June 2000 arXiv papers — page 20

Alexander A. Osipov, Brigitte Hiller

We use a proper-time regularization to define the one-loop fermion determinant for the case in which explicit chiral symmetry breaking takes place. We show how to obtain the polynomial by which the standard definition of lndetD needs to be modified in order to arrive at the fermion determinant whose transformation properties are consistent with the general s

V. Gogohia

We have formulated new quantum model of the QCD vacuum using the effective potential approach for composite operators. It is based on the existence and importance of such kind of the nonperturbative, topologically nontrivial excitations of gluon field configurations, which can be effectively correctly described by the $q^{-4}$-type behavior of the full gluon

M. Moretti

The ALPHA algorithm to evaluate the exact, tree-level matrix elements is reviewed in the context of multi-parton processes in QCD. The algorithm is suited for the authomatic calculation of tree-level scattering amplitudes and allows for straightforward inclusion of mass effects. It's CPU cost grows like K^n (K constant, n number of external particles) as

A. B. Kaidalov, L. A. Kondratyuk, D. V. Tchekin

The electromagnetic form factors of pion and nucleon are considered within the framework of the Quark-Gluon Strings Model, where the dependence of the form factors on $q^2$ is determined by the intercept of a dominant Regge trajectory and Sudakov form factor. The analytical expressions for the form factors found in the time-like region can be directly contin

Tatsumi Aoyama, Yoshio Kikukawa

We consider a lattice implementation of the eta-invariant, using the complex phase of the determinant of the simplified domain-wall fermion, which couples to an interpolating five-dimensional gauge field. We clarify the relation to the effective action for chiral Ginsparg-Wilson fermions. The integrability, which holds true for anomaly-free theories in the c

S. Cheluvaraja

We investigate some properties of thick vortices and thick monopoles in the SU(2) lattice gauge theory by inserting operators which create these excitations. Some quantities associated with the dynamical behaviour of thick vortices and thick monopoles are studied. We measure the derivative of the free energy of the vortex with respect to the coupling and we

Giuseppe Iacobucci

The data collected with the H1 and ZEUS detectors during the running period 1994-99 are used to give an experimental review on the proton structure functions and the neutral current and charged current large Q^2 cross sections in e^\pm p scattering at HERA.

O. Schneider

Recent heavy flavour results from the LEP experiments are presented. These include a search for new physics in rare B decays, a new model-independent measurement of the b-quark fragmentation function at the Z peak, updated measurements of |Vcb|, results on DeltaGamma_s, searches for B0s oscillations, as well as a new measurement of sin(2beta). Many combined

Mario A. Castagnino, Fabian H. Gaioli, Daniel M. Sforza

A very simplified model of the Universe is considered in order to propose an alternative approach to the irreversible evolution of the Universe at very early times. The entropy generation at the quantum stage can be thought as a consequence of an instability of the system. Then particle creation arises from this instability.

Soon-Tae Hong, Won Tae Kim, Yong-Wan Kim, Young-Jai Park

We obtain (3+3)- or (3+2)-dimensional global flat embeddings of four uncharged and charged scalar-tensor theories with the parameters B or L in the (2+1)-dimensions, which are the non-trivially modified versions of the Banados-Teitelboim-Zanelli (BTZ) black holes. The limiting cases B=0 or L=0 exactly are reduced to the Global Embedding Minkowski Space (GEMS

S. Manoff

The theory of spaces with different (not only by sign) contravariant and covariant affine connections and metrics [}$(\bar{L}_n,g)$\QTR{it}{-spaces] is worked out within the framework of the tensor analysis over differentiable manifolds and in a volume necessary for the further considerations of the kinematics of vector fields and the Lagrangian theory of te

Ion Androutsopoulos, John Koutsias, Konstantinos V. Chandrinos, George Paliouras

It has recently been argued that a Naive Bayesian classifier can be used to filter unsolicited bulk e-mail ("spam"). We conduct a thorough evaluation of this proposal on a corpus that we make publicly available, contributing towards standard benchmarks. At the same time we investigate the effect of attribute-set size, training-corpus size, lemmatizat

Boris Fain, Michael Levitt

We present a novel technique of sampling the configurations of helical proteins. Assuming knowledge of native secondary structure, we employ assembly rules gathered from a database of existing structures to enumerate the geometrically possible three-dimensional arrangements of the constituent helices. We produce a library of possible folds for twenty-five he

