April 2003 arXiv papers — page 12

Henri Kowalski, Derek Teaney

We develop a dipole model for HERA DIS data which incorporates the impact parameter distribution of the proton. The model describes the inclusive total $γ^*p$ cross-sections as well as the diffractive $J/ψ$ differential cross-sections. We compare the model with previous approaches and show that the $t$-distributions are sensitive to saturation phenomena. We

Luk C. Yeung, Gastone C. Castellani, Harel Z. Shouval

The influx of calcium ions into the dendritic spines through the N-metyl-D-aspartate (NMDA) channels is believed to be the primary trigger for various forms of synaptic plasticity. In this paper, the authors calculate analytically the mean values of the calcium transients elicited by a spiking neuron undergoing a simple model of ionic currents and back-propa

Congwu Cui, Trevor A. Tyson, Zhiqiang Chen, Zhong Zhong

Pressure effects on the electron transport and structure of Nd1-xSrxMnO3 (x = 0.45, 0.5) were investigated in the range from ambient to ~6 GPa. In Nd0.55Sr0.45MnO3, the low-temperature ferromagnetic metallic state is suppressed and a low temperature insulating state is induced by pressure. In Nd0.5Sr0.5MnO3, the CE-type antiferromagnetic charge-ordering stat

A. J. Bracken

Entanglement is defined for each vector subspace of the tensor product of two finite-dimensional Hilbert spaces, by applying the notion of operator entanglement to the projection operator onto that subspace. The operator Schmidt decomposition of the projection operator defines a string of Schmidt coefficients for each subspace, and this string is assumed to

Kazuo Iwama, Akinori Kawachi, Hiroyuki Masuda, Raymond H. Putra

Our problem is to evaluate a multi-valued Boolean function $F$ through oracle calls. If $F$ is one-to-one and the size of its domain and range is the same, then our problem can be formulated as follows: Given an oracle $f(a,x): \{0,1\}^n\times\{0,1\}^n \to \{0,1\}$ and a fixed (but hidden) value $a_0$, we wish to obtain the value of $a_0$ by querying the ora

Pramod Kumar Singh, Amreesh Chandra

The dispersal of high dielectric constant ferroelectric ceramic material Ba(0.7)Sr(0.3)TiO(3) (Tc~30 C) and Ba(0.88)Sr(0.12)TiO(3) (Tc~90 C) in an ion conducting polymer electrolyte (PEO:NH4I) is reported to result in an increase in the room temperature ionic conductivity by two orders of magnitude. The conductivity enhancememt "peaks" as we approach

Colm Connaughton, Sergey Nazarenko, Alan C. Newell

In the study of weakly turbulent wave systems possessing incomplete self-similarity it is possible to use dimensional arguments to derive the scaling exponents of the Kolmogorov-Zakharov spectra, provided the order of the resonant wave interactions responsible for nonlinear energy transfer is known. Furthermore one can easily derive conditions for the breakd

Colm Connaughton, Alan C. Newell, Yves Pomeau

The evolution of the Kolmogorov-Zakharov (K-Z) spectrum of weak turbulence is studied in the limit of strongly local interactions where the usual kinetic equation, describing the time evolution of the spectral wave-action density, can be approximated by a PDE. If the wave action is initially compactly supported in frequency space, it is then redistributed by

L. Trache, A. Azhari, F. Carstoiu, H. L. Clark

Asymptotic normalization coefficients (ANCs) for 8Li->7Li+n have been extracted from the neutron transfer reaction 13C(7Li,8Li)12C at 63 MeV. These are related to the ANCs in 8B->7Be+p using charge symmetry. We extract ANCs for 8B that are in very good agreement with those inferred from proton transfer and breakup experiments. We have also separated the cont

A. Bazilevsky

We present PHENIX recent results on charged particle and transverse energy densities measured at mid-rapidity in Au-Au collisions at $\sqrt{s_{_{NN}}}$=130 GeV and 200 GeV over broad range of centralities. The mean transverse energy per charged particle is derived. The first PHENIX measurements at $\sqrt{s_{_{NN}}}$=19.6 GeV are also presented. A comparison

Alexander Yu. Vlasov

Transformation properties of Dirac equation correspond to Spin(3,1) representation of Lorentz group SO(3,1), but group GL(4,R) of general relativity does not accept a similar construction with Dirac spinors. On the other hand, it is possible to look for representation of GL(4,R) in some bigger space, there Dirac spinors are formally situated as some "sub

