November 2001 arXiv papers — page 4
Showing 301–400 of 3,154 papers
Shape of nanosize superconducting grains: Does it influence pairing characteristics?
cond-mat.supr-conV. N. Gladilin, V. M. Fomin, J. T. Devreese
The Richardson exact solution for the reduced BCS Hamiltonian is applied to examine how sensitive are the pairing characteristics (condensation energy, spectroscopic gap, parity gap) to a specific configuration of single-electron energy levels in nanosize metallic grains. Using single-electron energy spectra in parallelepiped-shaped potential boxes with vari
Arturo Kohatsu-Higa, Miquel Montero
In this article, we give a brief informal introduction to Malliavin Calculus for newcomers. We apply these ideas to the simulation of Greeks in Finance. First to European-type options where formulas can be computed explicitly and therefore can serve as testing ground. Later we study the case of Asian options where close formulas are not available. The Greeks
D. Guery-Odelin
In this article, we investigate mean field effects for a bosonic gas harmonically trapped above the transition temperature in the collisionless regime. We point out that those effects can play also a role in low dimensional system. Our treatment relies on the Boltzmann equation with the inclusion of the mean field term. The equilibrium state is first discuss
Theory of Incoherent Nuclear Inelastic Resonant Scattering of Synchrotron Radiation
cond-mat.mtrl-sciV. G. Kohn, A. I. Chumakov
The theory of incoherent nuclear resonant scattering of synchrotron radiation accompanied by absorption or emission of phonons in a crystal lattice is developed. The theory is based on the Maxwell's equations and time-dependent quantum mechanics under the condition of incoherent scattering of radiation by various nuclei. A concept of coherence in scatter
A. Montina, E. Arimondo
In this article we introduce a differential equation for the first order correlation function $G^{(1)}$ of a Bose-Einstein condensate at T=0. The Bogoliubov approximation is used. Our approach points out directly the dependence on the physical parameters. Furthermore it suggests a numerical method to calculate $G^{(1)}$ without solving an eigenvector problem
Comment on "Reverse Brazil Nut Problem: Competition between Percolation and Condensation"
cond-mat.stat-mechH. Walliser
In a recent paper [Phys. Rev. Lett. 86, 3423 (2001)] D.C. Hong, P.V. Quinn and S. Luding investigated the Brazil nut problem and the reverse Brazil nut problem at fixed temperature. A new condensation versus percolation driven segregation mechanism was put forward, which has attracted much attention in the press. The proposed mechanism is incorrect.
An application of the catastrophe theory to building the model of elastic-plastic behaviour of materials. Part 2. 3D model
cond-mat.mtrl-sciL. N. Maurin, I. S. Tikhomirova
The three-dimensional elastic-plastic deformation is considered. The catastrophe theory underlies the construction of this process model. It was shown that the variety of stable states consists on elastic states and can be depicted as a lattice on plane in coordinates shearing stress intensity and shearing strain intensity.
Strong enhancement of drag and dissipation at the weak- to strong- coupling phase transition in a bi-layer system at a total Landau level filling nu=1
cond-mat.mes-hallAdy Stern, B. I. Halperin
We consider a bi-layer electronic system at a total Landau level filling factor nu =1, and focus on the transition from the regime of weak inter-layer coupling to that of the strongly coupled (1,1,1) phase (or ''quantum Hall ferromagnet''). Making the assumption that in the transition region the system is made of puddles of the (1,1,1) phase
Petter Holme, Peter Olsson
Three different vortex glass models are studied by examining the energy barrier against vortex motion across the system. In the two-dimensional gauge glass this energy barrier is found to increase logarithmically with system size which is interpreted as evidence for a low-temperature phase with zero resistivity. Associated with the large energy barriers is a
George Kastrinakis
We examine the effects of interface roughness and/or planar impurity doping in a superlattice, in the frame of a weak disorder description. We find that these two types of disorder are equivalent, and that they can be viewed as effective "bulk" disorder, with anisotropic diffusion coefficients. Our results offer quantitative insight to transport prop
Blas Echebarria, Alain Karma
