2005/11/30 by Rina Kanamoto, Hiroki Saito, Masahito Ueda · 3 citations
Physics and Astronomy · #Bose gas #Bose–Einstein condensate #Classical mechanics #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Explicit symmetry breaking #Ground state #Hamiltonian (control theory) #Mean field theory #Nonlinear system #Physics #Quantum electrodynamics #Quantum mechanics #Quantum, superfluid, helium dynamics #Soliton #Spontaneous symmetry breaking #Strong Light-Matter Interactions #Superposition principle #Symmetry (geometry) #Symmetry breaking #Translational symmetry #cond-mat.other
paper · pdf · doi:10.1103/physreva.73.033611
published as Phys. Rev. A 73, 033611 (2006) · 14 pages, 13 figures
openalex publication_date 2006/03/15 · arxiv created 2006/03/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We employ mean-field, Bogoliubov and many-body theories to study critical fluctuations in the position and momentum of a Bose-Einstein condensate whose translation symmetry is spontaneously broken due to attractive interactions. In a homogeneous system, the many-body ground state of the symmetry-preserving Hamiltonian is very fragile against superposition of low-lying states, while the mean-field theory predicts a stable bright soliton which spontaneously breaks translation symmetry. We show that weak symmetry-breaking perturbations cause the translation-symmetric many-body ground state to cross over to a many-body bright soliton. We argue that the center-of-mass fluctuations in the soliton state arise primarily from the depletion of the condensate to translation modes. We develop an extended mean-field theory to analytically reproduce these results obtained by the exact diagonalization method.