Testing precision and accuracy of weak value measurements in an IBM quantum system

TL;DR

This paper investigates the measurement of weak values in an IBM quantum system, demonstrating that varying measurement strengths can be used, but stronger measurements do not always outperform weaker ones.

Contribution

It extends previous neutron interferometry schemes to optical and quantum computing systems, showing how to measure weak values across different measurement strengths.

Findings

Weak values can be measured with varying performance in quantum systems.

Strong measurements do not always outperform weak measurements in this context.

Implementation in IBM quantum computers confirms the feasibility of measuring weak values.

Abstract

Historically, weak values have been associated with weak measurements performed on quantum systems. Over the past two decades, a series of works have shown that weak values can be determined via measurements of arbitrary strength. One such proposal by Denkmayr et al. [Phys. Rev. Lett. 118, 010402 (2017)], carried out in neutron interferometry experiments, yielded better outcomes for strong than for weak measurements. We extend this scheme and explain how to implement it in an optical setting as well as in a quantum computational context. Our implementation in a quantum computing system provided by IBM confirms that weak values can be measured, with varying degrees of performance, over a range of measurement strengths. However, at least for this model, strong measurements do not always perform better than weak ones.