are aperiodic in nature, such that lattice periodicity is not a useful optimization parameter to achieve novel field localization characteristics. Instead, direct control of field localization com

John L. Spiesberger

Locating where transient signals travel between a source and receiver requires a final step that is needed after using a theory of diffraction such as the integral theorem of Helmholtz and Kirchhoff. Introduced here, the final step accounts for interference between adjacent apertures on a phase screen by adaptively adjusting their phase and amplitude, yieldi

M. Encinosa

An efficient procedure for generating Gram-Schmidt states on a toroidal surface $T^2$ is presented. As an application of the method, low-lying eigenvalues and wave functions for an electron on $T^2$ subjected to a constant magnetic field are determined.

P. Gawronski, P. Gronek, K. Kulakowski

The Heider balance is a state of a group of people with established mutual relations between them. These relations, friendly or hostile, can be measured in the Bogardus scale of the social distance. In previous works on the Heider balance, these relations have been described with integers 0 and $\pm1$. Recently we have proposed real numbers instead. Also, di

B. Rothenstein, A. De Sabata

Transformation equations for physical quantities that characterize plane electromagnetic wave propagation in transparent optical media are presented. The Doppler effect, and measurements performed by an observer moving with the wave are also considered. The results, not mentioned in introductory Physics textbooks, are simple to derive and could be used in un

Alberto Maurizi

In this short review it is suggested that the relationship between third- and fourth-order moments of turbulence in the atmospheric boundary layer depends on stability. This can explain some differences among datasets, and provides a key point for modelling improvement.

Sarika Bhattacharyya, Biman Bagchi

The origin of the microscopic motions that lead to stress relaxation in deeply supercooled liquid remains unclear. We show that in such a liquid the stress relaxation is locally anisotropic which can serve as the driving force for the hopping of the system on its free energy surface. However, not all hopping are equally effective in relaxing the local stress

Yong-Fan Chen, Zen-Hsiang Tsai, Yu-Chen Liu, Ite A. Yu

We report an experimental demonstration of single-photon switching in laser-cooled $^{87}$Rb atoms. A resonant probe pulse with an energy per unit area of one photon per $λ^2/2π$ propagates through the optically thick atoms. Its energy transmittance is greater than 63% or loss is less than $e^{-1}$ due to the effect of electromagnetically induced transparenc

Alexander L. Kholmetskii

This paper inspects more closely the problem of the momentum and energy of a bound (non-radiating) electromagnetic (EM) field. It has been shown that for an isolated system of non-relativistic mechanically free charged particles a transformation of mechanical to EM momentum and vice versa occurs in accordance with the requirement PG=const, where PG is the ca

Edward W. Piotrowski, Marcin Makowski

We study a simple example of a sequential game illustrating problems connected with making rational decisions that are universal for social sciences. The set of chooser&#39;s optimal decisions that manifest his preferences in case of a constant strategy of the adversary (the offering player), is investigated. It turns out that the order imposed by the player

M. A. G. Alvarez, N. Alamanos, L. C. Chamon, M. S. Hussein

Elastic scattering angular distributions for systems with reduced mass between 3 and 34 and energies varying between 25 and 120 MeV/nucleon were analyzed. The stable $^4$He, its exotic partner $^6$He, and the weakly bound $^{6,7}$Li nuclei were included as projectiles in the systematics. Optical model data analyzes were performed with an adjustable factor of

Alberto Mengoni

The method for an experimental determination of the stellar enhancement factor for the cross section of the $^{151}$Sm$(n,γ)$ reaction process is proposed. This study offered the pretext for an excursus on the interconnections between capture and dissociation reactions and the interplay between theory and experiments in the determination of neutron capture c

C. Markert

The resonance production of $Δ$, K(892), $Σ$(1385), $Λ$(1520) and $ϕ$ from elementary p+p and Au+Au collisions at $\sqrt{s_{\rm NN}} = $ 200 GeV from the STAR experiment at RHIC is presented. Yields and spectra are discussed in terms of chemical and thermal freeze-out conditions. Thermal models do not describe sufficiently the yields of the resonance product

Huan Z. Huang

We present experimental features of identified particle production from nucleus-nucleus collisions at RHIC. These features reflect hadronization from a deconfined partonic matter whose particle formation scheme is distinctly different from fragmentation phenomenology in elementary collisions. Multi-parton dynamics, such as quark coalescences or recombination

I. Zychor, V. Koptev, M. Buescher, A. Dzyuba

The reaction pp->pK+Y has been studied with the ANKE spectrometer at COSY-Juelich in order to investigate heavy hyperon production. The missing mass spectra MM(pK+) have been analyzed and compared with Monte Carlo simulations. Indications for a hyperon resonance Y0*(1480) have been found.

