报告题目: |
Fragmented Many-Body Ground States for Scalar Bosons in a Single Trap |
报告人: |
Uwe Fischer |
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Seoul National University
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报告时间: |
2010-10-20 15:00 |
报告地点: |
清华大学高等研究院 科学馆322报告厅 |
主办单位: |
清华大学高等研究院 |
简介: |
We investigate whether the many-body states of bosons in a generalized
two-mode model with arbitrary long-range interactions and single-
particle orbitals are coherent or fragmented. It is demonstrated that
fragmentation can take place in a single trap for positive values of
the interaction couplings, implying that the system is potentially
stable. Fragmentation in terms of the single-particle density matrix
is owed to a positive coupling constant in front of the boson pair
exchange term in the Hamiltonian. As an application, we have derived
fragmentation of the condensate in the weakly confining directions of
quasi-1D respectively quasi-2D gases into mutually incoherent
macroscopic pieces, upon increasing a dimensionless interaction
measure beyond a critical value. Fragmented condensate many-body
states in low-dimensional systems therefore occur well before the
thermodynamic limit of infinite extension is reached, in which phase
fluctuations of the matter wave field create an infinite number of non-
macroscopic fragments. |
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