Petersen Jakob, Pollak Eli
Chemical Physics Department, Weizmann Institute of Science , 76100 Rehovoth, Israel.
J Phys Chem Lett. 2017 Sep 7;8(17):4017-4022. doi: 10.1021/acs.jpclett.7b02018. Epub 2017 Aug 15.
Attosecond ionization experiments have not resolved the question "What is the tunneling time?". Different definitions of tunneling time lead to different results. Second, a zero tunneling time for a material particle suggests that the nonrelativistic theory includes speeds greater than the speed of light. Chemical reactions, occurring via tunneling, should then not be considered in terms of a nonrelativistic quantum theory calling into question quantum dynamics computations on tunneling reactions. To answer these questions, we define a new experimentally measurable paradigm, the tunneling flight time, and show that it vanishes for scattering through an Eckart or a square barrier, irrespective of barrier length or height, generalizing the Hartman effect. We explain why this result does not lead to experimental measurement of speeds greater than the speed of light. We show that this tunneling is an incoherent process by comparing a classical Wigner theory with exact quantum mechanical computations.
阿秒电离实验尚未解决“隧穿时间是多少？”这一问题。隧穿时间的不同定义会导致不同的结果。其次，物质粒子的零隧穿时间表明非相对论理论包含了大于光速的速度。那么，通过隧穿发生的化学反应就不应依据质疑隧穿反应量子动力学计算的非相对论量子理论来考虑。为了回答这些问题，我们定义了一种新的可通过实验测量的范式——隧穿飞行时间，并表明无论势垒长度或高度如何，通过埃卡特势垒或方形势垒散射时它都为零，这推广了哈特曼效应。我们解释了为什么这个结果不会导致对大于光速的速度进行实验测量。通过将经典维格纳理论与精确的量子力学计算进行比较，我们表明这种隧穿是一个非相干过程。
