500 research outputs found
A Coherent State Path Integral for Anyons
We derive an coherent state path integral formula for a system of
two one-dimensional anyons in a harmonic potential. By a change of variables we
transform this integral into a coherent states path integral for a harmonic
oscillator with a shifted energy. The shift is the same as the one obtained for
anyons by other methods. We justify the procedure by showing that the change of
variables corresponds to a version of the Holstein-Primakoff
transformation.Comment: Latex 6 pages, USITP-94-1
The QCD Trace Anomaly as a Vacuum Effect (The vacuum is a medium is the message!)
We use arguments taken from the electrodynamics of media to deduce the QCD
trace anomaly from the expression for the vacuum energy in the presence of an
external color magnetic field.Comment: 18 pages, USITP 94-1
Discretization of the Superparticle Path Integral
Requiring that the path integral has the global symmetries of the classical
action and obeys the natural composition property of path integrals, and also
that the discretized action has the correct naive continuum limit, we find a
viable discretization of the (D=3,N=2) superparticle action.Comment: 10 page
The Quantum Geometry of N=(2,2) Non-Linear Sigma-Models
We consider a general N=(2,2) non-linear sigma-model in (2,2) superspace.
Depending on the details of the complex structures involved, an off-shell
description can be given in terms of chiral, twisted chiral and semi-chiral
superfields. Using superspace techniques, we derive the conditions the
potential has to satisfy in order to be ultra-violet finite at one loop. We pay
particular attention to the effects due to the presence of semi-chiral
superfields. A complete description of N=(2,2) strings follows from this.Comment: 9 pages, Late
The influence of the Hall force on the vortex dynamics in type II superconductors
The effect of the Hall force on the pinning of vortices in type II
superconductors is considered. A field theoretic formulation of the pinning
problem allows a non-perturbative treatment of the influence of quenched
disorder. A self-consistent theory is constructed using the diagrammatic
functional method for the effective action, and an expression for the pinning
force for independent vortices as well as vortex lattices is obtained. We find
that the pinning force for a single vortex is suppressed by the Hall force at
low temperatures while it is increased at high temperatures. The effect of the
Hall force is more pronounced on a single vortex than on a vortex lattice. The
results of the self-consistent theory are shown to be in good agreement with
numerical simulations.Comment: 9 pages, 4 figures, published in Physical Review
Global Anomalies and Anyons in 1+1 Dimensions
We consider the analog in one spatial dimension of the Bose-Fermi
transmutation for planar systems. A quantum mechanical system of a spin 1/2
particle coupled to an abelian gauge field, which is classically invariant
under gauge transformations and charge conjugation is studied. It is found that
unless the flux enclosed by the particle orbits is quantized, and the spin
takes a value , at least one of the two symmetries would be anomalous.
Thus, charge conjugation invariance and the existence of abelian instantons
simultaneously force the particles to be either bosons or fermions, but not
anyons.Comment: Changed title. To be published in Physics Letters
The Polyakov action on the supertorus
A consistent method for obtaining a well-defined Polyakov action on the
supertorus is presented. This method uses the covariantization of derivative
operators and enables us to construct a Polyakov action which is globally
defined.Comment: 15 pages LaTe
The N=4 string is the same as the N=2 string
We redo the quantization of the N=4 string, taking into account the
reducibility of the constraints. The result is equivalent to the N=2 string,
with critical dimension D=4 and signature (++--). The N=4 formulation has
several advantages: the sigma-model field equations are implied classically,
rather than by quantum/beta-function calculations; self-duality/chirality is
one of the super-Virasoro constraints; SO(2,2) covariance is manifest. This
reveals that the theory includes fermions, and is apparently spacetime
supersymmetric.Comment: 7 pg (uuencoded dvi file; otherwise same as original
Hyperkahler sigma models on cotangent bundles of Hermitian symmetric spaces using projective superspace
Kahler manifolds have a natural hyperkahler structure associated with (part
of) their cotangent bundles. Using projective superspace, we construct
four-dimensional N = 2 models on the tangent bundles of some classical
Hermitian symmetric spaces (specifically, the four regular series of
irreducible compact symmetric Kahler manifolds, and their non-compact
versions). A further dualization yields the Kahler potential for the
hyperkahler metric on the cotangent bundle.Comment: 47 pages, typos corrected, version accepted by JHE
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