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Physics Seminar - Rob McDonald

Thursday, 29 August 2019

Physics Department

Rob McDonald

Department of Physics

University of Otago

"Anomalous Dissipation in Bose Gases: Analytic Theory of Energy Damping"

The stochastic projected Gross-Pitaevskii equation (SPGPE) provides a first-principles description of a Bose-Einstein condensate in the presence of a thermal cloud. Interactions between the condensate and thermal cloud are permitted through two distinct processes; number damping and energy damping. Number damping, involving particle transfer between the condensate and thermal cloud, has historically received much attention, while energy damping, a strictly number-conserving process, has been largely ignored. Here we provide an analytic investigation into the role of energy damping in several systems. First we perform linear fluctuation analysis of a homogeneous system including drift and diffusion from both damping processes. Then, using newly developed techniques, we analyse the finite-temperature steady-state properties of a harmonically trapped degenerate Bose gas in the Thomas-Fermi regime. This reveals that each of the two damping processes is significant for different aspects of the system. We finish by briefly considering the stochastic energy-damped motion of a quantum vortex in a disc-like system.

WHEN: Thursday 29 August 2019
WHERE: Room 314, Science 3 Building
TIME: 3.00 pm–4.00 pm

All interested are welcome to attend

Light refreshments to follow in Common Room