Time Crystals, the quest for a new phase of matter
Mardi 19 octobre 2021 16:00
- Duree : 1 heure
Lieu : Visio-conférence Zoom
Orateur : Pedram ROUSHAN (Google)
La conférence est accessible sur Zoom : Visio-conférence Zoom
Résumé/Abstract :
Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC). Concretely, dynamical phases can be defined in periodically driven many-body localized systems via the concept of eigenstate order. In eigenstate-ordered phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, wherein few select states can mask typical behavior. Here [1] we implement a continuous family of tunable CPHASE gates on an array of superconducting qubits to experimentally observe an eigenstate-ordered DTC. We demonstrate the characteristic spatiotemporal response of a DTC for generic initial states. Our work employs a time-reversal protocol that discriminates external decoherence from intrinsic thermalization, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigen-spectrum. In addition, we locate the phase transition out of the DTC with an experimental finite-size analysis. Our results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors. 1. Mi et al, arXiv:2107.13571.
Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr
Prévenir un ami par email
Télécharger dans mon agenda