898 research outputs found
Stability and Dynamics of Cross Solitons in Harmonically Confined Bose-Einstein Condensates
We examine the stability and dynamics of a family of crossed dark solitons in
a harmonically confined Bose-Einstein condensate in two dimensions. Working in
a regime where the fundamental snake instability is suppressed, we show the
existence of an instability which leads to an interesting collapse and revival
of the initial state for the fundamental case of two crossed solitons. The
instability originates from the singular point where the solitons cross, and we
characterise it by examining the Bogoliubov spectrum. Finally, we extend the
treatment to systems of higher symmetry.Comment: 7 pages, 7 figure
Localized quantum walks as secured quantum memory
We show that a quantum walk process can be used to construct and secure
quantum memory. More precisely, we show that a localized quantum walk with
temporal disorder can be engineered to store the information of a single,
unknown qubit on a compact position space and faithfully recover it on demand.
Since the localization occurss with a finite spread in position space, the
stored information of the qubit will be naturally secured from the simple
eavesdropper. Our protocol can be adopted to any quantum system for which
experimental control over quantum walk dynamics can be achieved.Comment: 7 pages, 4 figure
Pairing of a harmonically trapped fermionic Tonks-Girardeau gas
The fermionic Tonks-Girardeau (FTG) gas is a one-dimensional spin-polarized
Fermi gas with infinitely strong attractive zero-range odd-wave interactions,
arising from a confinement-induced resonance reachable via a three-dimensional
p-wave Feshbach resonance. We investigate the off-diagonal long-range order
(ODLRO) of the FTG gas subjected to a longitudinal harmonic confinement by
analyzing the two-particle reduced density matrix for which we derive a
closed-form expression. Using a variational approach and numerical
diagonalization we find that the largest eigenvalue of the two-body density
matrix is of order N/2, where N is the total particle number, and hence a
partial ODLRO is present for a FTG gas in the trap.Comment: 4 pages, 3 figures, revtex
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