J. C. Cornell, the SPIRAL Collaboration

The production and acceleration of Radioactive Ion Beams (RIBs) is today an area of intense interest. The history and development of RIB facilities in Europe is presented, with discussion of both the in-flight and ISOL methods used at different laboratories. The current status of present developments like the SPIRAL II facility at GANIL and the FAIR in-fligh

L. Biferale, G. Boffetta, A. Celani, B. J. Devenish

We present a detailed investigation of the particle pair separation process in homogeneous isotropic turbulence. We use data from direct numerical simulations up to Taylor&#39;s Reynolds number 280 following the evolution of about two million passive tracers advected by the flow over a time span of about three decades. We present data for both the separation

N. Lazarides, G. P. Tsironis

For an isotropic and homogeneous nonlinear left-handed materials, for which the effective medium approximation is valid, Maxwell&#39;s equations for electric and magnetic fields lead naturally, within the slowly varying envelope approximation, to a system of coupled nonlinear Schroedinger equations. This system is equivalent to the well-known Manakov model t

Kenji Kajiwara, Tetsu Masuda, Masatoshi Noumi, Yasuhiro Ohta

Hypergeometric solutions to the q-Painlevé equations are constructed by direct linearization of disrcrete Riccati equations. The decoupling factors are explicitly determined so that the linear systems give rise to q-hypergeometric equations.

Ivan G. Avramidi

We review the construction of the Dirac operator and its properties in Riemannian geometry and show how the asymptotic expansion of the trace of the heat kernel determines the spectral invariants of the Dirac operator and its index. We also point out that the Einstein-Hilbert functional can be obtained as a linear combination of the first two spectral invari

Tom Claeys, Arno B. J. Kuijlaars

We study unitary random matrix ensembles in the critical case where the limiting mean eigenvalue density vanishes quadratically at an interior point of the support. We establish universality of the limits of the eigenvalue correlation kernel at such a critical point in a double scaling limit. The limiting kernels are constructed out of functions associated w

Christopher J. Fewster

Quantum fields are known to violate all the pointwise energy conditions of classical general relativity. We review the subject of quantum energy inequalities: lower bounds satisfied by weighted averages of the stress-energy tensor, which may be regarded as the vestiges of the classical energy conditions after quantisation. Contact is also made with thermodyn

Guowu Meng

Let $ϕ$ be a polynomial over $K$ (a field of characteristic 0) such that the Hessian of $ϕ$ is a nonzero constant. Let $\barϕ$ be the formal Legendre Transform of $ϕ$. Then $\barϕ$ is well-defined as a formal power series over $K$. The Hessian Conjecture introduced here claims that $\barϕ$ is actually a polynomial. This conjecture is shown to be true when $K

Stefano Vidussi

The purpose of this paper is to present some results on the existence of homologous, nonisotopic symplectic or lagrangian surfaces embedded in a simply connected symplectic 4-dimensional manifold.

David M. Bradley

The double zeta function was first studied by Euler in response to a letter from Goldbach in 1742. One of Euler&#39;s results for this function is a decomposition formula, which expresses the product of two values of the Riemann zeta function as a finite sum of double zeta values involving binomial coefficients. In this note, we establish a q-analog of Euler

Hacen Dib

Using Bessel-Muirhead system, we can express the K-bessel function defined on a Jordan algebra as linear combination of the J-solutions. We determine explicitly the coefficients when the rank of this Jordan algebra is three after a reduction to the rank two. The main tools are some algebraic identities developed for the occasion.