P. L. Krapivsky, Satya N. Majumdar

We study a random bisection problem where an initial interval of length x is cut into two random fragments at the first stage, then each of these two fragments is cut further, etc. We compute the probability P_n(x) that at the n-th stage, each of the 2^n fragments is shorter than 1. We show that P_n(x) approaches a traveling wave form, and the front position

K. Capelle, G. Vignale

It is shown that, contrary to widely held beliefs, the potentials of spin-density-functional theory (SDFT) are not unique functionals of the spin densities. Explicit examples of distinct sets of potentials with the same ground-state densities are constructed, and general arguments that uniqueness should not occur in SDFT and other generalized density-functio

I. A. Zaliznyak, J. P. Hill, J. M. Tranquada, R. Erwin

We present elastic and quasielastic neutron scattering measurements characterizing peculiar short-range charge-orbital and spin order in the layered perovskite material La1.5Sr0.5CoO4. We find that below Tc~750 K holes introduced by Sr doping lose mobility and enter a statically ordered {\it charge glass} phase with loosely correlated checkerboard arrangemen

P. Ilg, I. V. Karlin, S. Succi

Exact relaxation times and eigenfunctions for a simple mechanical model of polymer dynamics are obtained using supersymmetry methods of quantum mechanics. The model includes the finite extensibility of the molecule and does not make use of the self-consistently averaging approximation. The finite extensibility reduces the relaxation times when compared to a

Vito Latora, Andrea Rapisarda

The Hamiltonian Mean Field model describes a system of N fully-coupled particles showing a second-order phase transition as a function of the energy. The dynamics of the model presents interesting features in a small energy region below the critical point. In particular, when the particles are prepared in a ``water bag'' initial state, the relaxation

R. Onofrio, C. Raman, J. M. Vogels, J. Abo-Shaeer

We have studied the hydrodynamic flow in a Bose-Einstein condensate stirred by a macroscopic object, a blue detuned laser beam, using nondestructive {\em in situ} phase contrast imaging. A critical velocity for the onset of a pressure gradient has been observed, and shown to be density dependent. The technique has been compared to a calorimetric method used

Q-Han Park, J. H. Eberly

We present a new model of BEC dynamics based on strong confinement near the ground state. The model predicts oscillations in a two-component condensate, based on interference of non-spreading wave packets moving within a pair of tilted nearly square potentials. The oscillations are similar to those recently reported for a magnetically trapped $^{87}$Rb conde

Sumiyoshi Abe, S. Martinez, F. Pennini, A. Plastino

Based on the prescription termed the optimal Lagrange multipliers formalism for extremizing the Tsallis entropy indexed by q, it is shown that key aspects of the treatment of the ideal gas problem are identical in both the nonextensive and extensive cases.

Sadhan K. Adhikari

We study the Bose-Einstein condensation of an interacting gas with attractive interaction confined in a harmonic trap using a semiclassical two-fluid mean-field model. The condensed state is described by converged numerical solution of the Gross-Pitaevskii equation. By solving the system of coupled equations of this model iteratively we obtain converged resu

E. Trizac, A. Barrat

The connection between granular gases and sticky gases has recently been considered, leading to the conjecture that inelastic collapse is avoided for space dimensions higher than 4. We report Molecular Dynamics simulations of hard inelastic spheres in dimensions 4, 5 and 6. The evolution of the granular medium is monitored throughout the cooling process. The

G. Bellessa, N. Vernier, B. Barbara, D. Gatteschi

We reply to the comment of Chudnovsky and Garanin on the tunneling rate in Mn_{12}.

A. Bonnefont, F. Argoul, M. Z. Bazant

We investigate the subtle effects of diffuse charge on interfacial kinetics by solving the governing equations for ion transport (Nernst-Planck) with realistic boundary conditions representing reaction kinetics (Butler-Volmer) and compact-layer capacitance (Stern) in the asymptotic limit $ε= λ_D/L \to 0$, where $λ_D$ is the Debye screening length and $L$ is

Stephen J. Cornell, Michael R. Swift, Alan J. Bray

We refute the arguments by Anton in cond-mat/0004390, which set out to disprove the existence of a collapse transition for a randomly forced inelastic particle.

