Measurement Induced Dephasing and Suppression of Persistent Current in a Lattice Ring

TL;DR

This paper studies how continuous measurement affects the persistent current in a lattice ring with an Aharonov-Bohm flux, showing that measurement-induced dephasing can completely suppress the current.

Contribution

It provides an explicit analysis of measurement-induced dephasing effects on persistent current in a lattice ring coupled to a monitored quantum dot.

Findings

Persistent current is completely suppressed by measurement-induced dephasing.

Measurement acts as a which-way detector affecting quantum coherence.

Proposes practical experiments to observe measurement-induced dephasing.

Abstract

We investigate the effect of measurement on the persistent current density in a lattice ring penetrated by an Aharonov-Bohm flux and coupled to a quantum dot which is continuously monitored by a point contact detector. It is demonstrated by explicit analysis of the time-evolution of current density that the persistent current in the lattice ring is suppressed completely due to dephasing of quantum states induced by an analogous which-way-measurment that whether or not the electron is localized on the quantum dot. Practical experiments to observe the measurment induced dephasing is proposed.