Alberto Calabri, Ciro Ciliberto, Margarida Mendes Lopes

Minimal algebraic surfaces of general type with the smallest possible invariants have geometric genus zero and K^2=1 and are usually called &#34;numerical Godeaux surfaces&#34;. Although they have been studied by several authors, their complete classification is not known. In this paper we classify numerical Godeaux surfaces with an involution, i.e. with an

C. A. Rossi

In this short note, we investigate some features of the space $\Inject{d}{m}$ of linear injective maps from $\bbR^d$ into $\bbR^m$; in particular, we discuss in detail its relationship with the Stiefel manifold $V_{m,d}$, viewed, in this context, as the set of orthonormal systems of $d$ vectors in $\bbR^m$. Finally, we show that the Stiefel manifold $V_{m,d}

S Launois, T H Lenagan, L Rigal

We prove a general theorem showing that iterated skew polynomial extensions of the type which fit the conditions needed by Cauchon&#39;s deleting derivations theory and by the Goodearl-Letzter stratification theory are unique factorisation rings in the sense of Chatters and Jordan. This general result applies to many quantum algebras; in particular, generic

D. R. Yafaev

Consider the scattering amplitude $s(ω,ω^\prime;λ)$, $ω,ω^\prime\in{\Bbb S}^{d-1}$, $λ> 0$, corresponding to an arbitrary short-range magnetic field $B(x)$, $x\in{\Bbb R}^d$. This is a smooth function of $ω$ and $ω^\prime$ away from the diagonal $ω=ω^\prime$ but it may be singular on the diagonal. If $d=2$, then the singular part of the scattering amplitude

K. Ichikawa, T. Noda

In this paper, we study stability for harmonic foliations on locally conformal Kähler manifolds with complex leaves. We also discuss instability for harmonic foliations on compact submanifolds immersed in Euclidean spaces and compact homogeneous spaces.

A. Yu. Olshanskii, Mark Sapir

We construct a group (an HNN extension of a free group) with polynomial isoperimetric function, linear isodiametric function and non-simply connected asymptotic cones.

F. Dahmani, A. Yaman

We prove that, if a group is relatively hyperbolic, the parabolic subgroups are virtually nilpotent if and only if there exists a hyperbolic space with bounded geometry on which it acts geometrically finitely. This provides, by use of M. Bonk and O. Schramm embedding theorem, a very short proof of the finiteness of asymptotic dimension of relatively hyperbol

Shunsuke Takagi

We prove a generalization of Demailly-Ein-Lazarsfeld&#39;s subadditivity formula and Mustata&#39;s summation formula for multiplier ideals to the case of singular varieties, using characteristic $p$ methods. As an application of our formula, we improve Hochster-Huneke&#39;s result on the growth of symbolic powers of ideals in singular affine algebras.

Sonja Lj. Cukic, Dmitry N. Kozlov

The main result of this paper is a proof of the following conjecture of Babson & Kozlov: Theorem. Let G be a graph of maximal valency d, then the complex Hom(G,K_n) is at least (n-d-2)-connected. Here Hom(-,-) denotes the polyhedral complex introduced by Lovász to study the topological lower bounds for chromatic numbers of graphs. We will also prove, as a co

Tony J. Puthenpurakal

We study Hilbert functions of maximal Cohen-Macaulay(=CM) modules over CM local rings. We show that if $A$ is a hypersurface ring with dimension $d > 0$ then the Hilbert function of $M$ \wrt $\m$ is non-decreasing. If $A = Q/(f)$ for some regular local ring $Q$, we determine a lower bound for $e_0(M)$ and $e_1(M)$. We analyze the case when equality holds and

Qi Zhang

In this paper, we give an affirmative answer to a conjecture in the Minimal Model Program. We prove that log $Q$-Fano varieties of dim $n$ are rationally connected. We also study the behavior of the canonical bundles under projective morphisms.

J. Phillips

The N = 1 superfield formalism in four-dimensions is well formulated and understood, yet there remain unsolved problems. In this thesis, superfield actions for free massless and massive higher spin superfield theories are formulated in four dimensions. The discussion of massless models is restricted to half integer superhelicity. These models describe multip

Liam McAllister

Inflationary models whose vacuum energy arises from a D-term are believed not to suffer from the supergravity eta problem of F-term inflation. That is, D-term models have the desirable property that the inflaton mass can naturally remain much smaller than the Hubble scale. We observe that this advantage is lost in models based on string compactifications who

D. Bashkirov, G. Sardanashvily

Quantization of gravitation theory as gauge theory of general covariant transformations in the framework of Batalin-Vilkoviski (BV) formalism is considered. Its gauge-fixed Lagrangian is constructed.

