May 1992 arXiv papers — page 3

J C Romao, C A Santos, J W F Valle

We refute the claims made by Chaichian and Smilga in a recent paper in Phys Rev Letters on the impossibility of spontaneous R Parity breaking. Apart from explaining their error we summarize the results of a more detailed work that demonstrates explicitly that R parity can break spontaneously at a scale anywhere in the range 10 GeV to 1 Tev in a simple extens

Alberto Bressan, Benedetto Piccoli

Aim of this paper is to develop a new technique, based on the Baire category theorem, in order to establish the closure of reachable sets and the existence of optimal trajectories for control systems, without the usual convexity assumptions. The bang-bang property is proved for a new class of ``concave" multifunctions, characterized by the existence of s

A. V. Balatsky

The 3D state of strongly correlated electrons is proposed, which in the external magnetic field $\vec B$ exhibits the fractional quantum Hall effect, with the zero temperature conductivity tensor $σ_{ij} = (e^2/h)(1/m) \sum_k ε_{ijk} B^k/\mid \vec B\mid $. The analog of Landau and Laughlin states in 3D are given using quaternion coordinates as generalization

Wei Chen, Mikhail Dobroliubov, Gordon Semenoff

We argue that the \zn phases of hot gauge theories cannot be realized as a real system with an Hermitean density matrix.

Gabriel Lopes Cardoso, Burt A. Ovrut

We discuss the complete set of one-loop triangle graphs involving the Yang-Mills gauge connection, the \Kahler\ connection and the $σ$-model coordinate connection in the effective field theory of $(2,2)$ symmetric $Z_N$ orbifolds. That is, we discuss pure gauge, pure \Kahler\ and pure $σ$-model coordinate anomalies as well as the mixed anomalies, such as \Ka

John C. Baez

In Rovelli and Smolin's loop representation of nonperturbative quantum gravity in 4 dimensions, there is a space of solutions to the Hamiltonian constraint having as a basis isotopy classes of links in R^3. The physically correct inner product on this space of states is not yet known, or in other words, the *-algebra structure of the algebra of observabl

Markus A. Luty

We consider the question of vacuum alignment in the recently proposed "composite technicolor" (CTC) models. In order for these models to work, an "ultrafermion" condensate must align in a particular way, driven by the competition between ultrafermion masses and "flavor" gauge boson exchange. We show that for ultrafermion masses large

Jerome P. Gauntlett

In bosonic field theories the low-energy scattering of solitons that saturate Bogomol'nyi-type bounds can be approximated as geodesic motion on the moduli space of static solutions. In this paper we consider the analogous issue within the context of supersymmetric field theories. We focus our study on a class of $N=2$ non-linear sigma models in $d=2+1$ b

Matthew J. Strassler

In this paper the connection between standard perturbation theory techniques and the new Bern-Kosower calculational rules for gauge theory is clarified. For one-loop effective actions of scalars, Dirac spinors, and vector bosons in a background gauge field, Bern-Kosower-type rules are derived without the use of either string theory or Feynman diagrams. The e

Raman Sundrum

A realistic technicolor model is presented with the dynamics below $150$ TeV treated explicitly. Electroweak symmetry is broken by the condensates of a `minimal' doublet of technifermions. The new feature of the model is that the the third generation quarks are unified with the technifermions into multiplets of a walking gauge force down to a scale of $1

D. P. Clougherty, W. Kohn

We present an exact solution of a 1D model: a particle of incident energy $E$ colliding with a target which is a 1D harmonic ``solid slab'' with $N$ atoms in its ground state; the Hilbert space of the target is restricted to the ($N+1$) states with zero or one phonon present. For the case of a short range interaction, $V(z)$, between the particle and

J. Greensite

Following the reasoning of Claudson and Halpern, it is shown that "fifth-time" stabilized quantum gravity is equivalent to Langevin evolution (i.e. stochastic quantization) between fixed non-singular, but otherwise arbitrary, initial and final states. The simple restriction to a fixed final state at $t_5 \rightarrow \infty$ is sufficient to stabilize

Glenn Barnich, Marc Henneaux

It is shown that the local completeness condition introduced in the analysis of the locality of the gauge fixed action in the antifield formalism plays also a key role in the proof of unitarity.

George A. Willis

It is shown how to construct, given a Banach space which does not have the approximation property, another Banach space which does not have the approximation property but which does have the compact approximation property.

Kiwoon Choi, David B. Kaplan, Ann E. Nelson

We suggest here that CP is a discrete {\it gauge} symmetry, and is therefore not violated by quantum gravity. We show that four dimensional CP can arise as a discrete gauge symmetry in theories with dimensional compactification, if the original number of Minkowski dimensions equals $8k+1$, $8k+2$ or $8k+3$, and if there are certain restrictions on the gauge

Heinz König, K. A. Peterson

We present cross sections for the production of the lightest supersymmetric particle as a neutralino state in the minimal supersymmetric standard model at electron-photon colliders. The lightest supersymmetric particle mass is taken at a value of 30 GeV which is slightly higher than its lowest experimental bound of 20 GeV, and the masses of the scalar electr

Sergio Caracciolo, Robert G. Edwards, Andrea Pelissetto, Alan D. Sokal

We study a class of Monte Carlo algorithms for the nonlinear $σ$-model, based on a Wolff-type embedding of Ising spins into the target manifold $M$. We argue heuristically that, at least for an asymptotically free model, such an algorithm can have dynamic critical exponent $z \ll 2$ only if the embedding is based on an (involutive) isometry of $M$ whose fixe

J. I. Katz

I present a model for acceleration of protons by the second-order Fermi process acting on randomly scrambled magnetic flux arches above an accretion disc. The accelerated protons collide with thermal protons in the disc, producing degraded energetic protons, charged and neutral pions, and neutrons. The pions produce gamma-rays by spontaneous decay of $π^0$ a

Emili Bifet

One of the aims of this paper is to better explain the philosophy behind the computations in [E.Bifet, C.De Concini,C.Procesi Cohomology of Regular Embeddings ] and to place them in a wider conceptual setting. Another aim of the paper is to outline in the last section an ``equivariant'' approach to some key results in the theory of toric varieties. T

Robert W. Berger

There is a conjecture, that the torsionfreeness of the module of differentials in a point of an algebraic or algebroid curve should imply that the curve is non singular at that point. A report on the main results is given.

