526 research outputs found
Exclusion statistics for non-abelian quantum Hall states
We determine the exclusion statistics properties of the fundamental edge
quasi-particles over a specific \nu=\half non-abelian quantum Hall state
known as the pfaffian. The fundamental excitations are the edge electrons of
charge and the edge quasi-holes of charge . We explicitly
determine thermodynamic distribution functions and establish a duality which
generalizes the duality for fractional exclusion statistics in the sense of
Haldane.Comment: LaTeX, 4 pages, no figures; results for 1/q pfaffian adde
Comment on the paper ``The universal chiral partition function for exclusion statistics''
I comment on the paper hep-th/9808013 by A. Berkovich and B.M. McCoy.Comment: 1 page, revtex, original comment replaced by brief statemen
Supersymmetric Scattering in Two Dimensions
We briefly review results on two-dimensional supersymmetric quantum field
theories that exhibit factorizable particle scattering. Our particular focus is
on a series of supersymmetric theories, for which exact -matrices
have been obtained. A Thermodynamic Bethe Ansatz (TBA) analysis for these
theories has confirmed the validity of the proposed -matrices and has
pointed at an interesting `folding' relation with a series of
supersymmetric theories.Comment: 3 pages, wstwocl.sty, epsfig.sty, talk delivered at the HEP95
Conference of the EPS, Brussels, July/August 199
A form factor approach to finite temperature correlation functions in CFT
The excitation spectrum of specific conformal field theories (CFT) with
central charge can be described in terms of quasi-particles with charges
and fractional statistics properties. Using the language of Jack
polynomials, we compute form factors of the charge density operator in these
CFTs. We study a form factor expansion for the finite temperature
density-density correlation function, and find that it shows a quick
convergence to the exact result. The low-temperature behavior is recovered from
a form factor with particles, while the high-temperature limit is
recovered from states containing no more than 3 particles.Comment: 15 pp, 6 fi
The SU(n)_1 WZW Models: Spinon Decomposition and Yangian Structure
We present a `spinon formulation' of the Wess-Zumino-Witten models.
Central to this approach are a set of massless quasi-particles, called
`spinons', which transform in the representation of and
carry fractional statistics of angle . Multi-spinon states are
grouped into irreducible representations of the yangian . We give
explicit results for the content of these yangian representations and
present -spinon cuts of the WZW character formulas. As a by-product, we
obtain closed expressions for characters of the Haldane-Shastry spin
chains.Comment: 38 pages, LaTeX, no figure
On the quasiparticle description of c=1 CFTs
We show that the description of Conformal Field Theory in terms of
quasiparticles satisfying fractional statistics can be obtained from the
sine-Gordon model with a chemical potential , in the limit where .
These quasiparticles are related to the excitations of the Calogero-Sutherland
(CS) model. We provide a direct calculation of their 2-particle S-matrix using
Korepin's method. We also reconsider the computation of the CS S-matrix in
terms of particles with fractional charge
Supersymmetry, lattice fermions, independence complexes and cohomology theory
We analyze the quantum ground state structure of a specific model of
itinerant, strongly interacting lattice fermions. The interactions are tuned to
make the model supersymmetric. Due to this, quantum ground states are in
one-to-one correspondence with cohomology classes of the so-called independence
complex of the lattice. Our main result is a complete description of the
cohomology, and thereby of the quantum ground states, for a two-dimensional
square lattice with periodic boundary conditions. Our work builds on results by
J. Jonsson, who determined the Euler characteristic (Witten index) via a
correspondence with rhombus tilings of the plane. We prove a theorem, first
conjectured by P. Fendley, which relates dimensions of the cohomology at grade
n to the number of rhombus tilings with n rhombi.Comment: 40 pages, 28 figure
Non-abelian quantum Hall states - exclusion statistics, K-matrices and duality
We study excitations in edge theories for non-abelian quantum Hall states,
focussing on the spin polarized states proposed by Read and Rezayi and on the
spin singlet states proposed by two of the authors. By studying the exclusion
statistics properties of edge-electrons and edge-quasiholes, we arrive at a
novel K-matrix structure. Interestingly, the duality between the electron and
quasihole sectors links the pseudoparticles that are characteristic for
non-abelian statistics with composite particles that are associated to the
`pairing physics' of the non-abelian quantum Hall states.Comment: LaTeX2e, 40 page
Quantum phases of supersymmetric lattice models
We review recent results on lattice models for spin-less fermions with strong
repulsive interactions. A judicious tuning of kinetic and interaction terms
leads to a model possessing supersymmetry. In the 1D case, this model displays
critical behavior described by superconformal field theory. On 2D lattices we
generically find superfrustration, characterized by an extensive ground state
entropy. For certain 2D lattices analytical results on the ground state
structure reveal yet another quantum phase, which we tentatively call
'supertopological'.Comment: 5 pages, 1 figure, 1 table, contribution to the proceedings of the
XVI International Congress on Mathematical Physics (2009) in Prague, Czeck
Republi
Black Hole Evaporation and Quantum Gravity
In this note we consider some consequences of quantum gravity on the process
of black hole evaporation. In particular, we will explain the suggestion by 't
Hooft that quantum gravitational interactions effectively exclude simultaneous
measurements of the Hawking radiation and of the matter falling into the black
hole. The complementarity of these measurements is supported by the fact that
the commutators between the corresponding observables can be shown to grow
uncontrollably large. The only assumption that is needed to obtain this result
is that the creation and annihilation modes of the in-falling and out-going
matter act in the same Hilbert space. We further illustrate this phenomenon in
the context of two-dimensional dilaton gravity.Comment: 28 pages, LaTex, uses epsf.tex, CERN-TH.7142/94, PUPT-144
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