Cold atoms seminar: Quantum behaviour of a heavy impurity in a Bose gas

Dr Jesper Levinsen, FLEET, Monash University

Zoom meeting

The scenario of an infinitely heavy impurity in a quantum medium is a fundamental problem in physics, with relevance ranging from electron gases to open quantum systems. Here I will consider the case of a heavy impurity interacting with a dilute Bose gas at zero temperature – the so-called Bose polaron. When the impurity-boson interactions are short ranged, I will show that boson-boson interactions induce a quantum blockade effect, where a single boson can effectively block or screen the impurity potential. This behaviour depends on the quantum granular nature of the Bose gas and thus cannot be captured within a standard classical-field description. Using a combination of exact quantum Monte Carlo methods and a truncated basis approach, I will expose how the polaron ground-state energy is linked to the spatial structure of the quantum correlations, spanning the infrared to ultraviolet physics.

Dr Jesper Levinsen is an ARC Future Fellow at Monash University. As a theoretical physicist, within FLEET he works on topological Floquet superfluids and on the dynamical manipulation of superfluids with impurities.

Australia-New Zealand cold-atom seminars hosts a seminar once a month for the Australia–New Zealand cold atom research community.  The purpose is to encourage and facilitate ongoing discussions and collaboration in the local community.  Seminars are held on the last Friday of the month (except for December) at 1pm Melbourne time (which is normally 3pm New Zealand time).  Brought to you by EQUS, FLEET and the University of Queensland School of Mathematics and Physics.