Tunneling time in fluctuating symmetric double wells: Suppression and enhancement of tunneling by spatial symmetry-preserving perturbations

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• 作者：Susmita Kar^a ; S.P. Bhattacharyya ; ^a ; ^{pcspb@iacs.res.in}
• 关键词：Fluctuating symmetric double-well potential ; Tunneling dynamics ; Tunneling enhancement and suppression ; Coherent destruction of tunneling ; Symmetry preserving fluctuation ; Control of tunneling ; Barrier localization and dynamic localization
• 刊名：Chemical Physics
• 出版年：2011
• 出版时间：24 January 2011
• 年：2011
• 卷：379
• 期：1-3
• 页码：23-32
• 全文大小：2661 K

文摘

We investigate how tunneling-time gets affected by spatial symmetry preserving fluctuations in the parameters determining the width, barrier height and well-depth of a symmetric double-well potential. Sinusoidal and rectified sinusoidal fluctuations of the well-parameters are shown to have contrasting effects. Significant enhancement of tunneling is noticed when the well-parameters fluctuate sinusoidally with frequency ω ≈ ω₀ while under rectified sinusoidal perturbation, quenching of tunneling takes place at a fluctuation frequency , being the frequency of the lowest transition allowed by the fluctuation induced spatial perturbation of even parity. Time-dependent Hellmann–Feynman theorem is invoked to analyze the energy changes induced by fluctuations. It turns out that the enhancement of tunneling in the sinusoidally fluctuating double well at frequency ω ≈ ω₀ is caused by transition to 1^± levels under the barrier while in the rectified sinusoidal field at , a two-photon like process suppresses the tunneling by inducing barrier localization.