I. V. Stasyuk, A. M. Shvaika, K. V. Tabunshchyk

A method of the self-consistent calculation of the thermodynamical and correlation functions is presented. This approach is based on the GRPA (generalized random phase approximation) scheme with the inclusion of the mean field corrections. The numerical research shows that interaction between the electron and pseudospin subsystems leads to the possibility of

K. V. Tabunshchyk

The purpose of this article is to present the thermodynamics of the pseudospin-electron model in the case of the different type interactions between pseudospins. First, we provide an overview of the results of works which deal with the theoretical investigation of the pseudospin-electron model with the inclusion of the direct pseudospin-pseudospin interactio

I. V. Stasyuk, A. M. Shvaika, K. V. Tabunshchyk

Thermodynamics of a pseudospin-electron model without correlations is investigated. The correlation functions, the mean values of pseudospin and particle number, as well as the thermodynamic potential are calculated. The calculation is performed by a diagrammatic method in the mean field approximation. Single-particle Green functions are taken in the Hubbard

K. Johnsen, G. M. Kavoulakis

We examine the absorption spectrum of electromagnetic radiation from excitons, where an exciton in the $1s$ state absorbs a photon and makes a transition to the $2p$ state. We demonstrate that the absorption spectrum depends strongly on the quantum degeneracy of the exciton gas, and that it will generally manifest many-body effects. Based on our results we p

Frantisek Slanina

We study the role of imitation within the Minority Game model of market. The players can exchange information locally, which leads to formation of groups which act as if they were single players. Coherent spatial areas of rich and poor agents result. We found that the global effectivity is optimized at certain value of the imitation probability, which decrea

Atsuya Kumagai, Masahiko Hayashi, Hiromichi Ebisawa

We study the two-dimensional spin-charge separated Ginzburg-Landau theory containing U(1) gauge interactions as a semi-phenomenological model describing fluctuating condensates in high temperature superconductivity. Transforming the original GL action, we abstract the effective action of Cooper pair. Especially, we clarify how Cooper pair correlation evolves

I. Kakeya, T. Wada, R. Nakamura, K. Kaodowaki

Josephson plasma resonance measurements under magnetic fields parallel to the CuO_2 layers as functions of magnetic field, temperature, and microwave frequency have been performed in Bi_2Sr_2CaCu_2O_{8+δ} single crystals with doping range being from optimal to under-doped side. The feature of the resonance is quite unique and cannot be explained by the conve

J. Mirkovic, S. E. Savel'ev, E. Sugahara, K. Kadowaki

The vortex lattice melting transition in single crystals Bi2Sr2CaCu2O8+d was studied by the in-plane resistivity measurements in magnetic fields tilted away from the c-axis to the ab-plane. In order to avoid the surface barrier effect which hinders the melting transition in the conventional transport measurements, we used the Corbino geometry of electric con

Guo-qing Zheng, H. Ozaki, W. G. Clark, Y. Kitaoka

From measurements of the ^{63}Cu Knight shift (K) and the nuclear spin-lattice relaxation rate (1/T_{1}) under magnetic fields from zero up to 28 T in the slightly overdoped superconductor TlSr_{2}CaCu_{2}O_{6.8} (T_{c}=68 K), we find that the pseudogap behavior, {\em i.e.}, the reductions of 1/T_{1}T and K above T_{c} from the values expected from the norma

M. Abolfath, T. Jungwirth, J. Brum, A. H. MacDonald

We present a theory of magnetic anisotropy in ${\rm III}_{1-x}{\rm Mn}_{x}{\rm V}$ diluted magnetic semiconductors with carrier-induced ferromagnetism. The theory is based on four and six band envelope functions models for the valence band holes and a mean-field treatment of their exchange interactions with ${\rm Mn}^{++}$ ions. We find that easy-axis reorie

L. Bronfman, S. Casassus, J. May, L. -A. Nyman

We present the azimuthally averaged radial distribution of 748 regions of OB star formation in the whole galactic disk, based on our previous CS(2-1) survey of UC H II regions. Embedded massive stars produce a total FIR luminosity of 1.39E8 Lsun within the range 0.2<R/Ro<2 in galactocentric radius. We find 492 massive star forming regions within the solar ci

