Single-shot determination of quantum phases via continuous measurements

We propose that weak continuous probing may be exploited to determine and define quantum phases of complex many-body systems based on the measurement record alone. We test the resulting phase criterion in numerical simulations of measurements on the Bose-Hubbard model and the quantum Ising chain. This yields a phase transition point in reasonable agreement with the quantum phase transition in the ground state of the closed system in the thermodynamic limit, despite the system being highly excited through the measurement dynamics. At high measurement strengths, the system's response enters a Zeno regime suppressing transitions between eigenstates of the measurement operator.

Automated summary

This article proposes the use of weak continuous probing to determine and define quantum phases in complex many-body systems. Through numerical simulations, the resulting phase criterion is tested and shows agreement with the quantum phase transition in the ground state of the closed system. The system's response enters a Zeno regime at high measurement strengths, suppressing transitions between eigenstates of the measurement operator.