Research archive
arXiv papers from September 1995
The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.
Lajos Diosi
We argue that the "reduced wave function", proposed recently [Phys.Rev.Lett. {\bf 75}, 2255 (1995)], contains conditional and restricted information on the reduced system. The concept of "reduced wave function" can thus not represent a relevant alternative to the common reduced dynamics methods.
Kenji Ikegami, Kei-ichi Kondo, Atsushi Nakamura
We propose to use a novel master Lagrangian for performing the bosonization of the $D$-dimensional massive Thirring model in $D=d+1 \ge 2$ dimensions. It is shown that our master Lagrangian is able to relate the previous interpolating Lagrangians each other which have been recently used to show the equivalence of the massive Thirring model in (2+1) dimension
Philip C. Argyres, Alfred D. Shapere
We determine the vacuum structure of N=2 supersymmetric QCD with fundamental quarks for gauge groups SO(n) and Sp(2n), extending prior results for SU(n). The solutions are all given in terms of families of hyperelliptic Riemann surfaces of genus equal to the rank of the gauge group. In the scale invariant cases, the solutions all have exact S-dualities which
Ahmed Hindawi, Burt A. Ovrut, Daniel Waldram
We discuss the general form of quadratic (1,1) supergravity in two dimensions, and show that this theory is equivalent to two scalar supermultiplets coupled to non-trivial supergravity. It is demonstrated that the theory possesses stable vacua with vanishing cosmological constant which spontaneously break supersymmetry.
M. J. Rozenberg, G. Kotliar, H. Kajueter
We study the transfer of spectral weight in the photoemission and optical spectra of strongly correlated electron systems. Within the LISA, that becomes exact in the limit of large lattice coordination, we consider and compare two models of correlated electrons, the Hubbard model and the periodic Anderson model. The results are discussed in regard of recent
Jan Ridky
The stochastic quantization of the fermion field is performed starting from Dirac equations. The statistical properties of stochastic terms in Langevin equations are described by explicit formulae of a Markov process. The interaction of the field is introduced as correlation of the stochastic terms. In the long time limit free fermions disappear and proper c
G. Fiorentini, B. Ricci
We extract information on the fluxes of Be and CNO neutrinos directly from solar neutrino experiments, with minimal assumptions about solar models. Next we compare these results with solar models, both standard and non standard ones. Finally we discuss the expectations for Borexino, both in the case of standard and non standard neutrinos.
J. H. Kung
Quadratic theory of gravity is a complicated constraint system. We investigate some consequences of treating quadratic terms perturbatively (higher derivative version of backreaction effects). This approach is shown to overcome some well known problems associated with higher derivative theories, i.e., the physical gravitational degree of freedom remains unch
- Integrability and Applications of the Exactly-Solvable Haldane-Shastry One-Dimensional Quantum Spin Chaincond-mat
Johan Cornelis Talstra
Recently, the one dimensional model of $N$ spins with $S=\frac{1}{2}$ on a circle, interacting with an exchange that falls off with the inverse square of the separation: $H_{\rm ISE} =\sum_{i\neq j} \frac{1}{[\frac{N}π \sin(\frac{i-j}{N}π)]^2}(\svec_i\cdot \svec_j-\frac{1}{4})$, or ISE-model, has received ample attention. Its special features include: relati
T. J. P. Penna, S. Moss de Oliveira
We succeeded in obtaining exact results of the bit-string model of biological aging for populations whose individuals breed only once. These results are in excellent agreement with those obtained through computer simulations. In addition, we obtain an expression for the minimum birth needed to avoid mutational meltdown.
Shailesh Chandrasekharan, Norman Christ
The QCD phase transition is studied on $16^3$ and $32^3 \times 4$ lattices both with and without quark loops. We introduce a new zero-flavor or quenched species of quark $\zeta$ and study the resulting chiral condensate, $\azbz$ as a function of the $\zeta$ mass, $m_\zeta$. By examining $\azbz$ for $10^{-10} \le m_\zeta \le 10$ we gain considerable informati
V. P. Akulov, V. D. Gershun
We proposed the construction of the differential calculus on the quantum group and its subgroup with the property of the natural reduction: the differential calculus on the quantum group $GL_q(2,C)$ has to contain the differential calculus on the quantum subgroup $SL_q(2,C)$ and quantum plane $C_q(2|0)$ (''quantum matrjoshka''). We found, that there are two
J. H. Knapen, R. F. Peletier, I. Shlosman, J. E. Beckman
High-resolution NIR and optical images are used to constrain a dynamical model of the circumnuclear star forming (SF) region in the barred galaxy M100 (=NGC 4321). Subarcsecond resolution allowed us to distinguish important morphological details which are easily misinterpreted when using images at lower resolution. Small leading arms observed in our K-band i
Amol S. Dighe, Michael Gronau, Jonathan L. Rosner
A class of amplitude relations for decays of $B$ mesons is discussed. Processes involving $\eta$ and $\eta'$ in the final state are shown to provide useful information about weak phases in some cases even in the presence of octet-singlet mixing in these states. Some of the relations are unaffected by first-order SU(3) breaking.
