Few-fermion resonant tunneling and underbarrier trapping in asymmetric potentials

TL;DR

This paper investigates how inter-particle interactions in few-fermion systems induce asymmetric tunneling through asymmetric potentials, revealing regimes of resonant trapping and many-body effects that differ from single-particle tunneling.

Contribution

It demonstrates that interactions break tunneling symmetry in asymmetric potentials and identifies regimes of under-barrier resonant trapping and many-body resonant tunneling.

Findings

Inter-particle interactions cause asymmetric tunneling in fermions.

Spin configuration affects tunneling symmetry, with triplet states preserving symmetry.

Interactions enable under-barrier resonant trapping and many-body tunneling.

Abstract

Understanding quantum tunneling in many-body systems is crucial for advancing quantum technologies and nanoscale device design. Despite extensive studies of quantum tunneling, the role of interactions in determining directional transport through asymmetric barriers in discrete quantum systems remains unclear. Here we show that noninteracting fermions exhibit symmetric tunneling probabilities regardless of barrier orientation, while inter-particle interactions break this symmetry and create pronounced asymmetric tunneling behavior. We explore the dependence of tunneling behavior on the initial spin configurations of two spin-1/2 fermions: spin-triplet states preserve tunneling symmetry, while spin-singlet states show strong asymmetry. We identify regimes where interactions mediate tunneling through under-barrier resonant trapping and enhance tunneling via many-body resonant tunneling -- a phenomenon arising solely from inter-particle interactions and being fundamentally different from traditional single-particle resonant tunneling. Our results may be applied to the design of nanoscale devices with tailored transport properties, such as diodes and memristors.