February 2002 arXiv papers — page 4

Jean-Paul Jurzak

In this paper, we show that Riemann hypothesis (concerning zeros of the zeta function in the critical strip) is equivalent to the analytic continuation of Euler products obtained by restricting the Euler zeta product to suitable subsets $M_k$, $k\geq 1$ of the set of prime numbers. Each of these Euler product defines so a partial zeta function $ζ_{k}(s)$ equ

Stephane Baseilhac

Let $\mathcal{W}_N$ be a quantized Borel subalgebra of $U_q(sl(2,\mc))$, specialized at a primitive root of unity $ω= \exp(2iπ/N)$ of odd order $N >1$. One shows that the $6j$-symbols of cyclic representations of $\mathcal{W}_N$ are representations of the canonical element of a certain extension of the Heisenberg double of $\mathcal{W}_N$. This canonical ele

Giuseppe Dito

After sketching recent advances and subtleties in classical relativistically covariant field theories, we give in this short Note some indications as to how the deformation quantization approach can be used to solve or at least give a better understanding of their quantization.

Jean-Paul Jurzak

In this paper, we study the holomorphic function defined by the infinite product $Γ_{a,r}(s) =\prod_{n \geq 0} (1 + \frac{1}{a+ nr})^s (1 + \frac{s}{a+nr})^{-1}$ which generalize Euler's definition in the sense that $Γ(s) = \frac{Γ_{1,1}(s)}{s}$. We obtain analogues of the Gauss multiplication formula, complement formula for functions $Γ_{a,r}(s)$.

Satyabrata Adhikari, Abhijit Sen

An extension to the factorisation principle as suggested by Fermat is presented.We start from a symmetry of natural numbers and obtain the factorisation principle therefrom.Later it is extended further to test the primality of any natural number and finally used to factorise any given number.

Masaki Kashiwara

We shall give various realizations of crystals. One of them is a monome realization introduced by Nakajima.

Wei-Ping Li, Zhenbo Qin, Weiqiang Wang

We construct geometrically the generating fields of a W algebra which acts irreducibly on the direct sum of the cohomology rings of the Hilbert schemes of n points on a projective surface for all n. We compute explicitly the commutators among a set of linear basis elements of the W algebra, and identify this algebra with a $W_{1+\infty}$-type algebra. A prec

Vestislav Apostolov, John Armstrong, Tedi Draghici

We classify, up to a local isometry, all non-Kahler almost Kahler 4-manifolds for which the fundamental 2-form is an eigenform of the Weyl tensor, and whose Ricci tensor is invariant with respect to the almost complex structure. Equivalently, such almost Kahler 4-manifolds satisfy the third curvature condition of A. Gray. We use our local classification to s

Peter A. Hasto

The M-relative distance, denoted by ρ_M is a generalization of the p-relative distance, which was introduced by Ren-Cang Li. We establish necessary and sufficient conditions under which ρ_M is a metric. In two special cases we derive complete characterizations of the metric. We also present a way of extending the results to metrics sensitive to the domain in

Itai Benjamini, Elchanan Mossel

We study the robustness under perturbations of mixing times, by studying mixing times of random walks in percolation clusters inside boxes in $\Z^d$. We show that for $d \geq 2$ and $p > p_c(\Z^d)$, the mixing time of simple random walk on the largest cluster inside $\{-n,...,n\}^d$ is $Θ(n^2)$ - thus the mixing time is robust up to constant factor.

A. A'Campo-Neuen, J. Hausen

We consider subtorus actions on divisorial toric varieties. Here divisoriality means that the variety has many Cartier divisors like quasiprojective and smooth ones. We characterize when a subtorus action on such a toric variety admits a categorical quotient in the category of divisorial varieties. Our result generalizes previous statements for the quasiproj

Pierre van Baal

We present an exact normalisable zero-energy chiral fermion solution for abelian BPS dipoles. For a single dipole, this solution is contained within the high temperature limit of the SU(2) caloron with non-trivial holonomy.

M. C. Diamantini, C. A. Trugenberger

We show that, contrary to previous string models, the high-temperature behaviour of the recently proposed confining strings reproduces exactly the correct large-N QCD result, a {\it necessary} condition for any string model of confinement.