We derive an equation that governs the spatiotemporal dynamics of small amplitude alternans in paced cardiac tissue. We show that a pattern-forming linear instability leads to the spontaneous formation of stationary or traveling waves whose nodes divide the tissue into regions with opposite phase of oscillation of action potential duration. This instability
Evidence for Static Magnetism in the Vortex Cores of Ortho-II YBa$_2$Cu$_3$O$_{6.50}$
cond-mat.supr-conR. I. Miller, R. F. Kiefl, J. H. Brewer, J. E. Sonier
Evidence for static alternating magnetic fields in the vortex cores of underdoped YBa$_2$Cu$_3$O$_{6+x}$ is reported. Muon spin rotation measurements of the internal magnetic field distribution of the vortex state of YBa$_2$Cu$_3$O$_{6.50}$ in applied fields of $H = 1$ T and $H = 4$ T reveal a feature in the high-field tail of the field distribution which is
High temperature superconductivity and charge segregation in a model with strong long-range electron-phonon and Coulomb interactions
cond-mat.supr-conA. S. Alexandrov, P. E. Kornilovitch
An analytical method of studying strong long-range electron-phonon and Coulomb interactions in complex lattices is presented. The method is applied to a perovskite layer with anisotropic coupling of holes to the vibrations of apical atoms. Depending on the relative strength of the polaronic shift, Ep, and the inter-site Coulomb repulsion, Vc, the system is e
Manipulating the critical temperature for the superfluid phase transition in trapped atomic Fermi gases
cond-mat.supr-conC. P. Search, H. Pu, W. Zhang, B. P. Anderson
We examine the effect of the trapping potential on the critical temperature, $T_C$, for the BCS transition to a superfluid state in trapped atomic gases of fermions. $T_C$ for an arbitrary power law trap is calculated in the Thomas-Fermi approximation. For anharmonic traps, $T_C$ can be increased by several orders of magnitude in comparison to a harmonic tra
Stochastic Resonance of Ensemble Neurons for Transient Spike Trains: A Wavelet Analysis
cond-mat.dis-nnHideo Hasegawa
By using the wavelet transformation (WT), we have analyzed the response of an ensemble of $N$ (=1, 10, 100 and 500) Hodgkin-Huxley (HH) neurons to {\it transient} $M$-pulse spike trains ($M=1-3$) with independent Gaussian noises. The cross-correlation between the input and output signals is expressed in terms of the WT expansion coefficients. The signal-to-n
S. Staggs, S. Church
In recent years the promise of experimental study of the cosmic microwave background (CMB) has been demonstrated. Herein a brief summary of the field is followed by an indication of future directions. The prospects for further revelations from the details of the CMB are excellent. The future work is well-suited to the interests of high energy physics experim
Jeremy S. Heyl, Abraham Loeb
If the potential of a scalar field, Phi, which currently provides the ``dark energy'' of the universe, has a negative minimum -M_0^4, then quantum-mechanical fluctuations could nucleate a bubble of Phi at a negative value of the potential. The bubble would expand at the speed of light. Given that no such bubble enveloped us in the past, we find that
A. Brandenburg, W. Dobler
In ordinary turbulence research it has been a long standing tradition to solve the equations in spectral space giving the best possible accuracy. This is indeed a natural choice for incompressible problems with periodic boundaries, but it is no longer optimal in many astrophysical circumstances. It is argued that lower order spatial derivatives schemes are u
Kristen Menou, Rosalba Perna, Lars Hernquist
We show that accretion disks in several compact X-ray binaries with hydrogen-depleted donors are likely subject to a thermal ionization instability, unless they are strongly irradiated. These disks are particularly interesting in that their MHD-turbulent properties in the neutral phase may be quite different from those of standard, hydrogen-rich disks.
V. Connaughton
I discuss in this paper the phenomenon of post-burst emission in BATSE gamma-ray bursts at energies traditionally associated with prompt emission. By summing the background-subtracted signals from hundreds of bursts, I find that tails out to hundreds of seconds after the trigger may be a common feature of long events (duration greater than 2s), and perhaps o
Nissim Kanekar, Jayaram N Chengalur
We present Giant Metrewave Radio Telescope (GMRT) observations of OH absorption in B3~1504+377 ($z \sim 0.673$) and PKS 1413+135 ($z \sim 0.247$). OH has now been detected in absorption towards four intermediate redshift systems, viz. the lensing galaxies towards B~0218+357 ($z \sim 0.685$; Kanekar et al. 2001) and 1830-211 ($z \sim 0.886$; Chengalur et al.
