Optimality of Lindblad unfolding in measurement phase transitions

Abstract

Entanglement phase transitions in hybrid quantum circuits describe individual quantum trajectories rather than the measurement-averaged ensemble, despite the fact that results of measurements are not conventionally used for feedback. Here, we numerically demonstrate that a class of generalized measurements with identical measurement-averaged dynamics give different phases and phase transitions. We show that measurement-averaged destruction of Bell state entanglement is a useful proxy for determining which hybrid circuit yields the lowest-entanglement dynamics. We use this to argue that no unfolding of our model can avoid a volume law phase, which has implications for simulation of open quantum systems.

Published version

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Cited by in corpus (6)

• Many-Body Open Quantum Systems
• Efficient sampling of noisy shallow circuits via monitored unraveling
• Optimized trajectory unraveling for classical simulation of noisy quantum dynamics
• Telling different unravelings apart via nonlinear quantum-trajectory averages
• Analog simulation of noisy quantum circuits
• Classical simulation of noisy quantum circuits via locally entanglement-optimal unravelings