- A Nonperturbative Calculation of Basic Chiral QCD Parameters within Dynamical Equations Approach to QCD at Low Energieshep-ph
V. Gogohia, Gy. Kluge, M. Prisznyák
Basic chiral QCD parameters (the pion decay constant, the quark and gluon condensates, the dynamically generated quark mass, etc) as well as the vacuum energy density have been calculated from first principles within a recently proposed dynamical equations approach to QCD at low energies. The zero modes enhancement (ZME) model of quark confinement and dynami
S. Abachi
A study of the particle multiplicity between jets with large rapidity separation has been performed using the D{\O}detector at the Fermilab Tevatron $p\bar{p}$ Collider operating at $\sqrt{s}=1.8$ TeV. A significant excess of low-multiplicity events is observed above the expectation for color-exchange processes. The measured fractional excess is $1.07 \pm 0.
- Off-Diagonal Long-Range Order, Restricted Gauge Transformations, and Aharonov-Bohm Effect in Conductorsquant-ph
Murray Peshkin
The Hamiltonian describing a conductor surrounding an external magnetic field contains a nonvanishing vector potential in the volume accessible to the electrons and nuclei of which the conductor is made. That vector potential cannot be removed by a gauge transformation. Nevertheless, a macroscopic normal conductor can experience no Aharonov-Bohm effect. That
- Hydrodynamical analysis of single inclusive spectra and Bose-Einstein correlations for $Pb+Pb$ at 160 AGeVhep-ph
B. R. Schlei, U. Ornik, M. Plümer, D. Strottman
We present the first analysis of preliminary data for $Pb+Pb$ at 160 $AGeV$ using 3+1-dimensional relativistic hydrodynamics. We find excellent agreement with the rapidity spectra of negative hadrons and the correlation measurements. The data indicates a large amount of stopping; $65\%$ of the invariant energy of the collision is thermalized and $73\%$ of th
Manuel Drees, Madison
It is shown that in a large class of E(6) models, either an e+e- collider operating at $\rs \geq 1.5$ TeV must find a signal for the production of exotic leptons, or a collider operating at $\rs \geq 300$ GeV must find at least one light neutral Higgs boson with a large invisible branching ratio. The region of parameter space where neither of these signals i
S. Mrenna, C. -P. Yuan
We study the possibility of discovering or excluding a light top squark (stop) based on top quark decays in the t-tbar events produced at the Fermilab Tevatron. In particular, we consider the Minimal Supersymmetric Standard Model with the sparticle spectrum m_{chi^+_1}+m_b, M_W+m_{chi^0_1}+m_b > m_{stop} > m_{chi^0_1}+m_c, where chi^0_1 is the lightest neutr
Vivek Agrawal, T. K. Gaisser, Paolo Lipari, Todor Stanev
In this paper we extend an earlier calculation of the flux of atmospheric neutrinos to higher energy. The earlier calculation of the neutrino flux below 3 GeV has been used for calculation of the rate of contained neutrino interactions in deep underground detectors. The fluxes are needed up to neutrino energies of 10 TeV to calculate the expected rate of neu
James E. Hetrick
We digitally filter the Fourier modes of the link angles of an abelian lattice gauge field which produces the Fourier modes of a continuum $A_\mu(x)$ that exactly reproduces the lattice links through their definition as phases of finite parallel transport. The constructed interpolation is smooth ($C^\infty$), free from transition functions, and gauge equivar
E. Dagotto, T. M. Rice
One way of making the transition between the quasi-long range order in a chain of S=1/2 spins coupled antiferromagnetically and the true long range order that occurs in a plane, is by assembling chains to make ladders of increasing width. Surprisingly this crossover between one and two dimensions is not at all smooth. Ladders with an even number of legs have
Robert Friedman, John W. Morgan
We compare the deformation theory and the analytic structure of the Seiberg-Witten moduli spaces of a K\"ahler surface to the corresponding components of the Hilbert scheme, and show that they are isomorphic. Next we show how to compute the invariant in case the moduli space is smooth but not of the expected dimension, and apply this study to elliptic surfac
Robert M. Wald
We review the mathematically rigorous formulation of the quantum theory of a linear field propagating in a globally hyperbolic spacetime. This formulation is accomplished via the algebraic approach, which, in essence, simultaneously admits all states in all possible (unitarily inequivalent) Hilbert space constructions. The physically nonsingular states are r