Alexei D. Miasnikov

The Andrews-Curtis conjecture claims that every balanced presentation of the trivial group can be transformed into the trivial presentation by a finite sequence of "elementary transformations" which are Nielsen transformations together with an arbitrary conjugation of a relator. It is believed that the Andrews-Curtis conjecture is false; however, not

Alexei D. Miasnikov, Alexei G. Myasnikov

The Andrews-Curtis conjecture states that every balanced presentation of the trivial group can be reduced to the standard one by a sequence of the elementary Nielsen transformations and conjugations. In this paper we describe all balanced presentations of the trivial group on two generators and with the total length of relators <= 12. We show that all these

Vadim Schechtman

Sganarelle: ... Mais encore faut-il croire quelque chose dans le monde: qu&#39;est-ce donc que vous croyez? Dom Juan: Ce que je crois? Sganarelle: Oui. Dom Juan: Je crois que deux et deux sont quatre, Sganarelle, et que quatre et quatre sont huit. [Molière, Dom Juan] One dicusses sheaves of vertex algebras over smooth varieties and their connections with cha

Shigeru Mukai

A K3 surface is a quaternionic analogue of an elliptic curve from a view point of moduli of vector bundles. We can prove the algebraicity of certain Hodge cycles and a rigidity of curve of genus eleven and gives two kind of descriptions of Fano threefolds as applications. In the final section we discuss a simplified construction of moduli spaces.

Lothar Göttsche

The Hilbert scheme $S^{[n]}$ of points on an algebraic surface $S$ is a simple example of a moduli space and also a nice (crepant) resolution of singularities of the symmetric power $S^{(n)}$. For many phenomena expected for moduli spaces and nice resolutions of singular varieties it is a model case. Hilbert schemes of points have connections to several fiel

Shicheng Wang

First the title could be also understood as ``3-manifolds related by non-zero degree maps&#34; or &#34;Degrees of maps between 3-manifolds&#34; for some aspects in this survey talk. The topology of surfaces was completely understood at the end of 19th century, but maps between surfaces kept to be an active topic in the 20th century and many important results

Ulrike Tillmann

Twenty years ago, Mumford initiated the systematic study of the cohomology ring of moduli spaces of Riemann surfaces. Around the same time, Harer proved that the homology of the mapping class groups of oriented surfaces is independent of the genus in low degrees, increasing with the genus. The (co)homology of mapping class groups thus stabelizes. At least ra

Peter Teichner

We explain new developments in classical knot theory in 3 and 4~dimensions, i.e. we study knots in 3-space, up to isotopy as well as up to concordance. In dimension~3 we give a geometric interpretation of the Kontsevich integral (joint with Jim Conant), and in dimension 4 we introduce new concordance invariants using von Neumann signatures (joint with Tim Co

Eleny-Nicoleta Ionel

Gromov-Witten invariants of a symplectic manifold are a count of holomorphic curves. We describe a formula expressing the GW invariants of a symplectic sum $X# Y$ in terms of the relative GW invariants of $X$ and $Y$. This formula has several applications to enumerative geometry. As one application, we obtain new relations in the cohomology ring of the modul

Lars Hesselholt

The cyclotomic trace of Bökstedt-Hsiang-Madsen, the subject of Bökstedt&#39;s lecture at the congress in Kyoto, is a map of pro-abelian groups K_*(A) -> TR_*^.(A;p) from Quillen&#39;s algebraic K-theory to a topological refinement of Connes&#39; cyclic homology. Over the last decade, our understanding of the target and its relation to K-theory has been signi

Burt Totaro

I will discuss recent progress by many people in the program of extending natural topological invariants from manifolds to singular spaces. Intersection homology theory and mixed Hodge theory are model examples of such invariants. The past 20 years have seen a series of new invariants, partly inspired by string theory, such as motivic integration and the ell

Mikio Furuta

In low dimensional topology, we have some invariants defined by using solutions of some nonlinear elliptic operators. The invariants could be understood as Euler class or degree in the ordinary cohomology, in infinite dimensional setting. Instead of looking at the solutions, if we can regard some kind of homotopy class of the operator itself as an invariant,

Yuri Chekanov

We present two different constructions of invariants for Legendrian knots in the standard contact space $\R^3$. These invariants are defined combinatorially, in terms of certain planar projections, and are useful in distinguishing Legendrian knots that have the same classical invariants but are not Legendrian isotopic.

