3/2-Body Correlations and Coherence in Bose-Einstein Condensates

Abstract

We construct a variational wave function for the ground state of weakly interacting bosons that gives a lower energy than the mean-field Girardeau-Arnowitt (or Hartree-Fock-Bogoliubov) theory. This improvement is brought about by incorporating the dynamical 3/2-body processes where one of two colliding non-condensed particles drops into the condensate and vice versa. The processes are also shown to transform the one-particle excitation spectrum into a bubbling mode with a finite lifetime even in the long-wavelength limit. These 3/2-body processes, which give rise to dynamical exchange of particles between the non-condensate reservoir and condensate absent in ideal gases, are identified as a key mechanism for realizing and sustaining macroscopic coherence in Bose-Einstein condensates.

arXiv comment12 pages, 7 figures

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Cited by in corpus (6)

• A Renormalization-Group Study of Interacting Bose-Einstein condensates: Absence of the Bogoliubov Mode below Four ($T>0$) and Three ($T=0$) Dimensions
• A Renormalization-Group Study of Interacting Bose-Einstein Condensates: II. Anomalous Dimension $\eta$ for $d\lesssim 4$ at Finite Temperatures
• Ground-State Wave Function with Interactions between Different Species in $M$-Component Miscible Bose-Einstein Condensates
• Number-Phase Fluctuations in Isolated Superconductors
• Variational Wave Function for Inhomogeneous Bose--Einstein Condensate with 3/2-Body Correlations
• Variational Approach to Many-Body Problems Incorporating Many-Body Effects at Finite Temperature