A. Bianconi, M. Radici
The Glauber method is extensively used to describe the motion of a hadronic projectile in interaction with the surrounding nuclear medium. One of the main approximations consists in the linearization of the wave equation for the interacting particle. We have studied the consequences of such an assumption in the case of the $^{12}\mathrm{C(e,e}'\mathrm{p)}^{1
Thomas Waindzoch, Jochen Wambach
We study the unstable modes of the baryon number two hedgehog of the Skyrme model on a three dimensional spatial lattice. An expansion of the Skyrme Lagrangian around the hedgehog configuration provides the equations of motion for the fluctuation fields solvable numerically via a relaxation method. We find the negative energy modes and, by evolving the excit
Eliot Quataert, Pawan Kumar, Chi On Ao
We check the validity of the widely used classical apsidal motion formula as a function of orbital parameters, stellar structure, and stellar rotation rate by comparing dynamical calculations of the periastron advance with the static tidal formula. We find that the classical formula gives very accurate results when the periods of the low order quadrupole g,
Amitava Datta, E. A. Paschos, J. -M. Schwarz, M. N. Sinha Roy
The QCD corrections for the box diagrams are revisited for the case of a heavy top quark with $\mt = 174 \GeV$. We resolve first a longstanding discrepancy between two methods of calculation by showing that they give the same results when the threshold factors are treated correctly. Using this observation we refine our earlier results and derive formulae val
Michael B. Green, Michael Gutperle
The influence of world-sheet boundary condensates on the toroidal compactification of bosonic string theories is considered. At the special points in the moduli space at which the closed-string theory possesses an enhanced unbroken $G\times G$ symmetry (where $G$ is a semi-simple product of simply laced groups) a scalar boundary condensate parameterizes the
J. Bernabeu, D. Comelli, L. Lavoura, Joao P Silva
We investigate the effects of the new scalars in a two-Higgs-doublet model on the weak magnetic dipole moments of the fermions at the $Z$ peak. Proportionality of the Yukawa couplings to the fermion masses, and to $\tan{\beta}$, makes such effects more important for the third family, and potentially relevant. For the $\tau$ lepton, the new diagrams are suppr
C. Boros, Liang Zuo-tang, Meng Ta-chung
It is suggested that virtual gluon-clusters exist in nucleon, and that such colorless and colored objects manifest themselves in the small $x_B$ region of inelastic lepton-nucleon scattering processes. The relationship between the space-time properties of such clusters and the striking features observed in these scattering processes is discussed. A phase-spa
M. -Th. Huett, A. I. Milstein
The contribution of mesonic exchange currents to nuclear Compton scattering is investigated within the framework of a Fermi gas model of nuclear matter in the non-relativistic limit. The additional interaction between the nucleons is accounted for by including two- and three-body diagrams. As a test of this model, the enhancement constant $\kappa $ is calcul
- Theory for Superconducting Properties of the Cuprates: Doping Dependence of the Electronic Excitations and Shadow Statescond-mat
S. Grabowski, M. Langer, J. Schmalian, K. H. Bennemann
The superconducting phase of the 2D one-band Hubbard model is studied within the FLEX approximation and by using an Eliashberg theory. We investigate the doping dependence of $T_c$, of the gap function $\Delta ({\bf k},\omega)$ and of the effective pairing interaction. Thus we find that $T_c$ becomes maximal for $13 \; \%$ doping. In {\it overdoped} systems
Per Elmfors, David Persson, Bo-Sture Skagerstam
The thermal self-energy of an electron in a static uniform magnetic field $B$ is calculated to first order in the fine structure constant $\alpha $ and to all orders in $eB$. We use two methods, one based on the Furry picture and another based on Schwinger's proper-time method. As external states we consider relativistic Landau levels with special emphasis o
Philip R. Page
We introduce general selection rules arizing from flux-tube dynamics with non-relativistic and adiabatic quark motion, without employing model-dependent assumptions. Specifically, we indicate under which circumstances hybrids with an arbitrary degree of flux-tube excitation can disguise themselves by not decaying to S--wave states.
