Quantum state of two trapped Bose-Einstein condensates with a Josephson

We consider the precise quantum state of two trapped, coupled Bose Einstein condensates in the two-mode approximation. We seek a representation of the state in terms of a Wigner-like distribution on the two-mode Bloch sphere. The problem is solved using a self-consistent rotation of the unknown stat...

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Bibliographic Details
Main Authors: M. J. Steel, M. J. Collett
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 1997
Subjects:
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.306.2094
http://arxiv.org/pdf/cond-mat/9710124v1.pdf
Description
Summary:We consider the precise quantum state of two trapped, coupled Bose Einstein condensates in the two-mode approximation. We seek a representation of the state in terms of a Wigner-like distribution on the two-mode Bloch sphere. The problem is solved using a self-consistent rotation of the unknown state to the south pole of the sphere. The two-mode Hamiltonian is projected onto the harmonic oscillator phase plane, where it can be solved by standard techniques. Our results show how the number of atoms in each trap and the squeezing in the number difference depend on the physical parameters. Considering negative scattering lengths, we show that there is a regime of squeezing in the relative phase of the condensates which occurs for weaker interactions than the superposition states found by Cirac et al (quantph/9706034, 13 June 1997). The phase squeezing is also apparent in mildly asymmetric trap configurations. 1 I.