Observation of the Decrease of Larmor Tunneling Times with Lower Incident Energy

Abstract

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 an auxiliary degree of freedom of the particle to clock the dwell time inside the barrier. We report on precise Larmor time measurements of ultra-cold ${}^{87}$Rb atoms tunneling through an optical barrier, which confirm longstanding predictions of tunneling times. We observe that atoms generally spend less time tunneling through higher barriers and that this time decreases for lower energy particles. For the lowest measured incident energy, at least $90\%$ of transmitted atoms tunneled through the barrier, spending an average of $0.59(2)$ms inside. This is $0.11(3)$ms faster than atoms traversing the same barrier with energy close to the barrier's peak and $0.21(3)$ms faster than when the atoms traverse a barrier with $23\%$ less energy.

Corrected typos, revised title to be consistent with journal version, results unchanged

References in corpus (1)

• Attoclock revisited on electron tunnelling time

Cited by in corpus (9)

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• Particle motion associated with wave function density gradients
• Proposal for a solid-state magnetoresistive Larmor quantum clock