H. W. Grie\{ss}hammer
It is shown that in the modified axial gauge version of canonically quantized QCD$_{3+1}$ on a torus only nongeneric gauge field configurations allow for large gauge transformations. For the other configurations, the gauge is fixed completely. Such configurations carry nonzero total magnetic abelian fluxes, correspond to magnetic vortices parallel to the coo
Boris E. Stern
Individual gamma ray bursts (GRBs) have very diverse time behavior - from a single pulse to a long complex sequence of chaotic pulses of different timescales. I studied light curves of GRBs using data from the CGRO's BATSE experiment and found that the average post-peak time history for a sample of 460 bursts obeys an unique and simple analytical law: $I \si
Johannes Voit
I attempt to give a pedagogical overview of the progress which has occurred during the past decade in the description of one-dimensional correlated fermions. Fermi liquid theory based on a quasi-particle picture, breaks down in one dimension because of the Peierls divergence and because of charge-spin separation. It is replaced by a Luttinger liquid whose el
V. I. Man'ko
The theory of quantum propagator and time--dependent integrals of motion in quantum optics is reviewed as well as the properties of Wigner function, Q--function, and coherent state representation. Propagators and wave functions of a free particle, harmonic oscillator, and the oscillator with varying frequency are studied using time--dependent linear in posit
Ortwin Gerhard, Joseph Silk
We consider the possibility that the dark matter in the halos of galaxies may be in the form of clusters of \macho s within which are embedded cold, dense gas clouds. Microlensing experiments have found evidence that the Galactic halo contains up to half of its mass in the form of low-mass \macho s. A number of observational and dynamical arguments point to
R. Bates et al
In this paper we present a method for simulating the response of microstrip detectors to minimum ionizing particles, making use of a program for field calculation, a program for carrier drift and SPICE for circuit response. A knowledge of the electric field is essential for any further improvement of the program. A simple model involving EL2 levels in the me
R. Bates et al
This paper presents current noise characterization of circular pad Schottky barrier diodes with guard rings. The diodes were fabricated from undopped semi-insulating GaAs, SIU-GaAs, at the University of Glasgow. Current noise spectra were obtained for the detectors for two pad sizes, with reverse bias applied. Three measurements were also made on one of the
C. Bernard, T. Blum, C. DeTar, Steven Gottlieb
We improve the calculation of the equation of state for two flavor QCD by simulating on $N_t=6$ lattices at appropriate values of the couplings for the deconfinement/chiral symmetry restoration crossover. For $am_q=0.0125$ the energy density rises rapidly to approximately 1 ${\rm GeV/fm^3}$ just after the crossover($m_\pi/m_\rho\approx 0.4$ at this point). C
Per Berglund, Clifford V. Johnson, Shamit Kachru, Philippe Zaugg
A Lagrangian definition of a large family of (0,2) supersymmetric conformal field theories may be made by an appropriate gauge invariant combination of a gauged Wess-Zumino-Witten model, right-moving supersymmetry fermions, and left-moving current algebra fermions. Throughout this paper, use is made of the interplay between field theoretic and algebraic tech
Juan Carlos D'Olivo, Jose F. Nieves, Palash B. Pal
Due to their weak interactions, neutrinos can polarize a medium and acquire an induced charge. We consider the Cherenkov radiation emitted by neutrinos due to their effective electromagnetic interactions as they pass through a polarizable medium. The effect exists even for massless, chiral neutrinos, where no physics beyond the standard model needs to be ass
Hsiang-nan Li, Hoi-Lai Yu
We develop the perturbative QCD formalism for inclusive semileptonic $B$ meson decays, which includes Sudakov suppression from the resummation of large radiative corrections near the high end of charged lepton energy. Transverse degrees of freedom of partons are introduced to facilitate the factorization of $B$ meson decays. Ambiguities appearing in the quar
- Chiral Perturbation Theory for $\tau \to \rho \pi\nu_\tau$, $\tau \to K^* \pi \nu_\tau$, and $\tau \to \omega \pi \nu_\tau$hep-ph
Hooman Davoudiasl, Mark B. Wise
We use heavy vector meson $SU(2)_L \times SU(2)_R$ chiral perturbation theory to predict differential decay distributions for $\tau \rightarrow \rho \pi \nu_\tau$ and $\tau \rightarrow K^* \pi \nu_\tau$ in the kinematic region where $p_V \cdot p_\pi/m_V$ (here $V = \rho$ or $K^*$) is much smaller than the chiral symmetry breaking scale. Using the large numbe
Goetz Giese
We consider a one-dimensional "gas" of inelastically colliding particles where kinetic energy is dissipated by the excitation of vibrational degrees of freedom. In our model the coefficient of restitution is a stochastic quantity whose distribution can be calculated from an exact stochastic equation of motion. We investigate the equipartition propert