Fotis P. Gavriil, Victoria M. Kaspi, Deepto Chakrabarty
We report on long-term monitoring of anomalous X-ray pulsars (AXPs) using the Rossi X-ray Timing Explorer. Using phase-coherent timing, we find a wide variety of behaviors among the sources, ranging from high stability (in 1E 2259.1+586 and 4U 0142+61), to instabilities so severe that phase-coherent timing is not possible (in 1E 1048.1-5937). We note a corre
Ferdi Hulleman
We present recent results of our program of deep optical and near-infrared observations of AXPs. We find that the counterpart to AXP 4U 0142+61 has a peculiar spectral energy distribution. The counterpart is remarkably bright in the near-infrared, but is not detected in the B band. We also present the possible detection of a second AXP counterpart, namely th
Sabine Mengel, Matthew D. Lehnert, Niranjan Thatte, Reinhard Genzel
In order to estimate the masses of the compact, young star clusters in the merging galaxy pair, NGC 4038/4039 (``the Antennae''), we have obtained medium and high resolution spectroscopy using ISAAC on VLT-UT1 and UVES on VLT-UT2 of five such clusters. The velocity dispersions were estimated using the stellar absorption features of CO at 2.29 microns
A. A. Belyanin, E. V. Derishev, V. V. Kocharovsky, Vl. V. Kocharovsky
We present arguments in favor of the presence of free neutrons in plasmas generated by compact astrophysical objects and find conditions necessary for the formation of the neutron component. The broad range of phenomena caused by neutrons includes both dynamical (sources' variability, transition of fireballs to the two-flow regime) and kinetic (fission o
Wo-Lung Lee, Li-Zhi Fang
We show that if the primordial classical perturbations were generated by the gravitational particle creation during inflation, and followed by an evolution of quantum-to-classical transition,the time dependent correlation of these perturbations is long-tailed with a correlation time larger than the Hubble-time. Consequently, the inflationary perturbations ar
Andrew R Liddle
This article gives a brief overview of the status of attempts to constrain inflation using observations, and examines prospects for future developments.
R. Plaga
The problem in identifying the sites of origin of Galactic Cosmic Rays (CRs) is reviewed. Recent observational evidence from very-high energy (VHE, energies above 100 GeV) gamma-ray measurements is in contradiction with the surmise that synchrotron radiation from relativistic electrons is indicative for hadron acceleration. It rather points to a CR-accelerat
Numerical study of the magnetorotational instability in weakly magnetised accretion disks: Resolution dependence of the Shakura-Sunyaev alpha
astro-phP. J. Kapyla, M. J. Korpi
In this letter, we present numerical calculations made to investigate the possible resolution dependence of the Shakura & Sunyaev (1973) viscosity parameter alpha from local magnetohydrodynamic simulations of the magnetorotational instability (MRI). We find that the values of alpha do indeed depend significantly on the numerical resolution but also that when
The influence of dynamic tides on the apsidal-motion rate in close binaries with an evolved main-sequence star
astro-phB. Willems, A. Claret
The validity of the classical formula for the rate of secular apsidal motion in close binaries is investigated for a sequence of models of a 5 solar mass star ranging from the last stages of the C12 -> N14 reaction to the phase where hydrogen is exhausted in the core. For binaries with short orbital periods, the apsidal-motion rates predicted by the classica
Martin Pohl
This paper summarizes recents results in gamma-ray astronomy, most of which were derived with data from ground-based gamma-ray detectors. Many of the contributions presented at this conference involve multiwavelength studies which combine ground-based gamma-ray measurements with optical data or space-based X-ray and gamma-ray measurements. Besides measuremen
S. Zucker, D. Naef, D. W. Latham, M. Mayor
We report the detection of a low-mass companion orbiting the solar-type star HD178911B, the distant component of the stellar triple system HD178911. The variability of HD178911B was first detected using radial-velocity measurements obtained with the HIRES spectrograph mounted on the 10-m Keck1 telescope at the W.M. Keck Observatory (Hawaii, USA). We then sta
Makoto Matsumiya, Misao Sasaki, Jun'ichi Yokoyama
We investigate the possibility of reconstructing the initial spectrum of density fluctuations from the cosmic microwave background (CMB) anisotropy. As a first step toward this program, we consider a spatially flat, CDM dominated universe. In this case, it is shown that, with a good accuracy, the initial spectrum satisfies a first order differential equation
M. E. Sharina, I. D. Karachentsev, A. N. Burenkov
Long-slit observations of 4 dwarf spheroidal galaxies in the M81 group are presented. We have obtained a heliocentric velocity of globular cluster candidate located near the center of DDO78 to be +55 +- 10 km/s by cross-correlation with template stars. We estimated a heliocentric radial velocity of -116 +- 21 km/s for an HII region seen in the K 61. A red di
Jordan Kyriakidis, M. Pioro-Ladriere, M. Ciorga, A. S. Sachrajda
Results of calculations and high source-drain transport measurements are presented which demonstrate voltage-tunable entanglement of electron pairs in lateral quantum dots. At a fixed magnetic field, the application of a judiciously-chosen gate voltage alters the ground-state of an electron pair from an entagled spin singlet to a spin triplet.