V. V. Dyadichev, D. V. Gal'tsov

Regular magnetic monopoles in the non-Abelian Born-Infeld-Higgs theory are known to exist in the region of the field strength parameter $β>β_{\rm cr}$, bounded from below. Beyond this region, only pointlike (embedded abelian) monopoles exist, and we show that the transition from the regular to singular structure is reminiscent of gravitational collapse. Near

Somdatta Bhattacharya

In hep-th/9803002, Maldacena argued that in the light of the AdS/CFT correspondence as formulated by Witten and Gubser, Klebanov and Polyakov as a relation between partition functions, the expectation value of the Wilson loop in $\cal N$=4 SU(N) SYM is given by the worldsheet partition function with the action formulated on an $AdS_5\times S^5$ background an

Ning Wu

The quantum gravity is formulated based on principle of local gauge invariance. The model discussed in this paper has local gravitational gauge symmetry and gravitational field is represented by gauge field. In leading order approximation, it gives out classical Newton's theory of gravity. It can also give out Einstein's field equation with cosmologi

Kenneth Lane

These two lectures on technicolor and extended technicolor (ETC) were presented at l'Ecole de GIF at LAPP, Annecy-le-Vieux, France, in September 2001. In Lecture I, the motivation and structure of this theory of dynamical breaking of electroweak and flavor symmetries is summarized. The main phenomenological obstacles to this picture--flavor-changing neut

Mark Byrne, Christopher Kolda, Peter Regan

Supersymmetric models often predict a lightest superpartner (LSP) which is electrically charged and stable on the timescales of collider experiments. If such a particle were to be observed experimentally, is it possible to determine whether or not it is stable on cosmological timescales? Charged, stable particles are usually considered to be excluded by cosm

Kh. M. Beshtoev

The elements of the theory of dynamical expansion of the theory of weak interaction working at the tree level, i.e. the model of dynamical analogy of Cabibbo-Kobayashi- Maskawa matrices, are given. The equation for mass difference of $K^0_1, K^0_2$ mesons or the length of $K^0, \bar K^0$ meson oscillations in the phase volume approach in the frame work of th

L. Micu

We show that a bound system in momentum space can be treated like a gas of free elementary constituents and a collective excitation of a background field which represents the countless quantum fluctuations generating the binding potential. The distribution function of the internal momenta in the bound system at rest is given by the projection of the solution

Saurabh D. Rindani

QCD corrections to order alpha_s in the soft-gluon approximation to angular distributions of decay charged leptons in the process e+e- -> t tbar followed by semileptonic decay of t or tbar, are obtained in the e+e- centre-of-mass frame. As compared to distributions in the top rest frame, these have the advantage that they would allow direct comparison with e

S. V. Molodtsov, G. M. Zinovjev

We study light quark interactions in the instanton liquid at finite quark/baryon number density analyzing chiral and diquark condensates and investigate the behaviors of quark dynamical mass and both condensates together with instanton liquid density as a function of quark chemical potential. We conclude the quark impact (estimated in the tadpole approximati

G. Bergqvist, A. Hoglund

The classical Rainich(-Misner-Wheeler) theory gives necessary and sufficient conditions on an energy-momentum tensor $T$ to be that of a Maxwell field (a 2-form) in four dimensions. Via Einstein's equations these conditions can be expressed in terms of the Ricci tensor, thus providing conditions on a spacetime geometry for it to be an Einstein-Maxwell sp

M. Govender

We present here a simple model of radiative gravitational collapse with radial heat flux which describes qualitatively the stages close to the formation of a superdense cold star. Starting with a static general solution for a cold star, the model can generate solutions for the earlier evolutionary stages. The temporal evolution of the model is specified by s

Wolfram Schmidt

The dynamical parameters conventionally used to specify the orbit of a test particle in Kerr spacetime are the energy $E$, the axial component of the angular momentum, $L_{z}$, and Carter's constant $Q$. These parameters are obtained by solving the Hamilton-Jacobi equation for the dynamical problem of geodesic motion. Employing the action-angle variable

Leszczynski Jacek, Pluta Sebastian

Many problems in engineering, chemistry and physics require the representation of solutions in complex geometries. In the paper we deal with a problem of unstructured mesh generation for the control volume method. We propose an algorithm which bases on the spheres generation in central points of the control volumes.