A. Rosen, P. E. Hardee

We extend investigations of mass entrainment by jets, which previously have focused on cylindrical supermagnetosonic jets and expanding trans-Alfvénic jets, to a set of expanding supermagnetosonic jets. We precess these jets at the origin to excite the helical mode of the Kelvin-Helmholtz (or KH) instability, in order to compare the results with predictions

E. Breitmoser, M. Camenzind

We present an analytical model for the magnetic flux surfaces for rapidly rotating magnetized young stellar objects which is based on ideal, stationary, axisymmetric magnetohydrodynamics. The resulting cold wind solutions reproduce observed wind velocities of a few hundred \kms$ $ and the outer jet radi us for a collimated jet of several thousand stellar rad

S. Leon, G. Meylan, F. Combes

Large-field multi-color images of 20 galactic globular clusters are used to investigate the presence of tidal tails around these stellar systems. Field and cluster stars are sorted with the help of color-magnitude diagrams, and star-count analysis is performed on the selected cluster stars in order to increase the signal-to-noise ratio of their surface densi

Etienne Parizot

From a recent re-analysis of the available data, Be and B Galactic evolution appears to show evidence for a two-slope behaviour with respect to O. The inferred Be/O abundance ratio in halo stars is constant at very low metallicity (primary behaviour) and increases proportionally to O/H at high metallicity (secondary behaviour). We show that this can be expla

Wolfgang Becken, Peter Schmelcher

The electronic structure of the helium atom in the magnetic field regime B=0-100a.u. is investigated, using a full configuration interaction approach which is based on a nonlinearly optimized anisotropic Gaussian basis set of one-particle functions. The corresponding generalized eigenvalue problem is solved for the magnetic quantum number M=-1 and for both e

Martin A. Zwaan

High Velocity Clouds (HVCs) have recently attracted renewed attention as being long lived, massive dark matter dominated clouds of primordial composition distributed throughout the Local Group. In this picture the HVCs would contain a few times 10^7 M_sun of HI and would be at distances of a few hundred kpc to 1.5 Mpc from the Local Group barycenter. If this

F. De Paolis, G. Ingrosso, D. Orlando

GRBs are nowadays a rather well understood phenomenon in the soft (KeV-MeV) $γ$-ray energy band, while only a few GRBs have been observed at high photon energies ($E_γ \ut > 1$ GeV). It is also widely recognized that GRBs accelerate protons to relativistic energies and that dense media are often present nearby the sources. Within this framework we compute in

F. Bertoldi, C. L. Carilli, K. M. Menten, F. Owen

We present millimeter wavelength detections of three faint sources that are most likely high-redshift starburst galaxies. For one of the sources, which was previously discovered with SCUBA at 850 mu m, we present a detection with the IRAM interferometer at 240 GHz (1.25 mm) that shows the object unresolved at an angular resolution of 2.&#39;&#39;5, and coinc

Mayeul Arminjon

A scalar theory of gravitation with a preferred reference frame (PRF) is considered, that accounts for special relativity and reduces to it if the gravitational field cancels. The gravitating system consists of a finite number of perfect-fluid bodies. An &#34; asymptotic &#34; post-Newtonian (PN) approximation scheme is used, allowing an explicit weak-field

L. Nobili, R. Turolla, L. Zampieri, T. Belloni

In this Letter we propose a simple thermal comptonization model to account for the observed properties of the phase lags associated to the ``plateau&#39;&#39; intervals of GRS 1915+105. By invoking a temperature stratification in a corona and assuming that the optical depth of the comptonizing region increases as the disk inner radius moves inward, we are ab

D. Rigopoulou, A. Franceschini, H. Aussel, R. Genzel

We report the results of near-infrared VLT-ISAAC spectroscopy of a sample of 12 galaxies at z = 0.4-1.4, drawn from the ISOCAM survey of the Hubble Deep Field South. We find that the rest frame R-band spectra of the ISOCAM galaxies resemble those of powerful dust-enshrouded starbursts. Halpha emission is detected in 11 out of 12 objects down to a flux limit

V. Dhawan, I. F. Mirabel, L. F. Rodriguez

Radio imaging of the microquasar GRS 1915+105 with the Very Long Baseline Array (VLBA) during various flaring, quiescent, or oscillatory states of the black hole binary, always resolves the nucleus as a compact jet of length about 10.lambda_cm AU. On scales of 2.5-7AU, the nucleus has brightness temperature T_B > 10^9 K, and its properties are better fit by

