2003/12/31 by Khan W. Mahmud, Heidi Perry, William P. Reinhardt · 7 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum Mechanics and Applications #Quantum, superfluid, helium dynamics #cond-mat.soft #quant-ph
paper · pdf · doi:10.1103/physreva.71.023615
published as Phys. Rev. A 71, 023615 (2005) · revised version, 13 pages, 13 figures
arxiv created 2004/03/19 · openalex publication_date 2005/02/28 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We present a quantum phase-space model of the Bose-Einstein condensate (BEC) in a double-well potential. In a quantum two-mode approximation we examine the eigenvectors and eigenvalues and find that the energy correlation diagram indicates a transition from a delocalized to a fragmented regime. Phase-space information is extracted from the stationary quantum states using the Husimi distribution function. We show that the mean-field phase-space characteristics of a nonrigid physical pendulum arises from the exact quantum states, and that only 4--8 particles per well are needed to reach the semiclassical limit. For a driven double-well BEC, we show that the classical chaotic dynamics is manifest in the dynamics of the quantum states. Phase-space analogy also suggests that a \ensuremathπ phase-displaced wave packet put on the unstable fixed point on a separatrix bifurcates to create a superposition of two pendulum rotor states---a macroscopic superposition state of BEC. We show that the choice of initial barrier height and ramping, following a \ensuremathπ phase imprinting on the condensate, can be used to generate controlled entangled number states with tunable extremity and sharpness.