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arXiv 2210.04564cond-mat.mes-hall
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势垒隧穿中的时间反转态

Time Reversed States in Barrier Tunneling

Kanchan Meena, P. Singha Deo

摘要:

隧道,虽然是一个物理现实,却笼罩在神秘之中。在势垒下不能构造波包,群速度不能定义。隧穿粒子可以在势垒的两侧观察到,但由于与量子测量有关的几个问题,它在势垒下的性质从未被探测过。我们表明,有办法绕过这些问题的介观系统,甚至可以推导出一个表达式的量子力学下的障碍。一个通用的计划,推导出这个表达式的任何任意系统。人们可以用介观现象来对表达式进行几次理论和实验的交叉检验。为了演示,我们考虑一个理想的一维量子环Aharonov-Bohm通量$Φ$,连接到一个水库。它给出了明确的证据,即传播发生在屏障下,导致可以非侵入性地测量和理论上交叉检查的电流。时间反转状态起作用,但没有违反因果关系的证据。已知倏逝态在很大程度上是稳定的,并且对相位波动具有鲁棒性,使得它们成为器件应用的可能候选者,因此将势垒下的电流形式化是重要的。

英文摘要:

Tunneling, though a physical reality, is shrouded in mystery. Wave packets cannot be constructed under the barrier and group velocity cannot be defined. The tunneling particle can be observed on either sides of the barrier but its properties under the barrier has never been probed due to several problems related to quantum measurement. We show that there are ways to bypass these problems in mesoscopic systems and one can even derive an expression for the quantum mechanical current under the barrier. A general scheme is developed to derive this expression for any arbitrary system. One can use mesoscopic phenomenon to subject the expression to several theoretical and experimental cross checks. For demonstration we consider an ideal 1D quantum ring with Aharonov-Bohm flux $Φ$, connected to a reservoir. It gives clear evidence that propagation occur under the barrier resulting in a current that can be measured non-invasively and theoretically cross checked. Time reversed states play a role but there is no evidence of violation of causality. The evanescent states are known to be largely stable and robust against phase fluctuations making them a possible candidate for device applications and so formalizing current under barrier is important.

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