The effects of amplification of fluctuation energy scale by quantum measurement choice on quantum chaotic systems: Semiclassical analysis

Measurement choices in weakly-measured open quantum systems can affect quantum trajectory chaos. We consider this scenario semi-classically and show that measurement acts as nonlinear generalized fluctuation and dissipation forces. These can alter effective dissipation in the quantum spread variables and hence change the dynamics, such that measurement choices on the coupled quantum dynamics can enhance quantum effects and make the dynamics chaotic, for example. This analysis explains the measurement-dependence of quantum chaos at a variety of parameter settings, and in particular we demonstrate quantitatively that the choice of monitoring scheme can be more relevant than system scale $\beta$ in determining the `quantumness' of the system.