Topological quantization of current in quantum tunnel contacts

TL;DR

This paper demonstrates that incorporating the Berry phase and dissipative effects in the effective action of quantum tunnel contacts leads to a topologically induced quantization of tunnel current at low temperatures, controllable via gate voltage.

Contribution

It introduces a topological approach to quantize tunnel current without relying on capacitive charging energy, linking the Berry phase to current control in quantum contacts.

Findings

Quantization of tunnel current induced by Berry phase and dissipation.

Current control via gate voltage through topological effects.

Potential application in quantum device design.

Abstract

It is shown that an account of the Berry phase (a topological $\theta$-term) together with a dissipative term in the effective action $S[\phi]$ of the tunnel contacts induces a strong quantization of the tunnel current at low temperatures. This phenomenon like the Coulomb blockade reflects a discrete charge structure of the quantum shot noise and can ensure a quantization of the tunnel current without a capacitive charging energy $E_C$, when the latter is strongly suppressed by quantum fluctuations. Since a value of the $\theta$-parameter is determined by the gate voltage, this effect allows to control a current through the contact. A possible physical application of this effect is proposed.