Andrei N. Soklakov

Given a reference computer, Kolmogorov complexity is a well defined function on all binary strings. In the standard approach, however, only the asymptotic properties of such functions are considered because they do not depend on the reference computer. We argue that this approach can be more useful if it is refined to include an important practical case of s

T. Schauerte, P. G. J. van Dongen

The phase diagram of the Hubbard model is studied at weak coupling in two and three spatial dimensions. It is shown that the Neel temperature and the order parameter in d=3 are smaller than the Hartree-Fock predictions by a factor of q=0.2599. For d=2 we show that the self-consistent (sc) perturbation series bears no relevance to the behavior of the exact so

P. S. Cornaglia, C. A. Balseiro

We present results for Kondo impurities in nanoscopic systems. Using exact diagonalization in small clusters and Wilson's renormalization group we analyze an isolated system and a nanoscopic system weakly coupled to a macroscopic reservoir. In the latter case, new regimes not observed in macroscopic homogeneous systems are induced by the confinement of c

Gang Lu, Vasily V. Bulatov, Nicholas Kioussis

A novel model based on the Peierls framework of dislocations is developed. The new theory can deal with a dislocation spreading at more than one slip planes. As an example, we study dislocation cross-slip and constriction process of two fcc metals, Al and Ag. The energetic parameters entering the model are determined from ab initio calculations. We find that

I. M. Yurin, V. B. Kalinin

In this work, a question is tackled concerning the formation of a superconducting condensate in an earlier proposed model of "elastic jelly", in which phonons of the ion system play the part of initiating ones. It was shown that in distinction from the BCS theory, the momenta of forming electron pairs are different from zero. This fact changes the pa

L. Trujillo, H. J. Herrmann

We present a hydrodynamic theoretical model for "Brazil nut" size segregation in granular materials. We give analytical solutions for the rise velocity of a large intruder particle immersed in a medium of monodisperse fluidized small particles. We propose a new mechanism for this particle size-segregation due to buoyant forces caused by density varia

N. E. Zein, V. P. Antropov

We present an approach for self-consistent calculations of the many-body Green function in transition metals. The distinguishing feature of our approach is the use of the one-site approximation and the self-consistent quasiparticle wave function basis set, obtained from the solution of the Schrodinger equation with a nonlocal potential. We analyze several se

T. Schulte, L. Santos, A. Sanpera, M. Lewenstein

We analyze the vortex dynamics and vortex-vortex interactions in Bose-Einstein condensates confined in toroidal traps. We show that this particular geometry strongly distorts the vortex dynamics. The numerically calculated vortex trajectories are well explained by an analytical calculation based on image method and conformal mapping. Finally, the dissipation

A. O. Govorov, C. Schulhauser, D. Haft, A. V. Kalameitsev

We present both experimental and theoretical results on the influence of a magnetic field on excitons in semiconductor quantum dots. We find a pronounced difference between the strong and weak confinement regimes. For weak confinement, the excitonic diamagnetic shift is strongly dependent on surplus charge, corresponding to a reversal in sign of the conventi

Matteo Marsili, Maurizio Piai

We study the behavior of simple models for financial markets with widely spread frequency either in the trading activity of agents or in the occurrence of basic events. The generic picture of a phase transition between information efficient and inefficient markets still persists even when agents trade on widely spread time-scales. We derive analytically the

Saurabh Basu, A. Callan-Jones, R. J. Gooding

We have studied the enhancement of the superconducting transition temperature, Tc, in a t-J-U model of electrons moving on a square lattice in which anisotropic electronic hopping is introduced. The inclusion of such hopping mimics, in a approximate fashion, a potentially important characteristic of materials possessing stripelike charge and spin correlation

Achod Aradian, Elie Raphael, Pierre-Gilles de Gennes

We study theoretically situations where competition arises between an interdiffusion process and a cross-linking chemical reaction at interfaces between pieces of the same polymer material. An example of such a situation is observable in the formation of latex films, where, in the presence of a cross-linking additive, colloidal polymer particles initially in

Edward McCann, Vladimir I. Fal'ko

We present a model of the thermopower in a mesoscopic tunnel junction between two ferromagnetic metals based upon magnon-assisted tunneling processes. In our model, the thermopower is generated in the course of thermal equilibration between two baths of magnons, mediated by electrons. We predict a particularly large thermopower effect in the case of a juncti

V. I. Anisimov, R. Hlubina, M. A. Korotin, V. V. Mazurenko

The contrasting groundstates of isoelectronic and isostructural FeSi and FeGe can be explained within an extended local density approximation scheme (LDA+U) by an appropriate choice of the onsite Coulomb repulsion, $U$ on the Fe-sites. A minimal two-band model with interband interactions allows us to obtain a phase diagram for the alloys FeSi$_{1-x}$Ge$_{x}$

