Fidelity decay in trapped Bose-Einstein condensates

Abstract

The quantum coherence of a Bose-Einstein condensate is studied using the concept of quantum fidelity (Loschmidt echo). The condensate is confined in an elongated anharmonic trap and subjected to a small random potential such as that created by a laser speckle. Numerical experiments show that the quantum fidelity stays constant until a critical time, after which it drops abruptly over a single trap oscillation period. The critical time depends logarithmically on the number of condensed atoms and on the perturbation amplitude. This behavior may be observable by measuring the interference fringes of two condensates evolving in slightly different potentials.

4 pages, to appear in Physical Review Letters, February 2008

References in corpus (4)

• Interference of an array of independent Bose-Einstein condensates
• Superfluidity versus Anderson localization in a dilute Bose gas
• Decay of the classical Loschmidt echo in integrable systems
• Loschmidt echo in a system of interacting electrons

Cited by in corpus (4)

• Decoherence, Entanglement and Irreversibility in Quantum Dynamical Systems with Few Degrees of Freedom
• Delocalization induced by nonlinearity in systems with disorder
• Effective one-body dynamics in multiple-quantum NMR experiments
• Stability of Fock states in a two-component Bose-Einstein condensate with a regular classical counterpart