Pollak Eli
Chemical Physics Department, Weizmann Institute of Science , 76100 Rehovoth, Israel.
J Phys Chem Lett. 2017 Jan 19;8(2):352-356. doi: 10.1021/acs.jpclett.6b02692. Epub 2017 Jan 3.
The standard approaches to tunneling times are replaced by considering time correlation functions. A class of correlation functions that is always positive is identified and used to define quantum mechanical transition time probability distributions. The formalism is used to study the quantum dynamics of a thermal position correlation function of a parabolic barrier Hamiltonian. The transition time probability distribution between two points distributed symmetrically about the barrier top shifts to shorter times as the temperature is reduced and tunneling is increased. A study of the mean transition time as a function of the distance between the center of the initial and final densities shows that when the temperature is sufficiently low and tunneling dominates the dynamics, increasing the length of the path traversed decreases the mean transition time. The introduction of friction to the dynamics does not "destroy" this phenomenon, except when the friction coefficient is very large.
通过考虑时间关联函数，隧穿时间的标准方法被取代。一类始终为正的关联函数被识别出来，并用于定义量子力学跃迁时间概率分布。该形式体系被用于研究抛物线势垒哈密顿量的热位置关联函数的量子动力学。随着温度降低和隧穿增加，关于势垒顶部对称分布的两点之间的跃迁时间概率分布向更短时间偏移。对平均跃迁时间作为初始和最终密度中心之间距离的函数的研究表明，当温度足够低且隧穿主导动力学时，增加所穿越路径的长度会减少平均跃迁时间。向动力学中引入摩擦力并不会“破坏”这一现象，除非摩擦系数非常大。
