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arXiv · 1810.12984

Phase-space representations of thermal Bose-Einstein condensates

King Ng·Rodney Polkinghorne·Bogdan Opanchuk·Peter D. Drummond
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Abstract

Phase-space methods allow one to go beyond the mean-field approximation to simulate the quantum dynamics of interacting fields. Here, we obtain a technique for initializing either Wigner or positive-P phase-space simulations of Bose-Einstein condensates with quantum states at a finite temperature. As a means to calculate the initial states, we introduce the idea of a nonlinear chemical potential, which removes the zero-momentum phase-noise divergences of Bogoliubov theory to give a diagonal Hamiltonian. The resulting steady-state quantum theory is then directly applicable to the calculations of initial conditions for quantum simulations of BEC dynamics using phase-space techniques. These methods allow efficient and scalable simulation of large Bose-Einstein condensates. We suggest that nonlinear chemical potentials may have a general applicability to cases of broken symmetry.

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King Ng, Rodney Polkinghorne, Bogdan Opanchuk, Peter D. Drummond. 2018-10-30. Phase-space representations of thermal Bose-Einstein condensates. https://doi.org/10.1088/1751-8121%2Faaeeb1

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