G. Z. Adunas, E. Rodriguez-Milla, D. V. Ahluwalia

We emphasize that a specific aspect of quantum gravity is the absence of a super-selection rule that prevents a linear superposition of different gravitational charges. As an immediate consequence, we obtain a tiny, but observable, violation of the equivalence principle, provided, inertial and gravitational masses are not assumed to be operationally identica

K. Buckley, T. Fugleberg, A. Zhitnitsky

It has been suggested recently that an arbitrary induced theta-vacuum state could be created in heavy ion collisions. If such a state can be created, it would decay by various mechanisms to the fundamental theta=0 state which is the true ground state of our world. In the following we will discuss the possibility of studying this unusual state through the emi

A. Gorsky, K. Selivanov

We describe spontaneous creation of the Brane World in $AdS_{5}$ with external field. The resulting Brane World consists of a flat 4d spatially finite expanding Universe and curved expanding &#34;regulator&#34; branes. No negative tension branes are involved.

Shamit Kachru, Sheldon Katz, Albion Lawrence, John McGreevy

We discuss the generation of superpotentials in four-dimensional, N = 1 supersymmetric field theories arising from type IIA D6-branes wrapped on supersymmetric three-cycles of a Calabi-Yau threefold. In general, nontrivial superpotentials arise from sums over disc instantons. We find several examples of special Lagrangian three-cycles with nontrivial topolog

G. J. Wasserburg, Y. -Z. Qian

We apply the phenomenological model used to explain the abundances of Fe and r-process elements in very metal-poor stars in the Galaxy to [Fe/H] of damped Ly alpha systems. It is assumed that the first stars formed after the Big Bang were very massive and promptly enriched the interstellar medium to [Fe/H] ~ -3, at which metallicity formation of normal stars

HAPPEX collaboration, K. A. Aniol

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) +- 0.56(syst) ppm at the kinematic point theta_lab = 12.3 degrees and Q^2 = 0.477 (GeV/c)^2. The measurement implies that the value for the strange form factor (G_E^s + 0.392 G_M^s) = 0.025 +- 0.

P. Butera, M. Comi

Using a renormalized linked-cluster-expansion method, we have extended to order $β^{23}$ the high-temperature series for the susceptibility $χ$ and the second-moment correlation length $ξ$ of the spin-1/2 Ising models on the sc and the bcc lattices. A study of these expansions yields updated direct estimates of universal parameters, such as exponents and amp

V. N. Zavaritsky, M. Springford, A. S. Alexandrov

The out-of-plane resistance and the resistive upper critical field of BSCCO-2212 single crystals with Tc=91-93 K have been measured in magnetic fields up to 50 T over a wide temperature range. The results are characterised by a positive linear magnetoresistance in the superconducting state and a negative linear magnetoresistance in the normal state. The zero

A. N. Taylor, A. Berera

We investigate the phenomenology of warm inflation and present generic results about the evolution of the inflaton and radiation fields. The general conditions required for warm inflation to take place are derived and discussed. A comprehensive approach is presented for the generation of thermally induced adiabatic and isocurvature perturbations and the ampl

Avinash Dhar, Spenta R. Wadia

We derive an RG flow equation that is satisfied by the regularized partition function for noncritical strings in background fields. The flow refers to change in the position of a ``boundary&#39;&#39; in the liouville direction. The boundary is required to regularize the ultraviolet divergences in the partition function coming from integration over world-shee

J. A. K. Freire, F. M. Peeters, A. Matulis, V. N. Freire

The trapping of excitons in a semiconductor quantum well due to a circular symmetric nonhomogeneous magnetic field is studied. The effect of the spin state of the exciton on its trapping energy is analyzed, and the importance of the interaction of the orbital and spin Zeeman effect as compared to the diamagnetic term in the exciton Hamiltonian is emphasized.

