Séminaire du LPTMS : Marco Schiro’ (College de France)

Quantum Measurements, Entanglement and Stochastic Resetting

Marco Schiro’ (College de France)

Hybrid: onsite seminar + zoom.
https://cnrs.zoom.us/j/92257465037?pwd=djU4YVYrNlU3K1JpNy9FZzF4eWp3UT09

Meeting ID: 922 5746 5037
Passcode: HjA4r4

I will discuss the problem of a quantum many-body system evolving under its own Hamiltonian and subject to local weak quantum measurements. The resulting quantum many-body trajectories evolve according to a stochastic Schrodinger equation. Averaging the wave function over the realisations of the stochastic process gives rise to a mixed state evolution for the system density matrix whic leads to heating and featureless steady states. However, hidden in the random fluctuations of the measurement process there is a much richer physics – with new dynamical phases characterised by qualitatively different entanglement properties and sharp phase transitions between them – which has started to be explored only very recently. I will discuss this measurement-induced criticality in the context of a Quantum Ising Chain, which I will show to display a transition from a critical phase with logarithmic scaling of the entanglement entropy to an area-law phase corresponding to the onset of the Quantum Zeno Effect. I will interpret these results using a phenomenological quasiparticle picture for entanglement dynamics in monitored systems based on stochastic resetting.

Date/Time : 25/04/2023 - 11:00 - 12:00

Location : Salle des séminaires du FAST et du LPTMS, bâtiment Pascal n°530