6,693 research outputs found
Hierarchy wave functions--from conformal correlators to Tao-Thouless states
Laughlin's wave functions, describing the fractional quantum Hall effect at
filling factors , can be obtained as correlation functions in
conformal field theory, and recently this construction was extended to Jain's
composite fermion wave functions at filling factors . Here we
generalize this latter construction and present ground state wave functions for
all quantum Hall hierarchy states that are obtained by successive condensation
of quasielectrons (as opposed to quasiholes) in the original hierarchy
construction. By considering these wave functions on a cylinder, we show that
they approach the exact ground states, the Tao-Thouless states, when the
cylinder becomes thin. We also present wave functions for the multi-hole
states, make the connection to Wen's general classification of abelian quantum
Hall fluids, and discuss whether the fractional statistics of the
quasiparticles can be analytically determined. Finally we discuss to what
extent our wave functions can be described in the language of composite
fermions.Comment: 9 page
Exclusion Statistics in a trapped two-dimensional Bose gas
We study the statistical mechanics of a two-dimensional gas with a repulsive
delta function interaction, using a mean field approximation. By a direct
counting of states we establish that this model obeys exclusion statistics and
is equivalent to an ideal exclusion statistics gas.Comment: 3 pages; minor changes in notation; typos correcte
Jain States in a Matrix Theory of the Quantum Hall Effect
The U(N) Maxwell-Chern-Simons matrix gauge theory is proposed as an extension
of Susskind's noncommutative approach. The theory describes D0-branes,
nonrelativistic particles with matrix coordinates and gauge symmetry, that
realize a matrix generalization of the quantum Hall effect. Matrix ground
states obtained by suitable projections of higher Landau levels are found to be
in one-to-one correspondence with the expected Laughlin and Jain hierarchical
states. The Jain composite-fermion construction follows by gauge invariance via
the Gauss law constraint. In the limit of commuting, ``normal'' matrices the
theory reduces to eigenvalue coordinates that describe realistic electrons with
Calogero interaction. The Maxwell-Chern-Simons matrix theory improves earlier
noncommutative approaches and could provide another effective theory of the
fractional Hall effect.Comment: 35 pages, 3 figure
Real Time Correlators in Hot (2+1)d QCD
We use dimensional reduction techniques to relate real time finite T
correlation functions in (2+1) dimensional QCD to bound state parameters in a
generalized 't Hooft model with an infinite number of heavy quark and adjoint
scalar fields. While static susceptibilities and correlation functions of the
DeTar type can be calculated using only the light (static) gluonic modes, the
dynamical correlators require the inclusion of the heavy modes. In particular
we demonstrate that the leading T perturbative result can be understood in
terms of the bound states of the 2d model and that consistency requires bound
state trajectories composed of both quarks and adjoint scalars. We also propose
a non-perturbative expression for the dynamical DeTar correlators at small
spatial momenta.Comment: 21 pages, Latex, uses axodra
Composite fermion wave functions as conformal field theory correlators
It is known that a subset of fractional quantum Hall wave functions has been
expressed as conformal field theory (CFT) correlators, notably the Laughlin
wave function at filling factor ( odd) and its quasiholes, and the
Pfaffian wave function at and its quasiholes. We develop a general
scheme for constructing composite-fermion (CF) wave functions from conformal
field theory. Quasiparticles at are created by inserting anyonic
vertex operators, , that replace a subset of the electron
operators in the correlator. The one-quasiparticle wave function is identical
to the corresponding CF wave function, and the two-quasiparticle wave function
has correct fractional charge and statistics and is numerically almost
identical to the corresponding CF wave function. We further show how to exactly
represent the CF wavefunctions in the Jain series as the CFT
correlators of a new type of fermionic vertex operators, ,
constructed from free compactified bosons; these operators provide the CFT
representation of composite fermions carrying flux quanta in the CF Landau level. We also construct the corresponding quasiparticle- and
quasihole operators and argue that they have the expected fractional charge and
statistics. For filling fractions 2/5 and 3/7 we show that the chiral CFTs that
describe the bulk wave functions are identical to those given by Wen's general
classification of quantum Hall states in terms of -matrices and - and
-vectors, and we propose that to be generally true. Our results suggest a
general procedure for constructing quasiparticle wave functions for other
fractional Hall states, as well as for constructing ground states at filling
fractions not contained in the principal Jain series.Comment: 26 pages, 3 figure
Bosonic and fermionic single-particle states in the Haldane approach to statistics for identical particles
We give two formulations of exclusion statistics (ES) using a variable number
of bosonic or fermionic single-particle states which depend on the number of
particles in the system. Associated bosonic and fermionic ES parameters are
introduced and are discussed for FQHE quasiparticles, anyons in the lowest
Landau level and for the Calogero-Sutherland model. In the latter case, only
one family of solutions is emphasized to be sufficient to recover ES;
appropriate families are specified for a number of formulations of the
Calogero-Sutherland model. We extend the picture of variable number of
single-particle states to generalized ideal gases with statistical interaction
between particles of different momenta. Integral equations are derived which
determine the momentum distribution for single-particle states and distribution
of particles over the single-particle states in the thermal equilibrium.Comment: 6 pages, REVTE
Laughlin Wave Function and One-Dimensional Free Fermions
Making use of the well-known phase space reduction in the lowest Landau
level(LLL), we show that the Laughlin wave function for the
case can be obtained exactly as a coherent state representation of an one
dimensional wave function. The system consists of copies of
free fermions associated with each of the electrons, confined in a common
harmonic well potential. Interestingly, the condition for this exact
correspondence is found to incorporate Jain's parton picture. We argue that,
this correspondence between the free fermions and quantum Hall effect is due to
the mapping of the system under consideration, to the Gaussian unitary
ensemble in the random matrix theory.Comment: 7 pages, Latex , no figure
Matrix Model Description of Laughlin Hall States
We analyze Susskind's proposal of applying the non-commutative Chern-Simons
theory to the quantum Hall effect. We study the corresponding regularized
matrix Chern-Simons theory introduced by Polychronakos. We use holomorphic
quantization and perform a change of matrix variables that solves the Gauss law
constraint. The remaining physical degrees of freedom are the complex
eigenvalues that can be interpreted as the coordinates of electrons in the
lowest Landau level with Laughlin's wave function. At the same time, a
statistical interaction is generated among the electrons that is necessary to
stabilize the ground state. The stability conditions can be expressed as the
highest-weight conditions for the representations of the W-infinity algebra in
the matrix theory. This symmetry provides a coordinate-independent
characterization of the incompressible quantum Hall states.Comment: 31 pages, large additions on the path integral and overlaps, and on
the W-infinity symmetr
Classical phase space and statistical mechanics of identical particles
Starting from the quantum theory of identical particles, we show how to
define a classical mechanics that retains information about the quantum
statistics. We consider two examples of relevance for the quantum Hall effect:
identical particles in the lowest Landau level, and vortices in the
Chern-Simons Ginzburg-Landau model. In both cases the resulting {\em classical}
statistical mechanics is shown to be a nontrivial classical limit of Haldane's
exclusion statistics.Comment: 40 pages, Late
Characterising Probabilistic Processes Logically
In this paper we work on (bi)simulation semantics of processes that exhibit
both nondeterministic and probabilistic behaviour. We propose a probabilistic
extension of the modal mu-calculus and show how to derive characteristic
formulae for various simulation-like preorders over finite-state processes
without divergence. In addition, we show that even without the fixpoint
operators this probabilistic mu-calculus can be used to characterise these
behavioural relations in the sense that two states are equivalent if and only
if they satisfy the same set of formulae.Comment: 18 page
- …