Mladen Bestvina

We will survey the work on the topology of $Out(F_n)$ in the last 20 years or so. Much of the development is driven by the tantalizing analogy with mapping class groups. Unfortunately, $Out(F_n)$ is more complicated and less well-behaved. Culler and Vogtmann constructed Outer Space $X_n$, the analog of Teichmüller space, a contractible complex on which $Out(

V. I. Danilov, G. A. Koshevoy

In this paper we develop a theory of convexity for a free Abelian group M (the lattice of integer points), which we call theory of discrete convexity. We characterize those subsets X of the group M that could be call &#34;convex&#34;. One property seems indisputable: X should coincide with the set of all integer points of its convex hull co(X) (in the ambien

Alexander V. Karzanov

Let $G=(V(G),E(G))$ be a planar digraph embedded in the plane in which all inner faces are equilateral triangles (with three edges in each), and let the union $\Rscr$ of these faces forms a convex polygon. The question is: given a function $σ$ on the boundary edges of $G$, does there exist a concave function $f$ on $\Rscr$ which is affinely linear within eac

Eugenia Cheng

This paper follows from two earlier works. In the first we gave an explicit construction of opetopes, the underlying cell shapes in the theory of opetopic n-categories; at the heart of this construction is the use of certain trees. In the second we gave a description of trees using Kelly-Mac Lane graphs. In the present paper we apply the latter to the former

Eugenia Cheng

We give a precise description of combed trees in terms of Kelly-Mac Lane graphs. We show that any combed tree is uniquely expressed as an allowable Kelly-Mac Lane graph of a certain shape. Conversely, we show that any such Kelly-Mac Lane graph uniquely defines a combed tree.

Eugenia Cheng

We address the fact that composition in an opetopic weak n-category is in general not unique and hence is not a well-defined operation. We define composition with a given k-cell in an n-category by a span of (n-k)-categories. We characterise such a cell as universal if its composition span gives an equivalence of (n-k)-categories.

Eugenia Cheng

We continue our previous modifications of the Baez-Dolan theory of opetopes to modify the Baez-Dolan definition of universality, and thereby the category of opetopic n-categories and lax functors. For the case n=2 we exhibit an equivalence between this category and the category of bicategories and lax functors. We examine notions of strictness in the opetopi

Eugenia Cheng

We give an explicit construction of the category Opetope of opetopes. We prove that the category of opetopic sets is equivalent to the category of presheaves over Opetope.

Eugenia Cheng

We define the category of tidy symmetric multicategories. We construct for each tidy symmetric multicategory Q a cartesian monad (E_Q,T_Q) and extend this assignation to a functor. We exhibit a relationship between the slice construction on symmetric multicategories, and the `free operad&#39; monad construction on suitable monads. We use this to give an expl

Eugenia Cheng

We generalise the concepts introduced by Baez and Dolan to define opetopes constructed from symmetric operads with a category, rather than a set, of objects. We describe the category of 1-level generalised multicategories, a special case of the concept introduced by Hermida, Makkai and Power, and exhibit a full embedding of this category in the category of s

Eero Hyry, Karen E. Smith

We find formulas for the graded core of certain m-primary ideals in a graded ring. In particular, if S is the section ring of an ample line bundle on a Cohen-Macaulay complex projective variety, we show that under suitable hypothesis, the core and graded core of the ideal of S generated by all elements of degrees at least N (for some, equivalently every, lar

Olivier Schiffmann

A short informal survey on the topics listed in the title. For the proceedings of the International Conference on Rings and Algebras X.

M. Beattie, S. Dăscălescu

Let H be a finite dimensional non-semisimple Hopf algebra over an algebraically closed field k of characteristic 0. If H has no nontrivial skew-primitive elements, we find some bounds for the dimension of H_1, the second term in the coradical filtration of H. Using these results, we are able to show that every Hopf algebra of dimension 14 is semisimple and t

Dany-Jack Mercier

We provide a systematic study of sesquilinear hermitian forms and a new proof of the calculus of some exponential sums defined with quadratic hermitian forms. The computation of the number of solutions of equations such as Tr(f(x)+v.x)=0 or Tr(f(x))=a allows us to construct codes and to obtain their parameters.

