Crossover between strong and weak measurement in interacting many-body systems

TL;DR

This paper investigates the transition from weak to strong measurement regimes in many-body electronic systems, revealing oscillatory behavior in the generalized conditional value due to many-body effects, observable via current correlations.

Contribution

It introduces a generalized conditional value for many-body systems and characterizes its oscillatory crossover between measurement regimes, highlighting many-body effects.

Findings

GCV exhibits oscillations depending on interaction strength.

Oscillations are a genuine many-body effect.

Oscillations can be observed through voltage-dependent current correlations.

Abstract

Measurements with variable system-detector interaction strength, ranging from weak to strong, have been recently reported in a number of electronic nanosystems. In several such instances many-body effects play a significant role. Here we consider the weak--to--strong crossover for a setup consisting of an electronic Mach-Zehnder interferometer, where a second interferometer is employed as a detector. In the context of a conditional which-path protocol, we define a generalized conditional value (GCV), and determine its full crossover between the regimes of weak and strong (projective) measurement. We find that the GCV has an oscillatory dependence on the system-detector interaction strength. These oscillations are a genuine many-body effect, and can be experimentally observed through the voltage dependence of cross current correlations.