63 research outputs found
Atomic Scattering in Presence of an External Confinement and a Gas of Impenetrable Bosons
We calculate, within the pseudopotential approximation, a one-dimensional
scattering amplitude and effective one-dimensional interaction potential for
atoms confined transversally by an atom waveguide or highly elongated
``cigar''-shaped atomic trap. We show that in the low-energy scattering regime,
the scattering process degenerates to a total reflection suggesting an
experimental realization of a famous model in theoretical physics - a
one-dimensional gas of impenetrable bosons (``Tonks'' gas). We give an estimate
for suitable experimental parameters for alkali atoms confined in waveguides.Comment: 5 pages, 2 figures; list of atoms - candidates for the Tonks gas
realisation is restricted to the positive scatt. length; Cs is excluded from
the list; some new references added; minor changes in the text; accepted in
PRL June 22, 199
Relaxation in a Completely Integrable Many-Body Quantum System: An Ab Initio Study of the Dynamics of the Highly Excited States of Lattice Hard-Core Bosons
In this Letter we pose the question of whether a many-body quantum system
with a full set of conserved quantities can relax to an equilibrium state, and,
if it can, what the properties of such state are. We confirm the relaxation
hypothesis through a thorough ab initio numerical investigation of the dynamics
of hard-core bosons on a one-dimensional lattice. Further, a natural extension
of the Gibbs ensemble to integrable systems results in a theory that is able to
predict the mean values of physical observables after relaxation. Finally, we
show that our generalized equilibrium carries more memory of the initial
conditions than the usual thermodynamic one. This effect may have many
experimental consequences, some of which having already been observed in the
recent experiment on the non-equilibrium dynamics of one-dimensional hard-core
bosons in a harmonic potential [T. Kinoshita, T. Wenger, D. S. Weiss, Nature
(London) 440, 900 (2006)].Comment: 4 pages, 2 figures, published versio
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