John M. Cornwall

We offer a physicists&#39; proof that center-vortex theory requires the area in the Wilson-loop area law to involve an extremal area. Area-law dynamics is determined by integrating over Wilson loops only, not over surface fluctuations for a fixed loop. Fluctuations leading to to perimeter-law corrections come from loop fluctuations as well as integration ove

Eric G. Gimon, Akikazu Hashimoto

We find exact rotating and non-rotating neutral black hole solutions in the Godel universe of the five dimensional minimal supergravity theory. We also describe the embedding of this solution in M-theory. After dimensional reduction and T-duality, we obtain a supergravity solution corresponding to placing a black string in a pp-wave background.

Chanju Kim, Yoonbai Kim, Chong Oh Lee

We study Born-Infeld type tachyonic effective action of unstable D2-brane with a runaway potential and find rich structure of static regular solitonic solutions. There exists only periodic array of tachyon kink-antikinks in pure tachyonic theory, however, in the presence of electromagnetic fields, solutions include periodic arrays, topological tachyon kinks,

Nail R. Khusnutdinov

Smooth-throat wormholes are treated on as possessing quantum fluctuation energy with scalar massive field as its source. Heat kernel coefficients of the Laplace operator are calculated in background of the arbitrary-profile throat wormhole with the help of the zeta-function approach. Two specific profile are considered. Some arguments are given that the worm

J. M. Isidro

We study the quantisation of complex, finite-dimensional, compact, classical phase spaces C, by explicitly constructing Hilbert-space vector bundles over C. We find that these vector bundles split as the direct sum of two holomorphic vector bundles: the holomorphic tangent bundle T(C), plus a complex line bundle N(C). Quantum states (except the vacuum) appea

A. I. Nikishov

Scattering and electron-positron pair production by a one-dimensional potential is considered in the framework of the $S-$matrix formalism. The solutions of the Dirac equation are classified according to frequency sign. The Bogoliubov transformation relating the in- and out-states are given. We show that the norm of a solution of the wave equation is determi

Takao Suyama

We use the low energy effective theory of string theory to investigate condensations of closed string tachyons propagating in the bulk. The c-function is related to the total energy of the system via the effective action. A possible modification of the c-theorem is discussed. We also deduce endpoints of the decays by investigating scalar potential of gauged

M. I. Beciu

We combine the creation and annihilation operators of a scalar field in Minkowski spacetime to obtain the generators of the SU(1,1). We show that the transformation between Minkowski and Rindler vacua can be represented by (pseudo)rotation in the space of the SU(1,1) group. The root of this fact originates from the coordinate transformation between Minkowski

G. V. Efimov

The Bethe-Salpeter (BS) equation in the ladder approximation is studied within a scalar theory: two scalar fields (constituents) with mass $m$ interacting via an exchange of a scalar field (tieon) with mass $μ$. The BS equation is written in the form of an integral equation in the configuration Euclidean $x$-space with the kernel which for stable bound state

Ignacio Bediaga, Marina Nielsen

We consider the nonleptonic and semileptonic decays of $D_s$-mesons into $ϕ$ and $f_0(980)$ mesons. QCD sum rules are used to calculate the form factors associated with these decays, and the correspondig decay rates. On the basis of data on $D_s^+\toπ^+π^+π^-$, which goes dominantly via the transition $D_s^+\to π^+f_0(980)$, we conclude that there is space f

Mu-Lin Yan, Yi-Bin Huang, Xiao-Jun Wang

We study the relation between the scale of chiral symmetry spontaneously breaking and constituent quark mass. We argue that this relation partly reveals strong interaction origination of chiral symmetry breaking. We show that the relation can be obtained via checking unitarity region of low-energy effective field theory of QCD. This effective field theory mu

Ya. D. Krivenko-Emetov

The $F_{2}$ structure functions of the inelastic lepton-hadron scattering is calculated in the case of non-zero intermediate gluon-quarks self-energy $M_{gq}^{2}$ and quasielastic limit. It is shown that in the quasielastic limit the evolution equation can been solved in case massive particles as QCD ladder calculation results. The intermediate gluon-quarks