A. Kogut, A. J. Banday, C. L. Bennett, K. M. Gorski
We cross-correlate the COBE-DMR 2-year sky maps with spatial templates from long-wavelength radio surveys and the far-infrared COBE DIRBE maps. We place an upper limit on the spectral index of synchrotron radiation beta_{synch} < -2.9 between 408 MHz and 31.5 GHz. We obtain a statistically significant cross-correlation with the DIRBE maps whose dependence on
H. C. Rosu
A number of comments are provided on Rogers's model experiment to measure the circular Unruh vacuum noise by means of a hyperbolic Penning trap inside a microwave cavity. It is suggested that cylindrical Penning traps, being geometrically simpler, and controlled almost at the same level of accuracy as the hyperbolic trap, might be a better choice for such an
Salman Habib, Yuval Kluger, Emil Mottola, Juan Pablo Paz
The time evolution of a closed system of mean fields and fluctuations is Hamiltonian, with the canonical variables parameterizing the general time-dependent Gaussian density matrix of the system. Yet, the evolution manifests both quantum decoherence and apparent irreversibility of energy flow from the coherent mean fields to fluctuating quantum modes. Using
T. K. Kopeć, J. V. José
We study disordered Josephson junctions arrays with long-range interaction and charging effects. The model consists of two orthogonal sets of positionally disordered $N$ parallel filaments (or wires) Josephson coupled at each crossing and in the presence of a homogeneous and transverse magnetic field. The large charging energy (resulting from small self-capa
Ignatios Antoniadis, Pawel O. Mazur, Emil Mottola
The conformal factor of the spacetime metric becomes dynamical due to the trace anomaly of matter fields. Its dynamics is described by an effective action which we quantize by canonical methods on the Einstein universe $R\times S^3$. We find an infinite tower of discrete states which satisfy the constraints of quantum diffeomorphism invariance. These physica
Ignatios Antoniadis, Pawel O. Mazur, Emil Mottola
We analyze the constraints of general coordinate invariance for quantum theories possessing conformal symmetry in four dimensions. The character of these constraints simplifies enormously on the Einstein universe $R \times S^3$. The $SO(4,2)$ global conformal symmetry algebra of this space determines uniquely a finite shift in the Hamiltonian constraint from
O. I. Kartavtsev
Recent experiments on the laser-induced resonant annihilation provide a precise measurement of transition energies of antiprotonic helium atoms. Relativistic corrections of an order of $\alpha ^2$ to the pure Coulomb interaction will be taken into account in the theoretical description of energy spectra of antiprotonic helium atoms. The splitting of energy l
Claude Roiesnel
We study the U(2) lattice gauge theory in the pure gauge sector using the simplest action, with determinant and fundamental terms, having the naive continuum limit of SU(2)$\times$U(1). We determine part of the phase diagram of the model and find a first-order critical line which goes through the U(1) critical point. We show how to deduce both the order para
- The Baryon Fraction and Velocity--Temperature Relation in Galaxy Clusters : Models versus Observationsastro-ph
Lori M. Lubin, Renyue Cen, Neta A. Bahcall, Jeremiah P. Ostriker
The observed baryon fraction and velocity--temperature relation in clusters of galaxies are compared with hydrodynamic simulations in two cosmological models : standard (Omega = 1) and a low-density flat (Omega=0.45 and \lambda=0.55) CDM models, normalized to the COBE background fluctuations. The observed properties of clusters include the velocity dispersio
Joseph D. Romano, Charles G. Torre
The Hamiltonian structure of spacetimes with two commuting Killing vector fields is analyzed for the purpose of addressing the various problems of time that arise in canonical gravity. Two specific models are considered: (i) cylindrically symmetric spacetimes, and (ii) toroidally symmetric spacetimes, which respectively involve open and closed universe bound
H. Thomas Williams
A summary of the properties of the Wigner Clebsch-Gordan coefficients and isoscalar factors for the group SU3 in the SU2$\otimes$U1 decomposition is presented. The outer degeneracy problem is discussed in detail with a proof of a conjecture (Braunschweig's) which has been the basis of previous work on the SU3 coupling coefficients. Recursion relations obeyed
Scott Dodelson, Evalyn Gates, Albert Stebbins
We examine the cosmic microwave background power spectrum for adiabatic models with a massive neutrino component. We present the results of a detailed numerical evolution of cold + hot dark matter (CHDM) models and compare with the standard cold dark matter (CDM) spectrum. The difference is of order $5-10%$ for $400 < l < 1000 $ for currently popular CHDM mo
G J Chaitin
This condensed version of chao-dyn/9509010 will be the main hand-out for a course on algorithmic information theory to be given 22-29 May 1996 at the Rovaniemi Institute of Technology, Rovaniemi, Finland (see announcement at http://www.rotol.fi/ ).