A. Awazu

History-dependent maximum static friction is investigated using simple models with two and three particles in one-dimensional periodic potentials. In some situations, these systems possess two values of the maximum static friction, with that actually realized being determined by the direction of the slippage relative to the direction of the previous slippage

S. A. Tarasenko, E. L. Ivchenko

The theory of spin orientation of two-dimensional (2D) electron gas has been developed for intrasubband indirect optical transitions. The monopolar optical orientation of electrons in the conduction band is caused by the indirect scattering with virtual intermediate states in the valence band and allowance for selection rules for interband transitions. The c

P. Patricio, M. M. Telo da Gama, S. Dietrich

We study geometrically-controlled twist transitions of a nematic confined between a sinusoidal grating and a flat substrate. In these cells the transition to the twisted state is driven by surface effects. We have identified the mechanisms responsible for the transition analytically and used exact numerical calculations to study the range of surface paramete

Tatyana. I. Baturina, D. R. Islamov, Z. D. Kvon

We present the results of low-temperature transport measurements on chains of superconductor--normal-constriction--superconductor (SNS) junctions fabricated on the basis of superconducting PtSi film. A comparative study of the properties of the chains, consisting of 3 and 20 SNS junctions in series, and single SNS junctions reveals essential distinctions in

S. Cocco, R. Monasson, J. Marko

A theory of the unzipping of double-stranded (ds) DNA is presented, and is compared to recent micromanipulation experiments. It is shown that the interactions which stabilize the double helix and the elastic rigidity of single strands (ss) simply determine the sequence dependent =12 pN force threshold for DNA strand separation. Using a semi-microscopic model

J. Balogh, M. Csontos, D. Kaptas, G. Mihaly

Giant magnetoresistance (GMR) of sequentially evaporated Fe-Ag structures have been investigated. Direct experimental evidence is given that inserting ferromagnetic layers into a granular structure significantly enhances the magnetoresistance. The increase of the GMR effect is attributed to spin polarization effects. The large enhancement (up to more than a

Gyorgy Szabo, Hajnalka Gergely, Beata Oborny

Spreading from a seed is studied by Monte Carlo simulation on a square lattice with two types of sites affecting the rates of birth and death. These systems exhibit a critical transition between survival and extinction. For time- dependent background, this transition is equivalent to those found in homogeneous systems (i.e. to directed percolation). For froz

Hermann Grabert, Gert-Ludwig Ingold

The effects of Macroscopic Quantum Tunneling (MQT) and Coulomb Blockade (CB) in Josephson junctions are of considerable significance both for the manifestations of quantum mechanics on the macroscopic scale and potential technological applications. These two complementary effects are shown to be clearly distinguishable from the associated noise spectra. The

Keshav N. Shrivastava

We have examined the claim made by Kukushkin et al that they have observed the cyclotron resonance of composite fermions. We find that the claim made is false and there is no justification for making false reports. The microwave absorption in cyclotron levels is observed and it is claimed that CF has been seen. Since "even flux quanta attachment to one e

J. P. Huang, K. W. Yu

We have investigated the effect of particle shape on the eletrorotation (ER) spectrum of living cells suspensions. In particular, we consider coated oblate spheroidal particles and present a theoretical study of ER based on the spectral representation theory. Analytic expressions for the characteristic frequency as well as the dispersion strength can be obta

J. S. Ahn, E. S. Choi, W. Kang, D. J. Singh

We investigated thermoelectric power $S(T)$ of MgB$_{2-x}$Be$_{x}$ ($x=0$, 0.2, 0.3, 0.4, and 0.6). $S(T)$ decreases systematically with $x$, suggesting that the hole density increases. Our band calculation shows that the increase occurs in the $σ$-band. With the hole-doping, $T_{c}$ decreases. Implication of this phenomenon is discussed within the BCS frame

Dmitry Green

This thesis is a theoretical analysis of sample two- and one-dimensional systems. The two-dimensional examples are the quantum Hall liquid and anomalous paired states. The most widely accepted effective theory of the quantum Hall liquid is based on the so-called Chern Simons Lagrangian, but it is not entirely satisfactory. We obtain the first derivation of a

