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

Esin, Iliya and Romito, Alessandro and Blanter, Ya M. and Gefen, Yuval (2016) Crossover between strong and weak measurement in interacting many-body systems. New Journal of Physics, 18 (1): 013016. ISSN 1367-2630

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1409.4094v2 - Accepted Version
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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.