287 research outputs found
Nilpotent Gauging of SL(2,R) models, and Liouville Field
We consider the gauging of WZNW model by its nilpotent subgroup
E(1). The resulting space-time of the corresponding sigma model is seen to
collapse to a one dimensional field theory of Liouville. Gauging the diagonal
subgroup of theory yields an
extremal three dimensional black string. We show that these solutions are
obtained from the two dimensional black hole of Witten and the three
dimensional black string of Horne and Horowitz by boosting the gauge group.Comment: 17 pages, late
Attractor solutions for general hessence dark energy
As a candidate for the dark energy, the hessence model has been recently
introduced. We discuss the critical points of this model in almost general
case, that is for arbitrary hessence potential and almost arbitrary
hessence-background matter interaction. It is shown that in all models, there
always exist some stable late-time attractors. It is shown that our general
results coincide with those solutions obtained earlier for special cases, but
some of them are new. These new solutions have two unique characteristics.
First the hessence field has finite value in these solutions and second, their
stabilities depend on the second derivative of the hessence potential.Comment: 11 pages. Add some explanations about the autonomousity of the
equations, and also a conclusion section was added. To appear in Phys. Rev. D
(2006
Coulomb gas representation of quantum Hall effect on Riemann surfaces
Using the correlation function of chiral vertex operators of the Coulomb gas
model, we find the Laughlin wavefunctions of quantum Hall effect, with filling
factor , on Riemann sufaces with Poincare metric. The same is done
for quasihole wavefunctions. We also discuss their plasma analogy.Comment: 10 pages, LaTex, the paper is completely rewritten, It will be
appeared in : Jour. Phys. A 32 (1999
Cosmological coincidence problem in interacting dark energy models
An interacting dark energy model with interaction term is considered. By studying the model near the
transition time, in which the system crosses the w=-1 phantom-divide-line, the
conditions needed to overcome the coincidence problem is investigated. The
phantom model, as a candidate for dark energy, is considered and for two
specific examples, the quadratic and exponential phantom potentials, it is
shown that it is possible the system crosses the w=-1 line, meanwhile the
coincidence problem is alleviated, the two facts that have root in
observations.Comment: 15 pages, LaTeX. Some minor explanations are added. To be published
in Phys. Rev.
Laughlin states on the Poincare half-plane and its quantum group symmetry
We find the Laughlin states of the electrons on the Poincare half-plane in
different representations. In each case we show that there exist a quantum
group symmetry such that the Laughlin states are a representation of
it. We calculate the corresponding filling factor by using the plasma analogy
of the FQHE.Comment: 9 pages,Late
A new class of integrable diffusion-reaction processes
We consider a process in which there are two types of particles, A and B, on
an infinite one-dimensional lattice. The particles hop to their adjacent sites,
like the totally asymmetric exclusion process (ASEP), and have also the
following interactions: A+B -> B+B and B+A -> B+B, all occur with equal rate.
We study this process by imposing four boundary conditions on ASEP master
equation. It is shown that this model is integrable, in the sense that its
N-particle S-matrix is factorized into a product of two-particle S-matrices
and, more importantly, the two-particle S-matrix satisfy quantum Yang-Baxter
equation. Using coordinate Bethe-ansatz, the N-particle wavefunctions and the
two-particle conditional probabilities are found exactly.
Further, by imposing four reasonable physical conditions on two-species
diffusion-reaction processes (where the most important ones are the equality of
the reaction rates and the conservation of the number of particles in each
reaction), we show that among the 4096 types of the interactions which have
these properties and can be modeled by a master equation and an appropriate set
of boundary conditions, there are only 28 independent interactions which are
integrable. We find all these interactions and also their corresponding wave
functions. Some of these may be new solutions of quantum Yang-Baxter equation.Comment: LaTex,16 pages, some typos are corrected, will be appeared in Phys.
Rev. E (2000
Transition from quintessence to phantom phase in quintom model
Assuming the Hubble parameter is a continuous and differentiable function of
comoving time, we investigate necessary conditions for quintessence to phantom
phase transition in quintom model. For power-law and exponential potential
examples, we study the behavior of dynamical dark energy fields and Hubble
parameter near the transition time, and show that the phantom-divide-line w=-1
is crossed in these models.Comment: LaTeX, 19 pages, four figures, some minor changes in Introduction,
two figures added and the references updated, accepted for publication in
Phys. Rev.
Exactly solvable models through the generalized empty interval method: multi-species and more-than-two-site interactions
Multi-species reaction-diffusion systems, with more-than-two-site interaction
on a one-dimensional lattice are considered. Necessary and sufficient
constraints on the interaction rates are obtained, that guarantee the
closedness of the time evolution equation for 's, the
expectation value of the product of certain linear combination of the number
operators on consecutive sites at time .Comment: 10 pages, LaTe
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