Shinji Takeda, Sinya Aoki, Kiyotomo Ide

We determine O($a$) boundary improvement coefficients up to 1-loop level for the Schrödinger Functional coupling with improved gauge actions including plaquette and rectangle loops. These coefficients are required to implement 1-loop O($a$) improvement in full QCD simulations for the coupling with the improved gauge actions. To this order, lattice artifacts

Subenoy Chakraborty, Ujjal Debnath

In this paper we present a class of exact inhomogeneous solutions to Einstein&#39;s equations for higher dimensional Szekeres metric with perfect fluid and a cosmological constant. We also show particular solutions depending on the choices of various parameters involved and for dust case. Finally, we examine the asymptotic behaviour of some of these solution

Lillian Lee

A brief, general-audience overview of the history of natural language processing, focusing on data-driven approaches.Topics include &#34;Ambiguity and language analysis&#34;, &#34;Firth things first&#34;, &#34;A &#39;C&#39; change&#34;, and &#34;The empiricists strike back&#34;.

V. V. Kondratenko, Yu. A Kuperin

This paper reports empirical evidence that a neural networks model is applicable to the statistically reliable prediction of foreign exchange rates. Time series data and technical indicators such as moving average, are fed to neural nets to capture the underlying &#34;rules&#34; of the movement in currency exchange rates. The trained recurrent neural network

Chris P. Search, Pierre Meystre

We discuss the possibility of phase-conjugation of an atomic Fermi field via nonlinear wave mixing in an ultracold gas. It is shown that for a beam of fermions incident on an atomic phase-conjugate mirror, a time reversed backward propagating fermionic beam is generated similar to the case in nonlinear optics. By adopting an operational definition of the pha

J. S. Andrade, H. F. da Silva, M. Baquil, B. Sapoval

We investigate through molecular dynamics the transition from Knudsen to molecular diffusion transport towards 2d absorbing interfaces with irregular geometry. Our results indicate that the length of the active zone decreases continuously with density from the Knudsen to the molecular diffusion regime. In the limit where molecular diffusion dominates, we fin

M. L. Foo, R. E. Schaak, V. L. Miller, T. Klimczuk

The layered sodium cobalt oxyhydrate superconductor Na0.3CoO2*1.4H2O is shown through X-ray diffraction and thermogravimetric studies to be one of a series of hydrated phases of Na0.3CoO2. Further, it is shown that the material is exceptionally sensitive to both temperature and humidity near ambient conditions, easily dehydrating to a non-superconducting low

O. Waldmann

For powder samples of polynuclear metal complexes the dependence of the inelastic neutron scattering intensity on the momentum transfer Q is known to be described by a combination of so called interference terms. They reflect the interplay between the geometrical structure of the compound and the spatial properties of the wave functions involved in the trans

J. Quintanilla, B. L. Gyorffy

We revisit the old problem of exotic superconductivity as Cooper pairing with finite angular momentum emerging from a central potential. Based on some general considerations, we suggest that the phenomenonn is associated with interactions that keep electrons at some particular, finite distance (r_{0}), and occurs at a range of intermediate densities (n\sim 1

Kazutaka Nagao, J. B. Neaton, N. W. Ashcroft

The structural, electronic, and adhesive properties of Cu/SiO$_2$ interfaces are investigated using first-principles density-functional theory within the local density approximation. Interfaces between fcc Cu and $α$-cristobalite(001) surfaces with different surface stoichiometries are considered. Interfacial properties are found to be sensitive to the choic

B. T. Jonker, A. T. Hanbicki, D. T. Pierce, M. D. Stiles

The different conventions used in the semiconductor and magnetic metals communities can cause confusion in the context of spin polarization and transport in simple heterostructures. In semiconductors, terminology is based on the orientation of the electron spin, while in magnetic metals it is based on the orientation of the moment. In the rapidly expanding f

F. Rivadulla, J. S. Zhou, J. B. Goodenough

We report measurement of room-temperature compressibility, thermal expansion, thermoelectric power a(T) at various pressures P < 20 kbar, basal-plane resistivity rab (T), magnetic susceptibility and thermal conductivity k(T) taken on single-crystal or cold-pressed Na0.57CoO2. An enhancement of a large thermopower with a change of slope occurs on heating near

M. D. Grynberg

The dynamics of a one dimensional growth model involving attachment and detachment of particles is studied in the presence of a localized growth inhomogeneity along with anchored boundary conditions. At large times, the latter enforce an equilibrium stationary regime which allows for an exact calculation of roughening exponents. The stochastic evolution is r