G. Pietrzy{ń}ski, W. Gieren, P. Fouque, F. Pont

Based on observations of NGC 300, obtained with the Wide-Field Camera at the 2.2 m ESO/MPI telescope during 29 nights spread over a 5.3 month interval, 117 Cepheids and 12 Cepheid candidates were found which cover the period range from 115 to 5.4 days. We present a catalog which provides equatorial coordinates, period, time of maximum brightness, and intensi

D. M. Alexander, H. Aussel, F. E. Bauer, W. N. Brandt

Using the 1 Ms Chandra Deep Field North and 15 micron ISOCAM HDF-N surveys we find a tight correlation between the population of strongly evolving starbursts discovered in faint 15 micron ISOCAM surveys and the apparently normal galaxy population detected in deep X-ray surveys. Up to 100% of the X-ray detected emission-line galaxies (ELGs) have 15 micron cou

Juan C. Forte, Lilia P. Bassino, E. Irene Vega, Leonardo J. Pellizza Gonzalez

We present linear polarization in the V band for 77 stars in the field of the globular cluster 47 Tucanae (NGC 104), and for 14 bright-star-free regions, located along an elliptical isophotal contour of the cluster, as well as UBVRI measurements for the cluster nucleus. The observations show variable foreground polarization that, once removed, leaves margina

D. W. A. Harvey, D. J. Wilner, J. Di Francesco, C. -W. Lee

We used the NRAO Very Large Array to search for 3.6 cm continuum emission from embedded protostars in a sample of 8 nearby ``starless'' cores that show spectroscopic evidence for infalling motions in molecular emission lines. We detect a total of 13 compact sources in the eight observed fields to 5 sigma limiting flux levels of typically 0.09 mJy. No

Manfred W. Pakull, Laurent Mirioni

Despite much observational and theoretical effort little is presently known about the nature of the luminous non-nuclear X-ray sources which appear to largely surpass the Eddington limit of a few solar masses. Here we present first results of our OHP/ESO/CFHT optical survey of the environments of variable ultraluminous X-ray sources (ULX) in nearby galaxies.

Parviz Ghavamian, P. Frank Winkler, John C. Raymond, Knox S. Long

We present the deepest optical spectrum acquired to date of Balmer-dominated shocks in the NW rim of SN 1006. We detect the broad and narrow components of H-alpha, H-beta and H-gamma and report the first detection of the He I 6678 emission line in this supernova remnant. We may have detected, at the 1.5-sigma level, faint He II 4686 emission. We measure a fu

Masahiro Kawasaki, Masanobu Ozaki, Fumiaki Nagase, Kuniaki Masai

We present the results of X-ray spatial and spectral studies of the ``mixed-morphology'' supernova remnant IC 443 using ASCA. IC 443 has a center-filled image in X-ray band, contrasting with the shell-like appearance in radio and optical bands. The overall X-ray emission is thermal, not from a synchrotron nebula. ASCA observed IC 443 three times, cov

F. Ghinassi, J. Licandro, E. Oliva, C. Baffa

We report transmission measurements at cryogenic temperatures for 4 broad-band filters of the Mauna Kea Observatories (MKO) near-infrared filter set and 5 narrow-band filters. The spectral scans were collected using the multi-mode IR instrument of the TNG telescope (NICS) in which these filters are permanently mounted and commonly used for astronomical obser

Rafal M. Nowakowski

A nonlinear development of radial pulsation instability to a resonant excitation of nonradial modes is studied. The theory covers the cases of axisymmetric (m=0) modes as well as (m,-m) pairs. Adopting a simplified treatment of the mode coupling, it is found that multimode pulsation with constant amplitudes is a highly probable solution. An observable conseq

J. S. Kaastra, K. C. Steenbrugge, A. J. J. Raassen, R. L. J. van der Meer

We analyze the high-resolution X-ray spectrum of the Seyfert 1 galaxy NGC 5548, for the full 0.1-10 keV band, using improved calibration results of the Chandra-LETGS instrument. The warm absorber consists of at least three ionization components, namely one with a low, medium and high ionization parameter. The X-ray absorbing material, from an outflowing wind

A. De Luca, S. Molendi

We present a work in progress aimed at measuring the spectrum of the Cosmic X-ray Background (CXB) with the EPIC detectors onboard XMM-Newton. Our study includes a detailed characterization of the EPIC non X-ray background, which is crucial in making a robust measurement of the spectrum of CXB. We present preliminary results, based on the analysis of a set o