E787 Collaboration
Additional evidence for the rare kaon decay K+ to pi+ neutrino-antineutrino has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211<P<229 MeV/c, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estima
Thermal Hall conductivity of marginal Fermi liquids subject to out-of plane impurities in high-$T_c$ cuprates
cond-mat.supr-conMei-Rong Li
The effect of out-of-plane impurities on the thermal Hall conductivity $κ_{xy}$ of in-plane marginal-Fermi-liquid (MFL) quasiparticles in high-$T_c$ cuprates is examined by following the work on electrical Hall conductivity $σ_{xy}$ by Varma and Abraham [Phys. Rev. Lett. 86, 4652 (2001)]. It is shown that the effective Lorentz force exerted by these impuriti
Determination of Effective Permittivity and Permeability of Metamaterials from Reflection and Transmission Coefficients
physics.class-phD. R. Smith, S. Schultz, P. Markos, C. M. Soukoulis
We analyze the reflection and transmission coefficients calculated from transfer matrix simulations on finite lenghts of electromagnetic metamaterials, to determine the effective permittivity and permeability. We perform this analysis on structures composed of periodic arrangements of wires, split ring resonators (SRRs) and both wires and SRRs. We find the r
Adam Boyarski
Noise and Malter breakdown have been studied at high rates in a test chamber having the same cell structure and gas as in the BaBar drift chamber. The chamber was first damaged by exposing it to a high source level at an elevated high voltage, until its operating current at normal voltages was below 0.5nA/cm. Additives such as water or alcohol allowed the da
Entropy of Operator-valued Random Variables: A Variational Principle for Large N Matrix Models
hep-thL. Akant, G. S. Krishnaswami, S. G. Rajeev
We show that, in 't Hooft's large N limit, matrix models can be formulated as a classical theory whose equations of motion are the factorized Schwinger--Dyson equations. We discover an action principle for this classical theory. This action contains a universal term describing the entropy of the non-commutative probability distributions. We show that
Ernest Ma, D. P. Roy
We propose a simple unified description of two recent precision measurements which suggest new physics beyond the Standard Model of particle interactions, i.e. the deviation of $\sin^2 θ_W$ in deep inelastic neutrino-nucleon scattering and that of the anomalous magnetic moment of the muon. Our proposal is also consistent with a third precision measurement, i
R. N. Mohapatra, S. Nussinov, V. L. Teplitz
It has been argued that the observed core density profile of galaxies is inconsistent with having a dark matter particle that is collisionless and alternative dark matter candidates which are self interacting may explain observations better. One new class of self interacting dark matter that has been proposed in the context mirror universe models of particle
Qiuping A. Wang, Laurent Nivanen, Alain Le Mehaute, Michel Pezeril
We show that Abe's general pseudoadditivity for entropy prescribed by thermal equilibrium in nonextensive systems holds not only for entropy, but also for energy. The application of this general pseudoadditivity to Tsallis entropy tells us that the factorization of the probability of a composite system into product of the probabilities of the subsystems
Susceptibility and dilution effects of the kagome bi-layer geometrically frustrated network. A Ga-NMR study of SrCr_(9p)Ga_(12-9p)O_(19)
cond-mat.str-elL. Limot, P. Mendels, G. Collin, C. Mondelli
We present an extensive gallium NMR study of the geometrically frustrated kagome bi-layer compound SrCr_(9p)Ga_(12-9p)O_(19) (Cr^3+, S=3/2) over a broad Cr-concentration range (.72<p<.95). This allows us to probe locally the kagome bi-layer susceptibility and separate the intrinsic properties due to the geometric frustration from those related to the site di
J. Pestieau, C. Smith
A simple method to compute QED bound state properties is presented, in which binding energy effects are treated non-perturbatively. It is shown that to take the effects of all ladder Coulomb photon exchanges into account, one can simply perform the derivative of standard QED amplitudes with respect to the external momentum. For example, the derivative of the
Luca Amendola, Domenico Tocchini-Valentini
In most models of dark energy the structure formation stops when the accelerated expansion begins. In contrast, we show that the coupling of dark energy to dark matter may induce the growth of perturbations even in the accelerated regime. In particular, we show that this occurs in the models proposed to solve the cosmic coincidence problem, in which the rati
M. Warner, S. Kutter
We give a geometric interpretation of the soft elastic deformation modes of nematic elastomers, with explicit examples, for both uniaxial and biaxial nematic order. We show the importance of body rotations in this non-classical elasticity and how the invariance under rotations of the reference and target states gives soft elasticity (the Golubovic and Lubens
Marcelo S. Berman, Luis A. Trevisan
