770 research outputs found
Coherence Properties of a Bose-Einstein Condensate in an Optical Superlattice
We study the effect of a one dimensional optical superlattice on the
superfluid fraction, number squeezing, dynamic structure factor and the
quasi-momentum distribution of the Mott-insulator. We show that due to the
secondary lattice,there is a decrease in the superfluid fraction and the number
fluctuation. The dynamic structure factor which can be measured by Bragg
spectroscopy is also suppressed due to the addition of the secondary lattice.
The visibility of the interference pattern (the quasi-momentum distribution)of
the Mott-insulator is found to decrease due to the presence of the secondary
lattice. Our results have important implications in atom interferometry and
quantum computation in optical lattices.Comment: 12 pages, 5 figure
Influence of Virtual Photon Process on the Generation of Squeezed Light from Atoms in an Optical Cavity
We show that a collection of two-level atoms in an optical cavity beyond the
rotating wave approximation and in the dispersive and strong-coupling regime
constitutes a nonlinear medium and is capable of generating squeezed state of
light. It is found that squeezing produced in the strong-coupling regime is
significantly higher compared to that produced in the dispersive limit. On the
other hand, we also show that it could be possible to observe the Dicke
superradiant quantum phase transition in the dispersive regime where the vector
potential term is negligible. Such a system can be an essential component of a
larger quantum-communication system.Comment: 6 pages, 3 figures, Comments Welcom
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