Investigating the Effects of the Interaction Intensity in a Weak Measurement

TL;DR

This paper investigates how the interaction strength influences the accuracy and effectiveness of weak measurement protocols in quantum mechanics, revealing a threshold that limits signal amplification even in the weak interaction regime.

Contribution

It provides an experimental analysis of the validity range of weak measurement protocols, specifically how interaction intensity constrains weak value extraction and amplification.

Findings

Interaction strength limits the range of achievable weak values.

A threshold exists beyond which signal amplification is constrained.

Weak measurement protocols are affected by coupling intensity even in the weak regime.

Abstract

Measurements are crucial in quantum mechanics, in fundamental research as well as in applicative fields like quantum metrology, quantum-enhanced measurements and other quantum technologies. In the recent years, weak-interaction-based protocols like Weak Measurements and Protective Measurements have been experimentally realized, showing peculiar features leading to surprising advantages in several different applications. In this work we analyze the validity range for such measurement protocols, that is, how the interaction strength affects the weak value extraction, by measuring different polarization weak values measured on heralded single photons. We show that, even in the weak interaction regime, the coupling intensity limits the range of weak values achievable, putting a threshold on the signal amplification effect exploited in many weak measurement based experiments.