Hiroshi Kontani

We present a theoretical study on the superconductivity in β&#39;-(BEDT-TTF)_2ICl_2 at Tc=14.2K under high hydrostatic pressure found by Taniguchi et al., which is the highest record among organic superconductors. Its electronic structure is well expressed by the anisotropic triangular lattice Hubbard model at half filling. In the present work, we study this

Kyungsik Kim, Seong-Min Yoon, Yup Kim

The herd behaviors of returns for the won-dollar exchange rate and the KOSPI are analyzed in Korean financial markets. It is shown that the probability distribution $P(R)$ of price returns $R$ for three values of the herding parameter tends to a power-law behavior $P(R) \simeq R^{-β}$ with the exponents $ β=2.2$(the won-dollar exchange rate) and 2.4(the KOSP

Peter M. Woods

Soft Gamma Repeaters (SGRs) undergo changes in their pulse properties and persistent emission during episodes of intense burst activity. Both SGR 1900+14 and SGR 1806-20 have shown significant changes in their spin-down rates during the last several years, yet the bulk of this variability is not correlated with burst activity. SGR 1900+14 has undergone large

Daniel A. Dale, Juan M. Uson

We have obtained new optical imaging and spectroscopic observations of 78 galaxies in the fields of the rich clusters Abell 1413 (z = 0.14), Abell 2218 (z = 0.18) and Abell 2670 (z = 0.08). We have detected line emission from 25 cluster galaxies plus an additional six galaxies in the foreground and background, a much lower success rate than what was found (6

Reuven Opher

What are the important unanswered questions in cosmology? The choice as to which are the most important is somewhat personal. In the view of the author, the ten topics chosen here for discussion must be included among the most fundamental. Present cosmological theory is unable to fully describe the evolution of the universe from the time of the Big Bang and

Michael R. Collier, Thomas E. Moore, David Simpson, Aaron Roberts

Four different data sets pertaining to the neutral atom environment at 1 AU are presented and discussed. These data sets include neutral solar wind and interstellar neutral atom data from IMAGE/LENA, energetic hydrogen atom data from SOHO/HSTOF and plasma wave data from the magnetometer on ISEE-3. Surprisingly, these data sets are centered between 262 degree

Mario Livio, J. E. Pringle, A. R. King

We propose a new model for the disk-jet connection in black hole x-ray transients and active galactic nuclei. In our model, the inner part of the accretion disk around the central black hole switches between two states. In one state, the accretion energy is dissipated locally (some within the disk, some within a corona) to produce the observed disk luminosit

L. Saul, E. Moebius, Y. Litvinenko, P. Isenberg

We present a recent analysis with 1996 SOHO CELIAS CTOF data, which reveals correlations of He+ pickup ion fluxes and spectra with the magnetic field strength and solar wind density. The motivation is to better understand the ubiquitous large variations in both pickup ion fluxes and their velocity distributions found in interstellar pickup ion datasets. We c

R. P. Kraft, S. Vazquez, W. R. Forman, C. Jones

We present results from two {\em Chandra}/ACIS-I observations and one {\em XMM-Newton} observation of X-ray emission from the ISM and the inner radio lobes of the nearby radio galaxy Centaurus A. The ISM has an average radial surface brightness profile that is well described by a $β$-model profile with index $β$=0.40$\pm$0.04 and a temperature of $k_BT_{ISM}

R. P. Kraft, W. R. Forman, E. Churazov, N. Laslo

We present results from a 45 ks Chandra/ACIS-I observation of the nearby ($z=0.01646$) NGC 507 group. The X-ray surface brightness profile of the outer region of the group is well described by an isothermal $β$-profile consistent with earlier ROSAT observations. We find a sharp edge or discontinuity in the radial surface brightness profile 55 kpc E and SE of

A. Bodaghee, N. C. Santos, G. Israelian, M. Mayor

In this paper, we present a study of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni in a large set of stars known to harbor giant planets, as well as in a comparison sample of stars not known to have any planet ary-mass companions. We have checked for possible chemical differences between planet hosts and field stars without known planets. Our resul