M. Boettcher, C. L. Fryer

We investigate the potentially observable prompt or delayed X-ray spectral features from the currently popular gamma-ray burst (GRB) models. During the evolution of many GRB progenitors, a disk around the central GRB source is produced. Shock heating as the GRB ejecta collide with the disk may produce observable X-ray features. We first summarize predictions

Martin Schvellinger

We study solutions of the one-loop beta-functions of the critical bosonic string theory in the framework of the Renormalization Group (RG) approach to string theory, considering explicitly the effects of the 21 extra dimensions. In the RG approach the 26-dimensional manifold is given in terms of a four dimensional Minkowski spacetime times R and a 21-dimensi

Ph. Bourges, B. Keimer, L. P. Regnault, Y. Sidis

A critical examination of the spin dynamics in high-$T_C$ cuprates is made on the light of inelastic neutron scattering results obtained by different groups. Recent neutron data show that incommensurate magnetic peaks in YBCO belong to the same excitation as the resonance peak observed at $(π/a,π/a)$. Being only observed in the superconducting state, the inc

Jose I. Illana, Tord Riemann

Recent experimental results suggest that the neutrinos of the Standard Model are massive, though light. Therefore they may mix with each other giving rise to lepton flavour or even lepton number violating processes, depending on whether they are Dirac or Majorana particles. Furthermore, the lightness of the observed neutrinos may be explained by the existenc

Jes Madsen

The low velocity part of a kinetic equilibrium dark matter distribution has higher phase space density and is more easily incorporated in formation of a low mass galaxy than the high velocity part. For relativistically decoupling fermions (bosons), this explains one (two) orders of magnitude of the observed trend, that phase space densities in dark matter ha

Tohru Kawamoto, Yoshihiro Asai, Shuji Abe

A novel microscopic mechanism of bi-directional structural changes is proposed for the photo-induced magnetic phase transition in Co-Fe Prussian blue analogues on the basis of ab initio quantum chemical cluster calculations. It is shown that the local potential energies of various spin states of Co are sensitive to the number of nearest neighbor Fe vacancies

A. V. Silhanek, J. R. Thompson, L. Civale, D. McK. Paul

We have studied the pinning force density Fp of YNi_2B_2C superconductors for various field orientations. We observe anisotropies both between the c-axis and the basal plane and within the plane, that cannot be explained by usual mass anisotropy. For magnetic field $H \parallel c$, the reorientation structural transition in the vortex lattice due to nonlocal

Leonid Malyshkin, Russell Kulsrud

Parallel thermal conduction along stochastic magnetic field lines may be reduced because the heat conducting electrons become trapped and detrapped between regions of strong magnetic field (magnetic mirrors). The problem reduces to a simple but realistic model for diffusion of mono-energetic electrons based on the fact that when there is a reduction of diffu

F. M. Woodward, R. Brüschweiler

Experimental NMR implementations of the Deutsch-Josza quantum algorithm based on pesudo-pure spin states exhibit an exponential sensitivity scaling with the number of qubits. By employing truly mixed spin states in spin Liouville space, where molecules with different nuclear spin configurations represent different input states, the Deutsch-Josza problem can

Adel M. Awad, Clifford V. Johnson

We present two examples of non-trivial field theories which are scale invariant, but not conformally invariant. This is done by placing certain field theories, which are conformally invariant in flat space, onto curved backgrounds of a specific type. We define this using the AdS/CFT correspondence, which relates the physics of gravity in asymptotically Anti-

P. van Loock, Samuel L. Braunstein

We show that the continuous-variable analogues to the multipartite entangled Greenberger-Horne-Zeilinger states of qubits violate Bell-type inequalities imposed by local realistic theories. Our results suggest that the degree of nonlocality of these nonmaximally entangled continuous-variable states, represented by the maximum violation, grows with increasing

Domingo J. Louis-Martinez

An extension of the Weyl-Wigner-Moyal formulation of quantum mechanics suitable for a Dirac quantized constrained system is proposed. In this formulation, quantum observables are described by equivalent classes of Weyl symbols. The Weyl product of these equivalent classes is defined. The new Moyal bracket is shown to be compatible with the Dirac bracket for

J. C. Lemm, J. Uhlig

A Bayesian approach is developed to determine quantum mechanical potentials from empirical data. Bayesian methods, combining empirical measurements and &#34;a priori&#34; information, provide flexible tools for such empirical learning problems. The paper presents the basic theory, concentrating in particular on measurements of particle coordinates in quantum

Stefan Scheel, Tomas Opatrny, Dirk-Gunnar Welsch

Applying the recently developed formalism of quantum-state transformation at absorbing dielectric four-port devices [L.~Knöll, S.~Scheel, E.~Schmidt, D.-G.~Welsch, and A.V.~Chizhov, Phys. Rev. A {\bf 59}, 4716 (1999)], we calculate the quantum state of the outgoing modes of a two-mode squeezed vacuum transmitted through optical fibers of given extinction coe

