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| Phase-space methods for quantum gases and quantum Brownian motion |
| 2008-06-19
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Speaker : Professor Peter D. Drummond Australian Centre for Quantum-Atom Optics, University of Queensland, Brisbane, Australia
Date : 2008-06-19 10:00
Venue :
ITP New Building 6620, 理论物理研究所新楼六层报告厅
Abstract : In this talk, recent developments of phase-space techniques useful for quantum gases will be analyzed, including large-scale first-principles simulations of quantum many-body dynamics with over 10 to 5 atoms, and over 10 to 7 polaritons. The talk will explain techniques suitable for the treatment of quantum dynamics in Brownian motion, where one quantum particle is immersed in a sea of particles of a different species, but without making a Markov or similar reservoir approximations.
We focus particularly on the use of positive-P techniques, where non-classical phase-space methods are used both for the quantum particle in Brownian motion, and the quantum gas which acts as the host.
Historically, phase-space methods originated with Wigner and Moyal's ideas of obtaining classical-like equations for quantum mechanics. However, there is no generally equivalent stochastic process in a purely classical phase-space, except for systems with a quadratic Hamiltonian and linear equations of motion. Instead of these methods, we will examine the use of non-classical phase-space, in which a phase-space of higher dimension than the classical one is utilized.
In particular, we consider the application of phase-space techniques, which are useful when a highly degenerate quantum gas interacts dynamically with another quantum particle of much lower density. We show that this technique is capable of solving quantum Brownian motion dynamics in a non-perturbative way, even with interacting host particles and very low temperatures
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