IQIM Postdoctoral and Graduate Student Seminar

Abstract: Measurements allow efficient preparation of interesting quantum many-body states with long-range entanglement, with immediate application to current quantum processors. In this talk, we show how critical states can be prepared via shallow quantum circuits and measurements. In the simplified scenario allowing post-selection, the equal-time correlators of the prepared states are described by correlation functions of certain classical statistical models at finite temperature, and feature spatial conformal invariance. This establishes an exact correspondence between the measurement-prepared critical states and conformal field theories of a range of critical spin models, including familiar Ising models and gauge theories. Without post-selection, the correspondence is extended to that between the ensemble of measured quantum states and the ensemble of thermal states of classical models with disorder, such as the random-bond Ising model. Critical points belonging to unusual universality classes now arise naturally, such as Nishimori criticality.

This talk is based on arXiv:2208.11699 with Jong Yeon Lee, Zhen Bi and Matthew Fisher.

Lunch will be provided, following the talk, on the lawn north of the Bridge Building.