Stefan Scheel, Dirk-Gunnar Welsch

A general theory of the interaction of the quantized electromagnetic field with atoms in the presence of dispersing and absorbing dielectric bodies of given Kramers--Kronig consistent permittivities is developed. It is based on a source-quantity representation of the electromagnetic field, in which the electromagnetic-field operators are expressed in terms o

Paul B. Slater

This paper has been superseded by quant-ph/0006009, &#34;Quantum State Estimation Using Non-separable Measurements&#34;.

E. Kolbe, K. Langanke, P. Vogel

We use the random phase approximation to describe the muon capture rate on ${}^{44}$Ca,${}^{48}$Ca, ${}^{56}$Fe, ${}^{90}$Zr, and ${}^{208}$Pb. With ${}^{40}$Ca as a test case, we show that the Continuum Random Phase Approximation (CRPA) and the standard RPA give essentially equivalent descriptions of the muon capture process. Using the standard RPA with the

B. V. Carlson, D. Hirata

We develop a complete Dirac-Hartree-Fock-Bogoliubov approximation to the ground state wave function and energy of finite nuclei. We apply it to spin-zero proton-proton and neutron-neutron pairing within the Dirac-Hartree-Bogoliubov approximation (we neglect the Fock term), using a zero-range approximation to the relativistic pairing tensor. We study the effe

A. Celani, M. Vergassola

A general link between geometry and intermittency in passive scalar turbulence is established. Intermittency is qualitatively traced back to events where tracer particles stay for anomalousy long times in degenerate geometries characterized by strong clustering. The quantitative counterpart is the existence of special functions of particle configurations whi

Arul Lakshminarayan, Nicholas R. Cerruti, Steven Tomsovic

The correlation between level velocities and eigenfunction intensities provides a new way of exploring phase space localization in quantized non-integrable systems. It can also serve as a measure of deviations from ergodicity due to quantum effects for typical observables. This paper relies on two well known paradigms of quantum chaos, the bakers map and the

Nicholas R. Cerruti, Arul Lakshminarayan, Julie H. Lefebvre, Steven Tomsovic

In a previous Letter [Phys. Rev. Lett. 77, 4158 (1996)], a new correlation measure was introduced that sensitively probes phase space localization properties of eigenstates. It is based on a system&#39;s response to varying an external parameter. The measure correlates level velocities with overlap intensities between the eigenstates and some localized state

J. Asch, F. Bentosela, P. Duclos, G. Nenciu

We study the quantum dynamics generated by $H^{SW}=-{d^2\over dx^2}+V-x$ with $V$ a real periodic function of weak regularity. We prove that the continuous spectrum of $H^{SW}$ is never empty, and furthermore that for $V$ small enough there are no bound states.

Omar Mustafa, Maen Odeh

The pseudoperturbative shifted - l expansion technique PSLET [5,20] is generalized for states with arbitrary number of nodal zeros. Interdimensional degeneracies, emerging from the isomorphism between angular momentum and dimensionality of the central force Schrodinger equation, are used to construct part of the D - dimensional spiked harmonic oscillator bou

Stavros Garoufalidis

The purpose of the present paper is to introduce and explore two surprises that arise when we apply a standard procedure to study the number of finite type invariants of 3-manifolds introduced independently by M. Goussarov and K. Habiro based on surgery on claspers, Y-graphs or clovers, \cite{Gu,Ha,GGP}. One surprise is that the upper bounds depend on a bit

Philippe Biane, Dan Voiculescu

We define a free probability analogue of the Wasserstein metric, which extends the classical one. In dimension one, we prove that the square of the Wasserstein distance to the semi-circle distribution is majorized by a modified free entropy quantity.

Sinan Unver

We give an Arakelov theoretic proof of the equality of conductor and discriminant for arithmetic surfaces over number fields. This was first proved by T. Saito for relative curves over discrete valuation rings.