Wolfgang Bock, Asit K. De, Christoph Frick, Jiri Jersák

We study by numerical simulation a lattice Yukawa model with naive fermions at intermediate values of the Yukawa coupling $y$ when the nearest neighbour coupling $\kp$ of the scalar field $Φ$ is very weakly ferromagnetic ($\kp \approx 0$) or even antiferromagnetic ($κ< 0$) and the nonvanishing value of $\vev$ is generated by the Yukawa interaction. The renor

Shiwei Zhang, M. H. Kalos

We propose a bilinear sampling algorithm in Green's function Monte Carlo for expectation values of operators that do not commute with the Hamiltonian and for differences between eigenvalues of different Hamiltonians. The integral representations of the Schroedinger equations are transformed into two equations whose solution has the form $\psi_a(x) t(x,y) \ps

Maximilian Kreuzer, Harald Skarke

We use a recent classification of non-degenerate quasihomogeneous polynomials to construct all Landau-Ginzburg (LG) potentials for N=2 superconformal field theories with c=9 and calculate the corresponding Hodge numbers. Surprisingly, the resulting spectra are less symmetric than the existing incomplete results. It turns out that models belonging to the larg

T. Hanawa, R. Matsumoto, K. Shibata

The effect of the magnetic skew on the Parker instability is investigated by means of the linear stability analysis for a gravitationally stratified gas layer permeated by a horizontal magnetic field. When the magnetic field is skewed (i.e., the field line direction is a function of the height), the wavelength of the most unstable mode is $ λ\; \sim \; 10 H

Donald E. Knuth

The author advocates two specific mathematical notations from his popular course and joint textbook, &#34;Concrete Mathematics&#34;. The first of these, extending an idea of Iverson, is the notation &#34;[P]&#34; for the function which is 1 when the Boolean condition P is true and 0 otherwise. This notation can encourage and clarify the use of characteristic

Greg Hjorth

When the second uniform indiscernible is $\aleph_{2}$, the Martin-Solovay tree only constructs countably many reals; this resolves a number of open questions in descriptive set theory.

O. Ogievetsky, B. Zumino

The nonlinear reality structure of the derivatives and the differentials for the euclidean q-spaces are found. A real Laplacian is constructed and reality properties of the exterior derivative are given.

H. Awata, Y. Yamada

We analyze the properties of the q-vertex operators of U_q(sl(2)^) introduced by Frenkel and Reshetikhin. As the condition for the null vector decoupling, we derive the existence condition of the q-vertex operators ( the fusion rules ).

Vidyut Jain, Oleg Ogievetsky

The expressions for the $\hat{R}$--matrices for the quantum groups SO$_{q^2}$(5) and SO$_q$(6) in terms of the $\hat{R}$--matrices for Sp$_q$(2) and SL$_q$(4) are found, and the local isomorphisms of the corresponding quantum groups are established.

Herbert Neuberger

This is a slightly extended version of the talk delivered at the Topical Workshop ``Non perturbative aspects of chiral gauge theories&#39;&#39;, Accademia Nazionale dei Lincei, Roma, 9-11 March, 1992. Abstract: The Higgs mass in the minimal standard model is bounded by triviality and vacuum stability in the range 50--100 $GeV$ to 700--900 $GeV$. Recent resul

Koichi Funakubo, Taro Kashiwa

Discussions are made on the structures of chirally invariant lattice actions without any restriction of hermiticity. With the help of the Ward-Takahashi identity a general conclusion can be derived that there must be species doublers in any chirally invariant model provided that the model is chosen as well-regularized, that is, there is no singularity in the

Ulli Wolff

The CP^3 spin model is simulated at large correlation lengths in two dimensions. An overrelaxation algorithm is employed which yields reduced critical slowing down with dynamical exponents z around unity. We compare our results with recent multigrid data on the massgap m and the spin susceptibility and confirm the absence of asymptotic scaling. As a new resu

Leon Balents, Mehran Kardar

We consider a model of a reconstructed crystal surface, first considered by Villain and Vilfan (Europhys. Lett. 12, p. 523 (1990) and Surf. Sci. 257, p. 368 (1991)) for the gold (110) surface, in which roughening occurs via the formation of anisotropic steps traversing the entire length of the crystal. The model is studied by a mapping to a spin--1/2 Fermion

Antti-Pekka Jauho, Henrik Smith

The Coulomb contribution to the temperature-dependent rate of momentum transfer, $1/τ_D$, between two electron systems in parallel layers is determined by setting up two coupled Boltzmann equations, with the boundary condition that no current flows in the layer where an induced voltage is measured. The effective Coulomb interaction between the layers is dete

Valerio Faraoni

We apply Perlick&#39;s (1990a) rigorous formulation of the Fermat principle in arbitrary spacetimes to prove the correctness of the description of gravitational lensing by gravitational waves, given in the literature using the scalar and vector formalisms. We obtain an expression for the time delay due to such nonstationary lenses; the advantage over previou