1. single-shot determination of quantum phases via continuous measurements

Aniket Patra

Aarhus University, Denmark

1 November 2022 Tue 4 pm

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     

We demonstrate that weak continuous probing may be exploited to determine and define quantum phases of complex many body systems based on the measurement record alone [1]. After deriving a stochastic Schroedinger equation for the experimental setup under consideration [2], 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.

[1] Aniket Patra, Lukas F. Buchmann, Felix Motzoi, Klaus Mølmer, Jacob Sherson, and Anne E. B. Nielsen, Single-shot determination of quantum phases via continuous measurements, Phys. Rev. A 106, 032215 (2022).

[2] Aniket Patra, Felix Motzoi, Anne E. B. Nielsen, and Klaus Mølmer, Stochastic Schroedinger equation for homodyne measurements of strongly correlated systems, to be published soon.