Time-dependent exchange and tunneling: detection at the same place of two electrons emitted simultaneously from different sources

TL;DR

This paper investigates how exchange interactions affect two-electron tunneling probabilities, revealing non-zero detection probabilities at the same location, which challenges traditional assumptions in quantum tunneling scenarios.

Contribution

It demonstrates that exchange interactions lead to non-zero two-electron detection probabilities at the same side of a barrier, even with common initial states, extending understanding of quantum tunneling.

Findings

Non-zero two-electron detection probabilities at the same side of the barrier.

Orthogonal transmitted and reflected components can reproduce distinguishable particle probabilities.

Implications for quantum noise evaluation in mesoscopic systems.

Abstract

Two-particle scattering probabilities in tunneling scenarios with exchange interaction are analyzed with quasi-particle wave packets. Two initial one-particle wave packets (with opposite central momentums) are spatially localized at each side of a barrier. After impinging upon a tunneling barrier, each wave packet splits into transmitted and reflected components. When the initial two-particle anti-symmetrical state is defined as a Slater determinant any type of (normalizable) one-particle wave packet, it is shown that the probability of detecting two (identically injected) electrons at the same side of the barrier is different from zero in very common (single or double barrier) scenarios. In some particular scenarios, the transmitted and reflected components become orthogonal and the mentioned probabilities reproduce those values associated to distinguishable particles. These unexpected non-zero probabilities are still present when non-separable Coulomb interaction or non-symmetrical potentials are considered. On the other hand, for initial wave packets close to Hamiltonian eigenstates, the usual zero two-particle probability for electrons at the same side of the barrier found in the literature is recovered. The generalization to many-particle scattering probabilities with quasi-particle wave packets for low and high phase-space density are also analyzed. The far-reaching consequences of these non-zero probabilities in the accurate evaluation of quantum noise in mesoscopic systems are briefly indicated.