J. R. Morris
A model of a straight superconducting global cosmic string is examined in a setting wherein the string supports a charge/current pulse described by a travelling wave along the string. Linearized field equations are obtained for fluctuations of the scalar and vector fields of the theory, and a set of approximate particular solutions are found for the case in
Takashi Nakatsukasa
Properties of octupole vibrations in rapidly rotating nuclei are discussed. Microscopic RPA calculations based on the cranked shell model are performed to investigate the interplay between rotation and vibrations. The ability of this model to describe the properties of collective vibrations built on the ground bands in rare-earth and actinide nuclei is demon
- On Modular Invariant Partition Functions of Conformal Field Theories with Logarithmic Operatorshep-th
Michael Flohr
We extend the definitions of characters and partition functions to the case of conformal field theories which contain operators with logarithmic correlation functions. As an example we consider the theories with central charge c = c(p,1) = 13-6(p+1/p), the ``border'' of the discrete minimal series. We show that there is a slightly generalized form of the pro
E. Dudas, S. Pokorski, C. A. Savoy
In supergravity with modular invariance and horizontal $U(1)_X$ gauge symmetry there is a relation between modular weights and $U(1)_X$ charges. The soft scalar masses are then strongly correlated with Yukawa matrices. The implications for FCNC are discussed.
O. Ragnisco, M. Bruschi
The integrability of a family of hamiltonian systems, describing in a particular case the motionof N ``peakons" (special solutions of the so-called Camassa-Holm equation) is established in the framework of the $r$-matrix approach, starting from its Lax representation. In the general case, the $r$-matrix is a dynamical one and has an interesting though compli
Ofer Aharony, Michael E. Peskin, Jacob Sonnenschein, Shimon Yankielowicz
We analyze the theory of softly broken supersymmetric $QCD$. Exotic behavior like spontaneously broken baryon number, massless composite fermions and Seiberg's duality seems to persist also in the presence of (small) soft supersymmetry breaking. We argue that certain, specially tailored, lattice simulations may be able to detect the novel phenomena. Most of
Michael Strube, Udo Hahn
A hybrid methodology for the resolution of text-level ellipsis is presented in this paper. It incorporates conceptual proximity criteria applied to ontologically well-engineered domain knowledge bases and an approach to centering based on functional topic/comment patterns. We state text grammatical predicates for ellipsis and then turn to the procedural aspe
V. Fisher, V. Bernshtam, H. Golten, Y. Maron
We present a semiempirical Gaunt factor for widely used Van Regemorter formula [Astrophys. J. 136, 906 (1962)] for the case of allowed transitions in atoms with the LS coupling scheme. Cross sections calculated using this Gaunt factor agree with measured cross sections to within the experimental error.
Yaw-Hwang Chen, Min-Tsung He, Su-Long Nyeo
We introduce an approach for calculating the quantum loop corrections in the $\phi^4$ theory. Differential regularization and background-field method are essential tools and are used to calculate the effective action of the theory to two-loop order. Our approach is considerably simpler than other known methods and can be readily extended to higher-loop calcu
Jens O. Andersen
Massless quantum electrodynamics is studied at high temperature and zero chemical potential. We compute the Debye screening mass to order $e^{4}$ and the free energy to order $e^{5}$} by an effective field theory approach, recently developed by Braaten and Nieto. Our results are in agreement with calculations done in resummed perturbation theory. This method
Martin Kraus, Udo Seifert, Reinhard Lipowsky
We theoretically study the behavior of vesicles filled with a liquid of higher density than the surrounding medium, a technique frequently used in experiments. In the presence of gravity, these vesicles sink to the bottom of the container, and eventually adhere even on non - attractive substrates. The strong size-dependence of the gravitational energy makes
- Critical behaviour of SU(2) lattice gauge theory. A complete analysis with the $\chi^2$-methodhep-lat
J. Engels, S. Mashkevich, T. Scheideler, G. Zinovjev
We determine the critical point and the ratios $\beta/\nu$ and $\gamma/\nu$ of critical exponents of the deconfinement transition in $SU(2)$ gauge theory by applying the $\chi^2$-method to Monte Carlo data of the modulus and the square of the Polyakov loop. With the same technique we find from the Binder cumulant $g_r$ its universal value at the critical poi
Chong-Xing Yue, Yu-Ping Kuang, Gong-Ru Lu
We estimate the correction to the Zbb-bar vertex arising from the exchanges of the sideways extended technicolor (ETC) boson and the flavor-diagonal ETC boson in the multiscale walking technicolor model. The obtained result is too large to explain the present data. However, if we introduce a new self- interaction for the top quark to induce the top quark con
Becca Asquith
The restrictions imposed on the strong force in the `non-commutative standard model' are examined. It is concluded that given the framework of non-commutative geometry and assuming the electroweak sector of the standard model many details of the strong force can be explained including its vectorial nature.