We find a solution for exponential inflation in a Brans-Dicke generalized model, where the coupling "constant " is variable. While in General Relativity the equation of state is p is equal to minus rho, here we find p proportional to rho, where the proportionality constant is smaller than -2/3. The negativity of cosmic pressure implies acceleration o
Arkady L. Kholodenko
In previous publications (J.Geom.Phys.38 (2001) 81-139 and references therein) the partition function for 2+1 gravity was constructed for the fixed genus Riemann surface. With help of this function the dynamical transition from pseudo-Anosov to periodic (Seifert-fibered) regime was studied.In this paper the periodic regime is studied in some detail in order
Daniel Grumiller
Equipped with the tools of (spherically reduced) dilaton gravity in first order formulation and with the results for the lowest order S-matrix for s-wave gravitational scattering (P. Fischer, D. Grumiller, W. Kummer, and D. Vassilevich, gr-qc/0105034) new properties of the ensuing cross-section are discussed. We find CPT invariance, despite of the non-local
R. P. Malik
In the framework of superfield formalism, we demonstrate the existence of a new local, covariant, continuous and nilpotent (dual-BRST) symmetry for the BRST invariant Lagrangian density of a self-interacting two ($1 + 1$)-dimensional (2D) non-Abelian gauge theory (having no interaction with matter fields). The local and nilpotent Noether conserved charges co
Chandra Observations of the Components of Clusters, Groups, and Galaxies and their Interactions
astro-phW. Forman, C. Jones, M. Markevitch, A. Vikhlinin
We discuss two themes from Chandra observations of galaxies, groups, and clusters. First, we review the merging process as seen through the high angular resolution of Chandra. We present examples of sharp, edge-like surface brightness structures ``cold fronts'', the boundaries of the remaining cores of merger components and the Chandra observations o
Bing Dong, X. L. Lei
The current noise in a quantum dot coupled to two leads is investigated in the Kondo regime with and without the influence of magnetic fields by employing a finite-$U$ slave-boson mean field theory to calculate the current-current correlation function at zero temperature. The numerical results show that, depending on the energy level of the QD the Coulomb in
I. Schmelzer
We present a new staggered discretization of the Dirac operator. Doubling gives only a doublet of Dirac fermions which we propose to interpret as a physical (lepton or quark) doublet. If coupled with gauge fields, an $(1+γ^5)$ chiral interaction appears in a natural way. We define a generalization for curved background which does not require tetrad variables
G. Germán, Anupam Mazumdar, A. Pérez-Lorenzana
We study supergravity inflationary models where inflation is produced along the angular direction. For this we express the scalar component of a chiral superfield in terms of the radial and the angular components. We then express the supergravity potential in a form particularly simple for calculations involving polynomial expressions for the superpotential
L. Consoli, H. Knops, A. Fasolino
In the dynamics of the undamped Frenkel-Kontorova model with kinetic terms, we find a transition between two regimes, a floating incommensurate and a pinned incommensurate phase. This behavior is compared to the static version of the model. A remarkable difference is that, while in the static case the two regimes are separated by a single transition (the Aub
K. -I. Kondo, T. Murakami, T. Shinohara, T. Imai
We discuss the renormalization of a BRST and anti-BRST invariant composite operator of mass dimension 2 in Yang-Mills theory with the general BRST and anti-BRST invariant gauge fixing term of the Lorentz type. The interest of this study stems from a recent claim that the non-vanishing vacuum condensate of the composite operator in question can be an origin o
G. M. Minkov, O. E. Rut, A. V. Germanenko, A. A. Sherstobitov
Results of detailed investigations of the conductivity and Hall effect in gated single quantum well GaAs/InGaAs/GaAs heterostructures with two-dimensional electron gas are presented. A successive analysis of the data has shown that the conductivity is diffusive for $k_F l=25-2$ and behaves like diffusive one for $k_F l=2-0.5$ down to the temperature T=0.4 K.
Jacques Bros, Henri Epstein, Ugo Moschella
We propose a general framework for studying quantum field theory on the anti-de-Sitter space-time, based on the assumption of positivity of the spectrum of the possible energy operators. In this framework we show that the n-point functions are analytic in suitable domains of the complex AdS manifold, that it is possible to Wick rotate to the Euclidean manifo
Pijush K. Ghosh
We study the time-evolution of the two dimensional multi-component Bose-Einstein condensate in an external harmonic trap with arbitrary time-dependent frequency. We show analytically that the time-evolution of the total mean-square radius of the wave-packet is determined in terms of the same solvable equation as in the case of a single-component condensate.