P. A. Caraveo, A. De Luca, N. La Palombara, R. Mignani

The limited angular resolution of gamma-ray telescopes prevents the straight identification of the majority of the sources detected so far. While the only certified galactic gamma-ray emitters are associated with pulsars, more than 90% of the nearly 100 low latitude sources detected by EGRET on the GRO lack an identification. The best identification strategy

P. Eggenberger, G. Meynet, A. Maeder

We present new determinations of the blue to red supergiant ratio ($B/R$) in young open clusters at various metallicities. For this purpose, we examine the HR diagrams of 45 clusters in the Galaxy and of 4 clusters in the Magellanic Clouds. The identification of supergiants is based on spectroscopic measurements (with photometric counts to check the results)

T. Lebzelter, K. H. Hinkle

We discuss velocity variations in different layers of an AGB star's atmosphere. Periodic and nonperiodic changes are observed. From a large sample of data we derive mean velocity curves for miras and semiregular variables.

Philippe Amram, Olivia Garrido

This survey, once completed, will provide a 3D sample of 200 nearby spiral and irregular galaxies in the Halpha line, using a Fabry-Perot system. The data cubes obtained for each galaxy allow derivation of lines maps, velocity fields and higher momentum. The goals of this survey are: (1) To constitute a 3D local reference. (2) To constrain the mass distribut

Valentin Buat-Menard, Jean-Marie Hameury

We include the tidal instability due to the 3:1 resonance in the disc instability model developed by Hameury et al. (1998) and modified by Buat-Menard et al. (2001). We confirm earlier results by Osaki (1989) that the tidal instability can account for the SU UMa light curves. We show that in ultra-low mass ratio systems such as ER UMa stars and WZ Sge stars,

Daniel E. Reichart, Paul A. Price

First, we show that the gamma-ray bursts with dark optical afterglows (DOAs) cannot be explained by a failure to image deeply enough quickly enough, and argue that circumburst extinction is the most likely solution. If so, many DOAs will be ``revived'' with rapid follow up and NIR searches in the HETE-2 and Swift eras. Next, we consider the effects o

H. Kjeldsen, T. R. Bedding, I. K. Baldry, S. Frandsen

We report observations of the G0 subgiant eta Boo made in 1998, in Balmer-line equivalent width with the 2.5-m Nordic Optical Telescope and in velocity with the 24-inch Lick CAT. In both data sets we see an excess in the power spectrum, with oscillation frequencies that confirm the earlier observations by Kjeldsen et al. (1995).

T. R. Bedding, H. Kjeldsen, I. K. Baldry, F. Bouchy

Velocity measurements of the G2 subgiant beta Hyi with both UCLES and CORALIE show a clear excess of power centred at 1.0 mHz. In the UCLES data we find evidence for a short-lived, high-amplitude oscillation event. If confirmed as a feature of subgiants, such `starquakes' would make it harder to measure accurate mode frequencies and perform asteroseismol

Z. K. Silagadze

This talk was given at the Tunguska-2001 international conference but it is not about the Tunguska event. Instead we tried to give some flavor of mirror matter, which is predicted to exist if parity is an unbroken symmetry of nature, to non-experts. The possible connection of the mirror matter ideas to the Tunguska phenomenon was indicated by Foot and Gninen

Jeong-Man Park, Michael W. Deem

A new statistical field-theory model of isotropic turbulence is introduced. The model renormalizes the effects of turbulent stresses into a velocity-gradient-dependent random force. The model is well-defined within the context of the renormalization group $ε$ expansion, as the effective expansion parameter is $O(ε)$. The Kolmogorov constant and $N$ parameter

Sacha Davidson, Alejandro Ibarra

In the seesaw model, the baryon asymmetry of the Universe can be generated by the decay of the lightest right-handed neutrino, nu_R. For a hierarchical spectrum of right-handed neutrinos, we show that there is a model independent upper bound on the CP asymmetry produced in these decays: epsilon < 3 m_{nu_3} M_{nu_R}/(8 pi <H_u>^2). This implies that epsilon

V. Del Duca, F. Maltoni, Z. Trocsanyi

In the analysis of the total cross section for the gamma* gamma* -> hadrons process, we include the four parton final states, which are part of the O(alpha_s^2) corrections. The four-parton final states contain the diagrams with gluon exchange in the crossed channel, which constitute the leading order of the BFKL resummation. We show that the diagrams with g

Deog Ki Hong, Stephen D. H. Hsu

We show that the effective field theory of low energy modes in dense QCD has positive Euclidean path integral measure. The complexity of the measure of QCD at finite chemical potential can be ascribed to modes which are irrelevant to the dynamics at sufficiently high density. Rigorous inequalities follow at asymptotic density. Lattice simulation of dense QCD