Sushkov Sergei
The renormalized stress-energy tensor $\langle T_{\mu\nu}\rangle$ of the quantized complex massless scalar field which obeys the automorphic condition in Misner space is obtained. It is shown that there exists the special value of the automorphic parameter for which $\langle T_{\mu\nu}\rangle$ is regular on the chronology horizon and, so, can not act as a pr
Nobuhiro Maekawa
We examine a dual theory of a Supersymmetric Standard Model(SSM) in terms of an $SU(3)_C$ gauge group. In this scenario, it is naturally understood that at least one quark (the top quark) should be heavy, i.e., almost the same order as the weak scale. Moreover, the supersymmetric Higgs mass parameter $\mu$ can naturally be expected to be small. This model au
Toshio Nakatsu, Kanehisa Takasaki
The exact solution of $N=2$ supersymmetric $SU(N)$ Yang-Mills theory is studied in the framework of the Whitham hierarchies. The solution is identified with a homogeneous solution of a Whitham hierarchy. This integrable hierarchy (Whitham-Toda hierarchy) describes modulation of a quasi-periodic solution of the (generalized) Toda lattice hierarchy associated
Lev Kofman, Anatoly Klypin, Dmitri Pogosyan, J. Patrick Henry
We discuss the structure of clusters in a class of flat cosmological models with the fraction of mass \Omega_{CDM} ~0.8 in cold dark matter, and the rest in hot dark matter in the form of massive neutrinos. We consider such Cold+Hot Dark Matter (CHDM) models with one, two or three massive neutrinos, with total mass ~4.6eV. Neutrinos of such low mass cannot c
Zhen Cao, Rudolph C. Hwa
The evolution of cooperative behaviour is studied in the deterministic version of the Prisoners' Dilemma on a two-dimensional lattice. The payoff parameter is set at the critical region $1.8 < b < 2.0$ , where clusters of cooperators are formed in all spatial sizes. Using the factorial moments developed in particle and nuclear physics for the study of phase
Murray Gell-Mann, James B. Hartle
We introduce a condition for the strong decoherence of a set of alternative histories of a closed quantum-mechanical system such as the universe. The condition applies, for a pure initial state, to sets of homogeneous histories that are chains of projections, generally branch-dependent. Strong decoherence implies the consistency of probability sum rules but
V. Le Brun, J. Bergeron, P. Boisse
We present results from a spectroscopic and imaging survey of galaxies in the fields of quasars from the HST Quasar Absorption Line Key Project. The aim of this survey is to identify galaxies within 3.5' from the quasar sightline, to a limiting r-band magnitude mr = 22.5. The data are then compared to the HST homogeneous sample of Lyman-alpha-only absorb
E. Martinec, N. Warner
After the work of Seiberg and Witten, it has been seen that the dynamics of N=2 Yang-Mills theory is governed by a Riemann surface $\Sigma$. In particular, the integral of a special differential $\lambda_{SW}$ over (a subset of) the periods of $\Sigma$ gives the mass formula for BPS-saturated states. We show that, for each simple group $G$, the Riemann surfa
A. M. S. Macedo
A Brownian motion model is proposed to study parametric correlations in the transmission eigenvalues of open ballistic cavities. We find interesting universal properties when the eigenvalues are rescaled at the hard edge of the spectrum. We derive a formula for the power spectrum of the fluctuations of transport observables as a response to an external adiab
A. Ceresole, R. D'Auria, S. Ferrara
We report on the formulation of $N=2$ $D=4$ supergravity coupled to $n_V$ abelian vector multiplets in presence of electric and magnetic charges. General formulae for the (moduli dependent) electric and magnetic charges for the $n_V+1$ gauge fields are given which reflect the symplectic structure of the underlying special geometry. The specification to Type
Chris L. Fryer, Willy Benz, Marc Herant
We present an extensive study of accretion onto neutron stars in which the velocity of the neutron star and structure of the surrounding medium is such that the Bondi-Hoyle accretion exceeds .001 Msun/y. For most cases, hypercritical accretion due to rapid neutrino cooling allows the neutron star to accrete above the Bondi-Hoyle rate as previously pointed ou
Bumsig Kim
Using the Kontsevich's moduli space of stable maps, we define the equivariant quantum cohomology for generalized flag varieties and make a rigorous computation of quantum cohomology of flag varieties.