S. A. Gurvitz
We consider tunneling to the continuum in a multi-dimensional potential. It is demonstrate that this problem can be treated as two separate problems: a) a bound state and b) a non-resonance scattering problem, by a proper splitting of the potential into two components. Finally we obtain the resonance energy and the partial tunneling widths in terms of the bo
Saar Rahav, Shmuel Fishman
The form factor $K(τ)$ is calculated analytically to the order $τ^3$ as well as numerically for a rectangular billiard perturbed by a $δ$-like scatterer with an angle independent diffraction constant, $D$. The cases where the scatterer is at the center and at a typical position in the billiard are studied. The analytical calculations are performed in the sem
Mei Huang, Pengfei Zhuang, Weiqin Chao
The effect of color breaking on colored quarks' chiral condensates has been investigated at zero temperature and moderate baryon density. It is found that the influence of the diquark condensate on different colored quarks is very small.
Mikhail Z. Iofa
We discuss the form of the string-loop-corrected effective action obtained by compactification of the heterotic string theory on the manifold $K3\times T^2$ or on its orbifold limit and the loop-corrected magnetic black hole solutions of the equations of motion. Effective 4D theory has N=2 local supersymmetry. Using the string-loop-corrected prepotential of
Random Magnetism in $S=1/2$ Heisenberg Chains with Bond Alternation and Randomness on the Strong Bonds
cond-mat.str-elKazuo Hida
The $S=1/2$ Heisenberg chains with bond alternation and randomness on the strong bonds are studied by the density matrix renormalization group method. It is assumed that the odd-th bond is antiferromagnetic with strength $J$ and even-th bond can take the values $\JA$ and $\JF$ $ (\JA > J > 0 > \JF)$ randomly. The ground state of this model interpolates betwe
L. Feher, A. Gabor
In this note we complement recent results on the exchange $r$-matrices appearing in the chiral WZNW model by providing a direct, purely finite-dimensional description of the relationship between the monodromy dependent 2-form that enters the chiral WZNW symplectic form and the exchange $r$-matrix that governs the corresponding Poisson brackets. We also devel
Sergei Sakovich
We apply the Painleve test for integrability to a new discrete (differential-difference) nonlinear Schrodinger equation introduced by Leon and Manna. Since the singular expansions of solutions of this equation turn out to contain nondominant logarithmic terms, we conclude that the studied equation is nonintegrable. This result supports the observation of Lev
D. Karabali, V. P. Nair, A. P. Polychronakos
The energy spectrum of a nonrelativistic particle on a noncommutative sphere in the presence of a magnetic monopole field is calculated. The system is treated in the field theory language, in which the one-particle sector of a charged Schroedinger field coupled to a noncommutative U(1) gauge field is identified. It is shown that the Hamiltonian is essentiall
Rui Zhang, Yi-Bing Ding, Xue-Qian Li, Philip R. Page
This work investigates whether the observed 1^-+ exotic mesons are molecular states. We first use a potential model to calculate the spectra and lifetimes of the f_0(980) and a_0(980), taken to be loosely bound molecular states of K Kbar, then apply the same scenario to the 1^-+ exotic states pi_1(1400) and pi_1(1600), assuming them to be pi eta(1295) and pi
N. C. Menicucci, Carlton M. Caves
We construct a local realistic hidden-variable model that describes the states and dynamics of bulk-ensemble NMR information processing up to about 12 nuclear spins. The existence of such a model rules out violation of any Bell inequality, temporal or otherwise, in present high-temperature, liquid-state NMR experiments. The model does not provide an efficien
Karol A. Penson, Allan I Solomon
We construct coherent states using sequences of combinatorial numbers such as various binomial and trinomial numbers, and Bell and Catalan numbers. We show that these states satisfy the condition of the resolution of unity in a natural way. In each case the positive weight functions are given as solutions of associated Stieltjes or Hausdorff moment problems,
Nguyen Ba An, Truong Minh Duc
We investigate the Nth order amplitude squeezing in the fan-state |ξ;2k,f>_F which is a linear superposition of the 2k-quantum nonlinear coherent states. Unlike in usual states where an ellipse is the symbol of squeezing, a 4k-winged flower results in the fan state. We first derive the analytical expression of squeezing for arbitrary k, N, f and then study i
Jiangfeng Du, Xiaodong Xu, Hui Li, Xianyi Zhou
We investigate Nash Equilibrium in the quantum Battle of Sexes Game. We find the game has infinite Nash Equilibria and all of them leads to the asymmetry result. We also show that there is no unique but infinite Nash Equilibrium in it if we use the quantizing scheme proposed by Eisert et al and the two players are allowed to adopt any unitary operator as his
J. Chiba, H. Fujii, K. Furukawa, N. Kamikubota
The current status of the control system for a new high intensity proton accelerator, the JAERI-KEK Joint Project, is presented. The Phase 1 of the Joint-Project has been approved and recently started its construction at JAERI site at Tokai. The first beam commissioning is scheduled in 2006. In parallel with it, a 60-MeV Linac is now being constructed at KEK
A. Biocca, W. Brown, E. Domning, K. Fowler
The Advanced Light Source was commissioned 10 years ago using the newly constructed control system. Further experience with the control system was reported in 1993. In this publication, we report on recent experience with the operation and especially growth of the computer control system and expansion to accommodate the new superconducting bend magnets and f
Y. G. Yi
A statistical-mechanical treatment of collision leads to a formal connection with transition-state theory, suggesting that collision theory and transition-state theory might be joined ultimately as a collision induced transition state theory.
