The ability to tune quantum tunneling is key for achieving selectivity in manipulation of individual particles in quantum technology applications. In this work we count electron escape events out of a time-dependent confinement potential, realized as a dynamic quantum dot in a GaAs/AlGaAs heterostructure. A universal scaling relation of the escape probability as a function of potential barrier rise time and depth is established and developed as a method to probe tunneling rates over many orders of magnitude reaching the limit of shallow anharmonic confinement. Crossover to thermally activated transport is used to estimate the single time-energy scale of the universal model. In application to metrological single electron sources, in-situ calibrated control signals greatly extend the accessible dynamical range for probing the quantization mechanism. Validation of the cubic potential approximation sets a foundation for microscopic modeling of quantum tunneling devices in the shallow confinement regime.
Effective Hamiltonian model for helically constrained quantum systems within adiabatic perturbation theory: application to the Chirality-Induced Spin Selectivity (CISS) Effect
手性诱导的自旋选择性（CISS）效应已被实验证实为一大类有机分子。对这种效应进行精确建模仍然是一项具有挑战性的任务，现象学模型和第一原理模拟都产生了不确定的结果。在K. Michaeli和R. Naaman（J. Phys. Chem C 123，17043（2019））我们系统地研究了一个有效的一维模型，该模型是作为具有强约束并包括自旋轨道耦合的三维量子系统的极限而导出的。具有简单的分析结构，这样的模型可以被认为是一个最小的设置自旋相关的影响的描述。我们使用绝热微扰理论提供了一个数学上健全的近似程序适用于一大类自旋相关的连续模型。我们利用模型的简单性，通过分析其结构，以获得更好的理解如何发生和自旋极化效应的大小与模型的参数和几何形状。
