Description:

Abstract:

This seminar will describe two topics in atom interferometry. Firstly, experiments using a quenched two-dimensional Bose gas to investigate the nonequilibrium dynamics of a many-body quantum system, which is a fundamental issue in statistical physics. We probe universal properties of these systems by measuring the dynamics triggered by a quench from the superfluid to normal phase across the Berezinskii-Kosterlitz-Thouless transition. By splitting the two-dimensional gas into two clouds, with a separation of a few microns, we suddenly reduce the density thus quenching the system across the critical point. The subsequent relaxation dynamics were probed with matter-wave interferometry to measure the local phase fluctuations. We show that both the phase correlation function and vortex density follow time evolutions that obey universal scaling laws. This conclusion is interpreted by means of real-time renormalization group theory. In addition to the results reported in [1], directions for future investigation using Bose gases of rubidium atoms will be discussed. 

Secondly, a brief overview will be given of a proposed scheme for measuring the fine-structure constant (alpha) more precisely, adapted from the methods being developed for large-scale atom interferometry in the MAGIS-100 collaboration (in the US: Kovachy, Hogan et al.), and associated work by AION (based in the UK).  

[1] Universal scaling of the dynamic BKT transition in quenched 2D Bose gases. Science, 382, 443 (2023). 

Shinichi Sunami, Vijay Singh, David Garrick, Abel Beregi, Adam Barker, Kathrin Luksch, Elliot Bentine, Ludwig Mathey, Christopher Foot

Speaker: Christopher Foot, Oxford University

Keywords: Physics, CFP