Discriminating between the von Neumann and L\"uders reduction rule

TL;DR

This paper investigates methods to determine whether the von Neumann or L"uders state reduction rule applies during quantum measurements, using an unknown measurement apparatus and an ensemble in an unknown state.

Contribution

It proposes a procedure to distinguish between the von Neumann and L"uders measurement rules without detailed knowledge of the measurement device.

Findings

Method to test the applicable reduction rule using ensemble measurements

Framework for analyzing black-box measurement devices

Insights into the nature of quantum state collapse

Abstract

Given an ensemble of systems in an unknown state, as well as an observable $\hat A$ and a physical apparatus which performs a measurement of $\hat A$ on the ensemble, whose detailed working is unknown ('black box'), how can one test whether the L\"uders or von Neumann reduction rule applies?