Past of a quantum particle and weak measurement

TL;DR

This paper analyzes how weak measurements in a double Mach-Zehnder interferometer reveal the past of a quantum particle, showing that weak values influence interference and align with standard quantum mechanics.

Contribution

It demonstrates that weak measurement traces are consistent with quantum mechanics and clarifies misconceptions about the particle's past in interferometry.

Findings

Weak values affect quantum interference patterns.

Results align with standard quantum mechanics.

Weak measurement traces do not contradict conventional theory.

Abstract

We present an analysis of a double Mach-Zehnder interferometer in which an ensemble of identical pre- and postselected particles leave a weak trace. A knowledge of the weak value partially destroys the quantum interference. The results, contrary to some recent claims, are in accordance with the usual quantum mechanical expectations.