Extension of Kohn-Sham theory to excited states by means of an off-diagonal density array
physics.atom-phAbraham Klein, Reiner M. Dreizler
Early work extending the Kohn-Sham theory to excited states utilized an ensemble average of the Hamiltonian considered as a functional of the corresponding average density. We propose and develop an alternative that utilizes the matrix elements of the density operator taken between any two states of the included space. The new theory is also based on a varia
Yu. N. Uzikov
Quasi-binary reaction of the deuteron breakup $p+d\to (pp)+n$ with the final proton-proton pair $(pp)$ in the $^1S_0$ state is analyzed at initial energies $0.5 - 2$ GeV in the kinematics of backward elastic pd-scattering $pd\to dp$. On the basis of the main mechanisms of the $pd\to dp$ process, including initial and final state interaction, we show that unp
C. Giusti
The attempts to investigate correlations in electromagnetically induced one- and two-nucleon knockout are reviewed. The theoretical framework for cross section calculations is outlined and some results are presented for the exclusive $^{16}$O($e,e'p)^{15}$N and $^{16}$O($e,e'pp)^{14}$C reactions. For the ($e,e'p$) reaction attention is focussed o
Yu. N. Uzikov
Available data on large-angle nucleon-deuteron elastic scattering $Nd\to dN$ below the pion threshold give a signal for three-body forces. There is a problem of separation of possible subtle aspects of these forces from off-shell effects in two-nucleon potentials. By considering the main mechanisms of the process, we show qualitatively that in the quasi-bina
Enhanced excitation of Giant Pairing Vibrations in heavy-ion reactions induced by weakly-bound projectiles
nucl-thL. Fortunato, W. von Oertzen, H. M. Sofia, A. Vitturi
The use of radioactive ion beams is shown to offer the possibility to study collective pairing states at high excitation energy, which are not usually accessible with stable projectiles because of large energy mismatch. In the case of two-neutron stripping reactions induced by 6He, we predict a population of the Giant Pairing Vibration in 208Pb or 116Sn with
Andrea Meucci
Nuclear transparency in (e,e'p) reactions is evaluated in a fully relativistic distorted wave impulse approximation model. The relativistic mean field theory is used for the bound state and the Pauli reduction for the scattering state, which is calculated from a relativistic optical potential. Results for selected nuclei are displayed in a Q^2 range betw
Emily S. C. Ching, K. M. Pang
We study numerically the dependence of heat transport on the maximum velocity and shear rate of physical circulating flows, which are prescribed to have the key characteristics of the large-scale mean flow observed in turbulent convection. When the side-boundary thermal layer is thinner than the viscous boundary layer, the Nusselt number (Nu), which measures
Saar Rahav, Shmuel Fishman
The statistics of energy levels of a rectangular billiard, that is perturbed by a strong localized potential, are studied analytically and numerically, when this perturbation is at the center or at a typical position. Different results are found for these two types of positions. If the scatterer is at the center, the symmetry leads to additional contribution
Quasi-classical $\dbar$-method: Generating equations for dispersionless integrable hierarchies
nlin.SIL. V. Bogdanov, B. G. Konopelchenko, L. Martinez Alonso
The quasi-classical $\bar{\partial}$-dressing method is used to derive compact generating equations for dispersionless hierarchies. Dispersionless Kadomtsev-Petviashvili (KP) and two-dimensional Toda lattice (2DTL) hierarchies are considered as illustrative examples.
