Quantum dynamics of wave packets in a nonstationary parabolic potential and the Kramers escape rate theory
| Autor: | Dubinko, Vladimir I., Laptev, Denis V., Mazmanishvili, Alexander S., Archilla, Juan F. R. |
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| Rok vydání: | 2016 |
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| Zdroj: | J. Micromech. Mol. Phys. 01(2) 1650010 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1142/S2424913016500107 |
| Popis: | At sufficiently low temperatures, the reaction rates in solids are controlled by quantum rather than by thermal fluctuations. We solve the Schr\"odinger equation for a Gaussian wave packet in a nonstation-ary harmonic oscillator and derive simple analytical expressions for the increase of its mean energy with time induced by the time-periodic modulation. Applying these expressions to the modified Kra-mers theory, we demonstrate a strong increase of the rate of escape out of a potential well under the time-periodic driving, when the driving frequency of the well position equals its eigenfrequency, or when the driving frequency of the well width exceeds its eigenfrequency by a factor of ~2. Such re-gimes can be realized near localized anharmonic vibrations (LAVs), in which the amplitude of atomic oscillations greatly exceeds that of harmonic oscillations (phonons) that determine the system tem-perature. LAVs can be excited either thermally or by external triggering, which can result in strong catalytic effects due to amplification of the Kramers rate Comment: 14 pages, 5 figures |
| Databáze: | arXiv |
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