Qimiao Si, Silvio Rabello, Kevin Ingersent, Lleweilun Smith

We show that spatially local, yet low-energy, fluctuations can play an essential role in the physics of strongly correlated electron systems tuned to a quantum critical point. A detailed microscopic analysis of the Kondo lattice model is carried out within an extended dynamical mean-field approach. The correlation functions for the lattice model are calculat

Gia Dvali, Gregory Gabadadze, M. Shifman

We argue that the cosmological constant problem can be solved in a braneworld model with infinite-volume extra dimensions, avoiding no-go arguments applicable to theories that are four-dimensional in the infrared. Gravity on the brane becomes higher-dimensional at super-Hubble distances, which entails that the relation between the acceleration rate and vacuu

Y. Alhassid, S. Malhotra

We use a Hartree-Fock-Koopmans approach to study spin and interaction effects in a diffusive or chaotic quantum dot. In particular, we derive the statistics of the spacings between successive Coulomb-blockade peaks. We include fluctuations of the matrix elements of the two-body screened interaction, surface-charge potential, and confining potential to leadin

Steven Detweiler, Bernard F. Whiting

The gravitational field of a particle of small mass μmoving through curved spacetime is naturally decomposed into two parts each of which satisfies the perturbed Einstein equations through O(μ). One part is an inhomogeneous field which, near the particle, looks like the μ/r field distorted by the local Riemann tensor; it does not depend on the behavior of th

D. Minic, C. H. Tze

We propose a generalization of the standard geometric formulation of quantum mechanics, based on the classical Nambu dynamics of free Euler tops. This extended quantum mechanics has in lieu of the standard exponential time evolution, a nonlinear temporal evolution given by Jacobi elliptic functions. In the limit where latter&#39;s moduli parameters are set t

S. Gupta, K. Dieckmann, Z. Hadzibabic, D. E. Pritchard

The kinetic energy of an atom recoiling due to absorption of a photon was measured as a frequency using an interferometric technique called ``contrast interferometry&#39;&#39;. Optical standing wave pulses were used as atom-optical elements to create a symmetric three-path interferometer with a Bose-Einstein condensate. The recoil phase accumulated in differ

Richard Lieu

The starting point of this work is the axiomatic existence of a smallest measurable interval, viz. the Planck time $t_P$, set by quantum fluctuations in the vacuum metric tensor. By the Relativity Principle, the same limit must then apply to the accuracy of all clocks which register time of events in their own frames. Further, it implies that the ordinary me

A. Marshakov, A. Yung

We study confinement in softly broken N=2 SUSY QCD with gauge group SU(N_c) and N_f hypermultiplets of fundamental matter (quarks) when the Coulomb branch is lifted by small mass of adjoint matter. Concentrating mostly on the theory with SU(3) gauge group we discuss the N=1 vacua which arise in the weak coupling at large values of quark masses and study flux

C. D&#39;Helon, V. Protopopescu

We propose an ensemble algorithm, which provides a new approach for evaluating and summing up a set of function samples. The proposed algorithm is not a quantum algorithm, insofar it does not involve quantum entanglement. The query complexity of the algorithm depends only on the scaling of the measurement sensitivity with the number of distinct spin sub-ense

V. Protopopescu, R. Perez, C. D&#39;Helon, J. Schmulen

We present an open loop (bang-bang) scheme to control decoherence in a generic one-qubit quantum gate and implement it in a realistic simulation. The system is consistently described within the spin-boson model, with interactions accounting for both adiabatic and thermal decoherence. The external control is included from the beginning in the Hamiltonian as a

Jan Van den Bussche, Stijn Vansummeren, Gottfried Vossen

We describe a meta-querying system for databases containing queries in addition to ordinary data. In the context of such databases, a meta-query is a query about queries. Representing stored queries in XML, and using the standard XML manipulation language XSLT as a sublanguage, we show that just a few features need to be added to SQL to turn it into a fully-

Kelle L. Cruz, I. Neill Reid

We present initial results of an all-sky search for late-type dwarfs within 20 pc of the Sun using the New Luyten Two-Tenths (NLTT) catalog cross-referenced with the 2-Micron All Sky Survey (2MASS) database. The results were obtained with low-resolution optical spectroscopic follow-up of candidate nearby-stars as a preliminary test of our methodology. M_J, d

