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Quantum phase transition in one-dimensional Bose-Einstein condensates with attractive interactions

2003; American Physical Society; Volume: 67; Issue: 1 Linguagem: Inglês

10.1103/physreva.67.013608

1538-4446

Rina Kanamoto, Hiroki Saito, Masahito Ueda,

Quantum, superfluid, helium dynamics

Motivated by the recent development of the Feshbach technique, we studied the ground and low-lying excited states of attractive Bose-Einstein condensates on a one-dimensional ring as a function of the strength of interactions. The Gross-Pitaevskii mean-field theory predicts a quantum phase transition between a uniform condensate and a bright soliton, and a gapless singular cusp in the Bogoliubov excitation spectrum at the critical point. However, the exact diagonalization reveals the presence of an energy gap at the critical point, where the singularity is smeared by quantum fluctuations.