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arXiv:1604.06388 · Physical Review Letters

Interaction-Assisted Quantum Tunneling of a Bose-Einstein Condensate Out of a Single Trapping Well

Shreyas Potnis, Ramón Ramos, Kenji Maeda, Lincoln D. Carr, Aephraim M. Steinberg

Published Feb 10, 2017• 28 citations
arXivHTMLPDF

Abstract

We experimentally study tunneling of Bose-condensed ^{87}Rb atoms prepared in a quasibound state and observe a nonexponential decay caused by interatomic interactions. A combination of a magnetic quadrupole trap and a thin 1.3 μm barrier created using a blue-detuned sheet of light is used to tailor traps with controllable depth and tunneling rate. The escape dynamics strongly depend on the mean-field energy, which gives rise to three distinct regimes-classical spilling over the barrier, quantum tunneling, and decay dominated by background losses. We show that the tunneling rate depends exponentially on the chemical potential. Our results show good agreement with numerical solutions of the 3D Gross-Pitaevskii equation.

DOI
10.1103/physrevlett.118.060402

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We investigate macroscopic quantum tunneling of a Bose-Einstein condensate, and how it is affected by the interatomic interaction. We study the dynamics of a condensate falling under gravity and scattering on a Gaussian potential barrier that models a mirror formed by a far-detuned sheet of light. We observe bouncing, interference, and quantum tunneling of the condensate. We find that the tunneling rate is very sensitive to the interatomic interaction and to the shape of the condensate. Under many conditions the tunneling rate is strongly enhanced by the interaction as achieved, for instance, by increasing the number of condensed particles. In a quasi one-dimensional situation the tunneling pulse displays two peaks. The quantum tunneling can be quasiperiodic, and in this way one could generate coherent Bose-Einstein condensed atomic pulses.
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