Ieke Moerdijk, Janez Mrcun

We use foliations and connections on principal Lie groupoid bundles to prove various integrability results for Lie algebroids. In particular, we show, under quite general assumptions, that the semi-direct product associated to an infinitesimal action of one integrable Lie algebroid on another is integrable. This generalizes recent results of Dazord and Nisto

Metin Gurses

We define a class of two dimensional surfaces conformally related to minimal surfaces in flat three dimensional geometries. By the utility of the metrics of such surfaces we give a construction of the metrics of $2 N$ dimensional Ricci flat (pseudo-) Riemannian geometries.

Tetsuo Shibuya, Akira Yasuhara

A pass-move and a $#$-move are local moves on oriented links defined by L.H. Kauffman and H. Murakami respectively. Two links are self pass-equivalent (resp. self $#$-equivalent) if one can be deformed into the other by pass-moves (resp. $#$-moves), where non of them can occur between distinct components of the link. These relations are equivalence relations

Oleg Viro

On logarithmic paper some real algebraic curves look like smoothed broken lines. Moreover, the broken lines can be obtained as limits of those curves. The corresponding deformation can be viewed as a quantization, in which the broken line is a classical object and the curves are quantum. This generalizes to a new connection between algebraic geometry and the

Stefan Kebekus

Let X be a projective variety which is covered by a family of rational curves of minimal degree. The classic bend-and-break argument of Mori asserts that if x and y are two general points, then there are at most finitely many curves in that family which contain both x and y. In this work we shed some light on the question as to whether two sufficiently gener

A. Rida, T. Sami

We introduce a general method in order to construct the non chiral fusion rules which determine the operator content of the operator product algebra for rational conformal field theories. We are particularly interested in the models of the complementary D-like solutions of modular invariant partition functions with cyclic center Zn. We find that the non chir

Remo Garattini

We conjecture that the neutral black hole pair production is related to the vacuum fluctuation of pure gravity via the Casimir-like energy. A generalization of this process to a multi-black hole pair is considered. Implications on the foam-like structure of spacetime and on the cosmological constant are discussed.

Mirjam Cvetic, Paul Langacker

We investigate four-dimensional N=1 Type IIB orientifolds with continuous Wilson lines, and their T-dual realizations as orientifolds with moving branes. When continuous Wilson lines become discrete the gauge symmetry is enhanced and the T-dual orientifold corresponds to branes sitting at the orbifold fixed points. There is a field theoretic analog describin

N. Evans, M. Petrini

We study the 5 dimensional SUGRA AdS duals of N=4, N=2 and N=1 Super-Yang-Mills theories. To sequentially break the N=4 theory mass terms are introduced that correspond, via the duality, to scalar VEVs in the SUGRA. We determine the appropriate scalar potential and study solutions of the equations of motion that correspond to RG flows in the field theories.

S. L. Dubovsky, V. A. Rubakov, P. G. Tinyakov

In a brane (domain wall) scenario with an infinite extra dimension and localized gravity, bulk fermions and scalars often have bound states with zero 4-dimensional mass. In this way massless matter residing on the brane may be obtained. We consider what happens when one tries to introduce small, but non-vanishing mass to these matter fields. We find that the

Florin Constantinescu, Guenter Scharf

We give an explicit $L^2$-representation of chiral charged fermions using the Hardy-Lebesgue octant decomposition. In the &#34; pure&#34; case such a representation was already used by M. Sato in holonomic field theory. We study both &#34;pure&#34; and &#34; mixed&#34; cases. In the compact case we rigorously define unsmeared chiral charged fermion operators

Giampiero Esposito

When quantum fields are studied on manifolds with boundary, the corresponding one-loop quantum theory for bosonic gauge fields with linear covariant gauges needs the assignment of suitable boundary conditions for elliptic differential operators of Laplace type. There are however deep reasons to modify such a scheme and allow for pseudo-differential boundary-

D. Gomez-Ullate, A. Gonzalez-Lopez, M. A. Rodriguez

A model describing N particles on a line interacting pairwise via an elliptic function potential in the presence of an external field is partially solved in the quantum case in a totally algebraic way. As an example, the ground state and the lowest excitations are calculated explicitly for N=2.

Konstantin G. Zloshchastiev

Inspiring ourselves by the assumption that the notion of symmetry itself is insufficient to construct the consistent physics of the Desert (the so-called region of energies beyond the Standard Model) and some additional insights are needed, we suggests that high-energy theories must take into account the higher-order variations of fields. With this in mind w