B. Mazur, W. Krzeminski, I. B. Thompson

We report on the discovery of eleven multimode SX Phoenicis--type blue stragglers in the field of the southern globular cluster NGC 3201. In these variables both radial and non-radial modes are excited. For three variables the derived period ratio is close to that observed in SX Phoenicis itself, suggesting that these stars are pulsating in the fundamental a

Garik Israelian, Nuno Santos, Michel Mayor, Rafael Rebolo

The presence of possible blends in the spectral region of the Li resonance line at 6708 A in solar-type metal-rich stars is investigated using high resolution and high signal-to-noise spectroscopic observations. Our analysis does not confirm the identification of a weak absorption feature at 6708.025 A with the low excitation TiI line proposed by Reddy et al

Cornelis de Jager, Garik Israelian

We report the detection of rapid wavelength and intensity variations of narrow components in absorption line profiles of the hot galactic supergiant P Cygni. During most of the time, in one week of observations, there were two such components present. Although the period of observation is too short for firm conclusions, the velocity curves do not contradict

Ravi K. Sheth

I develop a model for the abundance and spatial distribution of dark matter subclumps. The model shows that subclumps of massive parent halos formed at earlier times than subclumps of the same mass in lower mass parents; equivalently, halos in dense regions at a given time formed earlier than halos of the same mass in less dense regions. This may provide the

Harry J. Lipkin

Simple rigorous quantum mechanics with no hand waving nor loopholes clarifies the confusion between three contradictory descriptions of neutrino oscillations: (1)The time oscillations shown in standard textbooks produced by neutrino eigenstates with different masses and different energies. (2) That time oscillations and interference between states having dif

F. R. Klinkhamer, C. Rupp

The topology of configuration space may be responsible in part for the existence of sphalerons. Here, sphalerons are defined to be static but unstable finite-energy solutions of the classical field equations. Another manifestation of the nontrivial topology of configuration space is the phenomenon of spectral flow for the eigenvalues of the Dirac Hamiltonian

G. J. Pryde, A. G. White

We theoretically demonstrate a method for producing the maximally path-entangled state (1/Sqrt[2]) (|N,0> + exp[iN phi] |0,N>) using intensity-symmetric multiport beamsplitters, single photon inputs, and either photon-counting postselection or conditional measurement. The use of postselection enables successful implementation with non-unit efficiency detecto

M. O. Katanaev

We consider the Skyrme model using the explicit parameterization of the rotation group SO(3) through elements of its algebra. Topologically nontrivial solutions already arise even in the one-dimensional case because the fundamental group of SO(3) is Z_2. We explicitly find and analyze one-dimensional static solutions. Among them, there are topologically nont

Taekoon Lee

The heavy quark pole mass in perturbation theory suffers from a renormalon caused, inherent uncertainty of $O(Λ_{\rm QCD})$. This fundamental difficulty of determining the pole mass to an accuracy better than the inherent uncertainty can be overcome by direct resummation of the first infrared renormalon. We show how a properly defined pole mass as well as th

Darius Sadri, M. M. Sheikh-Jabbari

The most general parallelizable pp-wave backgrounds which are non-dilatonic solutions in the NS-NS sector of type IIA and IIB string theories are considered. We demonstrate that parallelizable pp-wave backgrounds are necessarily homogeneous plane-waves, and that a large class of homogeneous plane-waves are parallelizable, stating the necessary conditions. Su

John C. Hauck, Bahram Mashhoon

We discuss the electromagnetic measurements of rotating observers and study the propagation of electromagnetic waves in a uniformly rotating frame of reference. The phenomenon of helicity-rotation coupling is elucidated and some of the observational consequences of the coupling of the spin of a particle with the rotation of a gravitational source are briefly

F. Benamira, L. Guechi

We comment on several incorrect results given in a recent paper by Lo and Wong. In particular, it is pointed out that their evaluation of the propagator for two coupled general driven time-dependent oscillators is not satisfactory. The correct expression can be obtained by applying an appropriate time-dependent canonical transformation.