Self-duality, four-forms, and the eight-dimensional Yang-Mills/Dittmann-Bures field over the three-level quantum systems
math-phPaul B. Slater
Utilizing a number of results of Dittmann, we investigate the nature of the Yang-Mills field over the eight-dimensional convex set, endowed with the Bures metric, of three-level quantum systems. Parallelling the decomposition of eight-dimensional Euclidean fields by Corrigan, Devchand, Fairlie and Nuyts, as well as Figueoroa-O'Farrill and others, we inve
Geoffrey Buhl
We develop a spanning set for weak modules of C_2 co-finite vertex operator algebras. This spanning set has finiteness properties that we use to show weak modules are C_n co-finite and A_n(M) is finite dimensional.
A Tsemo
We study the notion of geometric structures for toposes: This generalizes the notion of (X,G) manifolds. We give some applications to algebraic geometry
A. Melin, J. Sjoestrand
For a class of non-selfadjoint h-pseudodifferential operators in dimension 2, we determine all eigenvalues in an h-independent domain in the complex plane and show that they are given by a Bohr-Sommerfeld quantization condition. No complete integrability is assumed, and as a geometrical step in our proof, we get a KAM-type theorem (without small divisors) in
A. Melin, J. Sjoestrand
Consider an h-pseudodifferential operator P, whose symbol extends holomorphically to a tubular neighborhood of the real phase space and converges sufficiently fast to 1, so that the determinant of P is well-defined. We show that the modulus of this determinant is asymptotically bounded by an exponential of the integral of the logarithm of the modulus of the
Alberto S. Cattaneo, Giovanni Felder, Lorenzo Tomassini
We review our construction of star-products on Poisson manifolds and discuss some examples. In particular, we work out the relation with Fedosov's original construction in the symplectic case.
T. D. Palev, N. I. Stoilova, J. Van der Jeugt
As an alternative to Chevalley generators, we introduce Jacobson generators for the quantum superalgebra $U_q[sl(n+1|m)]$. The expressions of all Cartan-Weyl elements of $U_q[sl(n+1|m)]$ in terms of these Jacobson generators become very simple. We determine and prove certain triple relations between the Jacobson generators, necessary for a complete set of su
Gavril Farkas, Angela Gibney
We compute the Mori cone of curves of the moduli space \M_{g,n} of stable n-pointed curves of genus g in the case when g and n are relatively small. For instance, we show that for g<14 every curve in \M_g is numerically equivalent to an effective sum of 1-strata (loci of curves with 3g-4 nodes). We also prove that the nef cone of \M_{0,6} is composed of 11 n
Generalized Riemann-Hilbert Transmission and Boundary Value Problems, Fredholm Pairs and Bordisms
math.KTBogdan Bojarski, Andrzej Weber
We present classical and generalized Riemann-Hilbert problem in several contexts arising from $K$-theory and bordism theory. The language of Fredholm pairs turns out to be useful and unavoidable. We propose an abstract formulation of a notion of bordism in the context of Hilbert spaces equipped with splittings.
Franc Forstneric
Let X and Y be complex manifolds. One says that maps from X to Y satisfy the Oka principle if the inclusion of the space of holomorphic maps from X to Y into the space of continuous maps is a weak homotopy equivalence. In 1957 H. Grauert proved the Oka principle for maps from Stein manifolds to complex Lie groups and homogeneous spaces, as well as for sectio
Oleg Shvedov
Semiclassical mechanics of systems with first-class constraints is developed. Starting from the quantum theory, one investigates such objects as semiclassical states and observables, semiclassical inner product, semiclassical gauge transformations and evolution. Quantum mechanical semiclassical substitutions (not only the WKB-ansatz) can be viewed as "co
Keith R. Dienes, Arash Mafi
By studying the effects of the shape moduli associated with toroidal compactifications, we demonstrate that Planck-sized extra dimensions can cast significant ``shadows'' over low-energy physics. These shadows can greatly distort our perceptions of the compactification geometry associated with large extra dimensions, and place a fundamental limit on
Kaare Borchsenius
We examine the structure of the Clifford algebra associated with a Hermitian bilinear form and apply the result to a dynamical model of the relativistic point particle. The dynamics of the particle is described by a Dirac spinor with components in a Clifford algebra. This spinor determines, through the Clifford algebra, both the space-time coordinates and th
Peter Mattsson
This thesis considers massive field theories in 1+1 dimensions known as affine Toda quantum field theories. We first consider the boundary sine-Gordon model, deriving a complete picture of the boundary bound state structure for general integrable boundary conditions, and then more general ATFTs in the bulk, discovering a "generalised bootstrap" equat
Matthias R Gaberdiel
A comprehensive introduction to logarithmic conformal field theory, using an algebraic point of view, is given. A number of examples are explained in detail, including the c=-2 triplet theory and the k=-4/3 affine su(2) theory. We also give some brief introduction to the work of Zhu.