Dirk H. Rischke, Miklos Gyulassy
The width $\Delta T$ of the deconfinement transition region is shown to influence strongly the flow structure in the (Landau-) hydrodynamical expansion of a quark-gluon plasma. For a sharp first order transition ($\Delta T=0$) the mixed phase is rather long-lived, with a lifetime that has a maximum when the initial energy density is at the phase boundary bet
The NMC Collaboration
The proton and deuteron structure functions F2p and F2d were measured in the kinematic range 0.006<x<0.6 and 0.5<Q^2<75 GeV^2, by inclusive deep inelastic muon scattering at 90, 120, 200 and 280 GeV. The measurements are in good agreement with earlier high precision results. The present and earlier results together have been parametrised to give descriptions
Niall D. Whelan
Diffraction, in the context of semiclassical mechanics, describes the manner in which quantum mechanics smooths over discontinuities in the classical mechanics. An important example is a billiard with sharp corners; its semiclassical quantisation requires the inclusion of diffractive periodic orbits in addition to classical periodic orbits. In this paper we
Renu Malhotra
The Solar system beyond Neptune is believed to house a population of small primordial bodies left over from the planet formation process. The region up to heliocentric distance $\sim 50 AU$ (a.k.a. the Kuiper Belt) may be the source of the observed short period comets. In this region, the phase space structure near orbital resonances with Neptune is of speci
J. W. Moffat, I. Yu. Sokolov
In the weak field approximation, the nonsymmetric gravitational theory (NGT) has, in addition to the Newtonian gravitational potential, a Yukawa-like potential produced by the exchange of a spin $1^+$ boson between fermions. If the range $r_0=\mu^{-1}$ is $25$ kpc, then this additional potential due to the interaction with matter in the halos of galaxies can
A. B. Arbuzov, E. A. Kuraev, N. P. Merenkov, L. Trentadue
Radiative corrections due to the production of virtual as well as real soft and hard pairs in small-angle Bhabha scattering are calculated analytically. Both the collinear and the semi-collinear kinematical regions of hard pair production are considered. The calculation, within the leading and next-to-leading logarithmic approximation, provides an accuracy o
R. J. Radtke, V. N. Kostur, K. Levin
Recent measurements of the London penetration depth tensor in the cuprates find a weak temperature dependence along the c-direction which is seemingly inconsistent with evidence for d-wave pairing deduced from in-plane measurements. We demonstrate in this paper that these disparate results are not in contradiction, but can be explained within a theory based
Rodney Price, S. Das Sarma
We present the results of a variational Monte Carlo calculation of the exchange-correlation energy for a spin-polarized two-dimensional electron gas in a perpendicular magnetic field. These energies are a necessary input to the recently developed current-density functional theory. Landau-level mixing is included in a variational manner, which gives the energ
C. Michael
We present the lattice gauge theory approach to evaluating non-perturbative hadronic interactions from first principles. We discuss applications to glueballs, inter-quark potentials, the running coupling constant, the light hadron spectrum and the pseudoscalar decay constant $f_P$.
E. E. Fenimore, R. W. Klebesadel, J. G. Laros
The March 5th, 1979 gamma-ray transient has long been thought to be fundamentally different from the classic gamma-ray bursts (GRBs). It had recurrences, pulsations, and a soft spectral component unlike classic GRBs. With the exception of the soft component reported from the Konus experiment, the unusual characteristics of March 5th were detectable main peak
- Loop calculations in quantum-mechanical non-linear sigma models sigma models with fermions and applications to anomalieshep-th
Jan de Boer, Bas Peeters, Kostas Skenderis, Peter van Nieuwenhuizen
We construct the path integral for one-dimensional non-linear sigma models, starting from a given Hamiltonian operator and states in a Hilbert space. By explicit evaluation of the discretized propagators and vertices we find the correct Feynman rules which differ from those often assumed. These rules, which we previously derived in bosonic systems \cite{pape
Yu. A. Simonov
Dyonic classical solutions of $SU(2)$ gluodynamics are discussed. Exact form of dyonic solutions in different gauges is presented and the nontrivial problem of composition of the dilute gas of dyons is settled. Classical interaction between (anti)dyons is considered both analytically and numerically. Confinement in the dyonic gas is discussed in connection w