Ph. Hägler, B. Pire, L. Szymanowski, O. V. Teryaev

Charge asymmetries in diffractive electroproduction of two mesons are proportional to the interference of Pomeron and Odderon exchange amplitudes. We calculate in the framework of QCD and in the Born approximation a forward-backward charge asymmetry which turns out to be sizable in a kinematical domain accessible to HERA experiments. We predict a distinctive

Roderich Tumulka

Horton, Dewdney, and Nesteruk [quant-ph/0103114] have proposed Bohm-type particle trajectories accompanying a Klein-Gordon wave function psi on Minkowski space. From two vector fields on space-time, W^+ and W^-, defined in terms of psi, they intend to construct a timelike vector field W, the integral curves of which are the possible trajectories, by the foll

Pavel Etingof, Shlomo Gelaki

We explain that a new theorem of Deligne on symmetric tensor categories implies, in a straightforward manner, that any finite dimensional triangular Hopf algebra over an algebraically closed field of characteristic zero has Chevalley property, and in particular the list of finite dimensional triangular Hopf algebras over such a field given in math.QA/0008232

S. Udry, M. Mayor, D. Naef, F. Pepe

Doppler CORALIE measurements of the solar-type stars HD141937, HD162020, HD168443 and HD202206 show Keplerian radial-velocity variations revealing the presence of 4 new companions with minimum masses close to the planet/brown-dwarf transition, namely with m_2sin(i) = 9.7, 14.4, 16.9, and 17.5 M_Jup, respectively. The orbits present fairly large eccentricitie

F. Pepe, M. Mayor, F. Galland, D. Naef

We present the discovery of two Saturn-mass companions to HD108147 and HD168746. Both belong to the lightest ever discovered planets. The minimum mass of the companion to HD168746 is of only 0.77 the mass of Saturn and its orbital period is 6.4 days. The companion to HD108147 orbits its parent star in 10.9 days and its minimum mass is 1.34 that of Saturn. It

Marek Karliner, Shmuel Nussinov

We discuss the QCD constraints on e+e- --> baryon-anti-baryon close to threshold, in light of the puzzling experimental data which indicate that close to threshold sigma (e+e- --> n n-bar) > sigma (e+e- --> p p-bar). We focus on the process e+e- --> Delta Delta-bar, which is particularly simple from the theoretical point of view. In this case it is possible

T. Asakawa, S. Sugimoto, S. Terashima

We analyse unstable D-brane systems in type I string theory. Generalizing the proposal in hep-th/0108085, we give a physical interpretation for real KK-theory and claim that the D-branes embedded in a product space X x Y which are made from the unstable Dp-brane system wrapped on Y are classified by a real KK-theory group KKO^{p-1}(X,Y). The field contents o

Jose L. Cereceda

The notions of three-particle entanglement and three-particle nonlocality are discussed in the light of Svetlichny&#39;s inequality [Phys. Rev. D 35, 3066 (1987)]. It is shown that there exist sets of measurements which can be used to prove three-particle entanglement, but which are nevertheless useless at proving three-particle nonlocality. In particular, i

O. Parcollet, C. Hooley

This paper is concerned with the out-of-equilibrium two-lead Kondo model, considered as a model of a quantum dot in the Kondo regime. We revisit the perturbative expansion of the dot&#39;s magnetization, and conclude that, even at order 0 in the Kondo interactions, the magnetization is not given by the usual equilibrium result. We use the Schwinger-Keldysh m

Swarnendu Sarkar

UV/IR mixing is one of the most important features of noncommutative field theories. As a consequence of this coupling of the UV and IR sectors, the configuration of fields at the zero momentum limit in these theories is a very singular configuration. We show that the renormalization conditions set at a particular momentum configuration with a fixed number o

M. Novello, J. Barcelos-Neto, J. M. Salim

We use a model where the cosmological term can be related to the chiral gauge anomaly of a possible quantum scenario of the initial evolution of the universe. We show that this term is compatible with the Friedmann behavior of the present universe.

P. Devillard, R. Guyon, T. Martin, I. Safi

Andreev reflection between a normal metal and a superconductor whose order parameter exhibits quantum phase fluctuations is examined. The approach chosen is non perturbative in the tunneling Hamiltonian and enables to probe the whole range of voltage biases up to the gap amplitude. Results are illustrated using the one-dimensional Josephson- Junction Array m