17-22 July 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

Tunneling Times and Interaction-Driven Spin Rotations in a Two-component BEC

19 Jul 2022, 17:00
1h 30m
Hart House (Hart House)

Hart House

Hart House

7 Hart House Cir, Toronto, ON M5S 3H3
Poster presentation Degenerate gases, many-body physics, and quantum simulation Poster session


How much time does a tunneling particle spend in a barrier? A Larmor clock, one proposal to answer this question, measures the interaction between the particle and the barrier region using the spin degree of freedom of the particle to clock the dwell time inside the barrier. We report on precise Larmor time measurements of a Bose-Einstein condensate of 87Rb atoms tunneling through an optical barrier. We observe that atoms generally spend less time tunneling through higher barriers and that this time decreases for lower energy particles, confirming longstanding predictions of tunneling times. In addition, we present evidence of spin waves generated in the reflected portion of the condensate. Due to the coincidence of scattering lengths in 87Rb, a BEC in a mixture of two hyperfine states behaves as a phase-coherent yet distinguishable two-component fluid. Reflection from the barrier creates a counter-propagating matter wave with spin partly transverse to the spin of the forward-going wave, initiating interaction-driven rotations due to the different interaction energies experienced by parallel versus anti-parallel spins. We observe one oscillation of a spin wave for low Rabi frequencies and study the transition where spin rotations become independent of the external coupling and instead are dominated by the interaction-driven effects.

Presenter name David Spierings
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Primary authors

Dr David Spierings (University of Toronto) Joseph McGowan (University of Toronto) Nick Mantella (University of Toronto) Harshil Neeraj (University of Toronto) Prof. Joseph Thywissen (University of Toronto) Prof. Aephraim Steinberg (University of Toronto)

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