Quantum measurement of an electron in disordered potential: delocalization versus measurement voltages

TL;DR

This paper investigates how quantum measurement via a quantum point contact affects an electron in a disordered potential, revealing new physics in measurement-induced delocalization and the role of measurement voltages.

Contribution

It extends previous work by analyzing measurement back-action on a multi-state electron system, highlighting new features of measurement-induced delocalization.

Findings

Measurement back-action cannot be fully described by Lindblad master equations.

Measurement voltages influence electron delocalization in disordered potentials.

New physical phenomena emerge from the interplay of measurement and disorder.

Abstract

Quantum point contact (QPC), one of the typical mesoscopic transport devices, has been suggested to be an efficient detector for quantum measurement. In the context of two-state charge qubit, our previous studies showed that the QPC's measurement back-action cannot be described by the conventional Lindblad quantum master equation. In this work, we study the measurement problem of a multi-state system, say, an electron in disordered potential, subject to the quantum measurement of the mesoscopic detector QPC. The effect of measurement back-action and the detector's readout current are analyzed, where particular attention is focused on some new features and the underlying physics associated with the measurement-induced delocalization versus the measurement voltages.