Cristine N. Ferreira, Helder Chavez, Jose A. Helayel-Neto

In this letter, we reconsider the delicate issue of symmetry and supersymmetry breakings for gauge theories with gauge-field mixings. The purpose is to study generalyzed potentials in the presence of more than a single gauge potential. In this work, following a stream of investigation on supersymmetric gauge theories without flat directions, we contemplate t

M. Cavaglia&#39;, G. De Risi, M. Gasperini

We discuss the cosmological amplification of tensor perturbations in a simple example of brane-world scenario, in which massless gravitons are localized on a higher-dimensional Kasner-like brane embedded in a bulk AdS background. Particular attention is paid to the canonical normalization of the quadratic action describing the massless and massive vacuum qua

Shun-Jin Wang, Shan-Gui Zhou, Hans-Christian Pauli

The missed particle-antiparticle degrees of freedom are retrieved and the corresponding particle-antiparticle intrinsic space are introduced to study the dynamical symmetry of the Dirac particle. As a result, the particle-antiparticle quantum number appears naturally and the Dirac particle has five quantum numbers instead of four. An anti-symmetry (different

Miguel Tierz

We study analytical aspects of a generic q-deformation with q real, by relating it with discrete scale invariance. We show how models of conformal quantum mechanics, in the strong coupling regime and after regularization, are also discrete scale invariant. We discuss the consequences of their distinctive spectra, characterized by functional behavior. The rol

John Ellis, Keith A. Olive, Yudi Santoso, Vassilis C. Spanos

We compare updated predictions for the elastic scattering of supersymmetric neutralino dark matter with the improved experimental upper limit recently published by CDMS II. We take into account the possibility that the π-nucleon Σterm may be somewhat larger than was previously considered plausible, as may be supported by the masses of exotic baryons reported

Neil D. Christensen, Robert Shrock

We point out that if quark and lepton masses arise dynamically, then in a wide class of theories the corresponding running masses $m_{f_j}(p)$ exhibit the power-law decay $m_{f_j}(p) \propto Λ_j^2/p^2$ for Euclidean momenta $p >> Λ_j$, where $f_j$ is a fermion of generation $j$, and $Λ_j$ is the maximal scale relevant for the origin of $m_{f_j}$. We estimate

Andrea Dainese

With the acceleration of lead nuclei in the LHC, heavy-ion physics will enter a new energy domain. One of the main novelties introduced by the 30-fold energy-jump from RHIC to the LHC is the abundant heavy-quark production. After discussing a few examples of physics issues that can be addressed using heavy quarks, we present a selection of results on the exp

Andrea Dainese

D-meson suppression in Pb-Pb collisions at the LHC due to charm quark in-medium energy loss is estimated within a model that describes the available quenching measurements at RHIC. The result is compared to that previously published by the author. The expected sensitivity of the ALICE experiment for studying charm energy loss via fully-reconstructed D^0-meso

Shi-Yuan Li

In relativistic heavy ion collisions, the cross section of heavy hadron production via the combination of a heavy quark with a light one from the quark-gluon matter can be factorized. It is the convolution of twist-4 combination matrix elements, the parameters corresponding to the parton distributions of the quark-gluon matter, as well as the hard partonic c

J. R. Cudell, A. Lengyel, E. Martynov, O. V. Selyugin

We review the evidence for the presence of a hard singularity in soft forward amplitudes, and give an estimate of its trajectory and couplings.

M. A. Cakir, S. Mutlu, L. Solmaz

We present a through discussion of motivations for and phenomenological issues in supersymmetric models with minimal matter content and non-holomorphic soft-breaking terms. Using the unification of the gauge couplings and assuming SUSY is broken with non-standard soft terms, we provide semi-analytic solutions of the RGEs for low and high choices of tanβwhich

Hou Defu

We study shear viscosity in weakly coupled hot pure gauge field QCD theory basing on transport theory and the Kubo formula using the closed time path formalism (CTP) of real time finite temperature field theory. We show that the viscosity can be obtained as the integral of a retarded three-point function. Non-perturbative corrections to the bare one loop res