Observation of the Berezinskii-Kosterlitz-Thouless transition in a two-dimensional Bose gas via matter-wave interferometry

Physical Review Letters American Physical Society 128:25 (2022) 250402

Authors:

S Sunami, Vp Singh, D Garrick, A Beregi, Aj Barker, K Luksch, E Bentine, L Mathey, Cj Foot

Abstract:

We probe local phase fluctuations of trapped two-dimensional (2D) Bose gases using matter-wave interferometry. This enables us to measure the phase correlation function, which changes from an algebraic to an exponential decay when the system crosses the Berezinskii-Kosterlitz-Thouless (BKT) transition. We determine the temperature dependence of the BKT exponent η and find the critical value ηc = 0.17(3) for our trapped system. Furthermore, we measure the local vortex density as a function of the local phase-space density, which shows a scale-invariant behaviour across the transition. Our experimental investigation is supported by Monte Carlo simulations and provides a comprehensive understanding of the BKT transition in a trapped system.

Quench dynamics of 2D Bose gases across the BKT critical point

(2022)

Authors:

SHINICHI SUNAMI, David Garrick, ABEL BEREGI, ELLIOT BENTINE, CHRISTOPHER FOOT

Abstract:

APS March Meeting 2022 focus session talk

Faraday-imaging-induced squeezing of a double-well Bose-Einstein condensate

PHYSICAL REVIEW A 104:5 (2021) ARTN 053324

Authors:

Ebubechukwu O Ilo-Okeke, Shinichi Sunami, Christopher J Foot, Tim Byrnes

Demonstration of an atomic frequency comb quantum memory using velocity-selective pumping in warm alkali vapour

Conference on Lasers and Electro-Optics, OSA Technical Digest (Optical Society of America, 2020) OSA Publishing (2021)

Authors:

Thomas Hird, Dougal Main, S Gao, E Oguz, Dylan Saunders, Ian Walmsley, Patrick Ledingham

Abstract:

We present the first demonstration of velocity-selective pumping in an atomic vapour to preserve light-matter coherence. Control is illustrated by a subsequent demonstration of an atomic frequency comb quantum memory realised in the vapour.

Observation of the BKT Transition in a 2D Bose Gas via Matter-Wave Interferometry

(2021)

Authors:

Shinichi SUNAMI, Vijay Singh, David Garrick, Abel BEREGI, Adam BARKER, Kathrin Luksch, Elliot BENTINE, Ludwig Mathey, CHRISTOPHER FOOT