13,224 research outputs found
Drifting diffusion on a circle as continuous limit of a multiurn Ehrenfest model
We study the continuous limit of a multibox Erhenfest urn model proposed
before by the authors. The evolution of the resulting continuous system is
governed by a differential equation, which describes a diffusion process on a
circle with a nonzero drifting velocity. The short time behavior of this
diffusion process is obtained directly by solving the equation, while the long
time behavior is derived using the Poisson summation formula. They reproduce
the previous results in the large (number of boxes) limit. We also discuss
the connection between this diffusion equation and the Schrdinger
equation of some quantum mechanical problems.Comment: 4 pages prevtex4 file, 1 eps figur
Symmetry between repulsive and attractive interactions in driven-dissipative Bose-Hubbard systems
The driven-dissipative Bose-Hubbard model can be experimentally realized with
either negative or positive onsite detunings, inter-site hopping energies, and
onsite interaction energies. Here we use one-dimensional matrix product density
operators to perform a fully quantum investigation of the dependence of the
non-equilibrium steady states of this model on the signs of these parameters.
Due to a symmetry in the Lindblad master equation, we find that simultaneously
changing the sign of the interaction energies, hopping energies, and chemical
potentials leaves the local boson number distribution and inter-site number
correlations invariant, and the steady-state complex conjugated. This shows
that all driven-dissipative phenomena of interacting bosons described by the
Lindblad master equation, such as "fermionization" and "superbunching", can
equivalently occur with attractive or repulsive interactions.Comment: single column 12 pages, 4 figures, 1 tabl
Magnetic Field Effects in the Pseudogap Phase: A Precursor Superconductivity Scenario
We demonstrate that the observed dependences of and on small
magnetic fields can be readily understood in a precursor superconductivity
approach to the pseudogap phase. In this approach, the presence of a pseudogap
at (but not at ) and the associated suppression of the density of
states lead to very different sensitivities to pair-breaking perturbations for
the two temperatures. Our semi-quantitative results address the puzzling
experimental observation that the coherence length is weakly dependent on
hole concentration throughout most of the phase diagram. We present our
results in a form which can be compared with the recent experiments of
Shibauchi et al, and argue that orbital effects contribute in an important way
to the dependence of .Comment: 6 pages, 1 figure, elsart.cls included. Submitted to the proceeding
of SNS 2001, Chicag
Mass Spectra of N=2 Supersymmetric SU(n) Chern-Simons-Higgs Theories
An algebraic method is used to work out the mass spectra and symmetry
breaking patterns of general vacuum states in N=2 supersymmetric SU(n)
Chern-Simons-Higgs systems with the matter fields being in the adjoint
representation. The approach provides with us a natural basis for fields, which
will be useful for further studies in the self-dual solutions and quantum
corrections. As the vacuum states satisfy the SU(2) algebra, it is not
surprising to find that their spectra are closely related to that of angular
momentum addition in quantum mechanics. The analysis can be easily generalized
to other classical Lie groups.Comment: 17 pages, use revte
New Predictions for generalized spin polarizabilities from heavy baryon chiral perturbation theory
We extract the next-to-next-to-leading order results for spin-flip
generalized polarizabilities (GPs) of the nucleon from the spin-dependent
amplitudes for virtual Compton scattering (VCS) at in heavy
baryon chiral perturbation theory. At this order, no unknown low energy
constants enter the theory, allowing us to make absolute predictions for all
spin-flip GPs. Furthermore, by using constraint equations between the GPs due
to nucleon crossing combined with charge conjugation symmetry of the VCS
amplitudes, we get a next-to-next-to-next-to-leading order prediction for one
of the GPs. We provide estimates for forthcoming double polarization
experiments which allow to access these spin-flip GPs of the nucleon.Comment: 15 pages, 3 figure
Magnetic field effects on and the pseudogap onset temperature in cuprate superconductors
We study the sensitivity of and the pseudogap onset temperature,
, to low fields, , for cuprate superconductors, using a BCS-based
approach extended to arbitrary coupling. We find that and , which
are of the same superconducting origin, have very different dependences.
The small coherence length makes rather insensitive to the field.
However, the presence of the pseudogap at makes more sensitive to
. Our results for the coherence length fit well with existing
experiments. We predict that very near the insulator will rapidly
increase.Comment: 4 pages, 1 figure, contribution to the PPHMF-IV conference, Oct. 200
Supersymmetric Electroweak Parity Nonconservation in Top Quark Pair Production at the Fermilab Tevatron
We evaluate the supersymmetric (SUSY) electroweak corrections to the effect
of parity nonconservation in production at the
Fermilab Tevatron predicted by the Minimal Supersymmetric Model (MSSM). We find
that the parity nonconserving asymmetry from the SUSY electroweak and SUSY
Yukawa loop corrections predicted by the minimal supergravity (mSUGRA) model
and the MSSM models with scenarios motivated by current data is about one
percent. It will be challenging to observe such a small asymmetry at the
Tevatron with 10 fb^{-1} of luminosity. It could however be observable if both
the top- and bottom-squarks are light and is smaller than 1,
though theses parameters are not favored by mSUGRA.Comment: revised version, some new numerical results adde
The Chern-Simons Coefficient in Supersymmetric Non-abelian Chern-Simons Higgs Theories
By taking into account the effect of the would be Chern-Simons term, we
calculate the quantum correction to the Chern-Simons coefficient in
supersymmetric Chern-Simons Higgs theories with matter fields in the
fundamental representation of SU(n). Because of supersymmetry, the corrections
in the symmetric and Higgs phases are identical. In particular, the correction
is vanishing for N=3 supersymmetric Chern-Simons Higgs theories. The result
should be quite general, and have important implication for the more
interesting case when the Higgs is in the adjoint representation.Comment: more references and explanation about rgularization dpendence are
included, 13 pages, 1 figure, latex with revte
- âŠ