Han-Ying Guo, Jianzhong Pan, Ke Wu, Bin Zhou

The definition and properties of the Euler-Lagrange cohomology groups $H^{2k-1}$, $1 \leqslant k \leqslant n$, on a symplectic manifold $({\cal M}^{2n},ω)$ are given and studied. For $k = 1$ and $k = n$, they are isomorphic to the corresponding de Rham cohomology groups $H_{dR}^1({\cal M}^{2n})$ and $H_{dR}^{2n-1}({\cal M}^{2n})$, respectively. The other Eul

Kevin K. Lehmann

The density of states and other thermodynamic functions of helium nanodroplets are calculated for a microcanonical ensemble with both energy and total angular momentum treated as conserved quantum numbers. These functions allow angular momentum conserving evaporative cooling simulations. As part of this project, a recursion relationship is derived for the re

Y. E. Kim, J. -H. Yoon, R. A. Rice, M. Rabinowitz

Temperature and kinematic line broadening are the primary contributions to the width of the proton energy spectrum measured in cluster-impact fusion experiments. By ascertaining these two contributions, we have determined an effective temperature for the high-velocity deuteron component that is responsible for the measured fusion yield. The extracted effecti

D. R. Entem, R. Machleidt

In a recent study [M.C.M. Rentmeester et al., Phys. Rev. C 67, 044001 (2003)], the Nijmegen group reports on the determination of the chiral low-energy constants (LEC), c_3 and c_4, involved in the 2-pi-exchange part of the NN amplitude at next-to-next-to-leading order (NNLO) of chiral perturbation theory. This analysis does not apply the uniquely-determined

H. Susanto, T. P. P. Visser, S. A. van Gils

Dynamics of a fluxon in a stack of coupled long Josephson junctions is studied numerically. Based on the numerical simulations, we show that the dependence of the propagation velocity $c$ on the external bias current $γ$ is determined by the ratio of the critical currents of the two junctions $J$.

Alexei D. Miasnikov, Alexei G. Myasnikov

In this paper we discuss a genetic version (GWA) of the Whitehead&#39;s algorithm, which is one of the basic algorithms in combinatorial group theory. It turns out that GWA is surprisingly fast and outperforms the standard Whitehead&#39;s algorithm in free groups of rank >= 5. Experimenting with GWA we collected an interesting numerical data that clarifies t

Anatoly Vershik, Natalia Tsilevich

We explicitly construct and study an isometry between the spaces of square integrable functionals of an arbitrary Levy process and a vector-valued Gaussian white noise. In particular, we obtain explicit formulas for this isometry at the level of multiplicative functionals and at the level of orthogonal decompositions, as well as find its kernel. We consider

Daniel Henry Gottlieb

Given a parameterized space of square matrices, the associated set of eigenvectors forms some kind of a structure over the parameter space. When is that structure a vector bundle? When is there a vector field of eigenvectors? We answer those questions in terms of three obstructions, using a Homotopy Theory approach. We illustrate our obstructions with five e

John Lott

The Bakry-Emery tensor gives an analog of the Ricci tensor for a Riemannian manifold with a smooth measure. We show that some of the topological consequences of having a positive or nonnegative Ricci tensor are also valid for the Bakry-Emery tensor. We show that the Bakry-Emery tensor is nondecreasing under a Riemannian submersion whose fiber transport prese

L. Mesref

We introduce a new map between a q-deformed gauge theory on a general GL_{q}(N)-covariant quantum hyperplane and an ordinary gauge theory in a full analogy with Seiberg-Witten map. Perturbative analysis of the q-deformed QED at the classical level is presented and gauge fixing a la BRST is discussed

M. de Campos

We study tensorial perturbations (gravitational waves) in a universe with particle production (OSC). The background of gravitational waves produces a perturbation in the redshift observed from distant sources. The modes for the perturbation in the redshift (induced redshift) are calculated in a universe with particle production.

Jose M. Martin-Garcia, Carsten Gundlach

At the threshold of black hole formation in the gravitational collapse of a scalar field a naked singularity is formed through a universal critical solution that is discretely self-similar. We study the global spacetime structure of this solution. It is spherically symmetric, discretely self-similar, regular at the center to the past of the singularity, and

R. Fantoni, G. Pastore

We discuss and illustrate through numerical examples the relations between generating functionals, thermodynamic consistency (in particular the virial-free energy one), and uniqueness of the solution, in the integral equation theory of liquids. We propose a new approach for deriving closures automatically satisfying such characteristics. Results from a first

S. A. Pavluchenko

We have investigated the generality of inflation (the probability of inflation in other words) in closed FRW models for a wide class of quintessence potentials. It is shown that inflation is not suppressed for most of them and for a wide enough range of their parameters. It allows us to decide inflation is common enough even in the case of closed Universe.