Measurement altered Ising criticality

Time: Apr 30th, 10am – 11am

Location:  W M. Keck Computational Materials Theory Center Room 1310 – Live Oak

Speaker: Yue Liu, Caltech (Jason Alicea's group)

Title: Measurement altered Ising criticality

Abstract: Measurement has been useful to manipulate and prepare quantum many-body states. We study the effect of weak measurement on a critical Ising chain, where a chain of ancilla is coupled to the critical chain and then projectively measured. With field-theoretical calculations and extensive numerical simulations, we show that when the measurement leads to a marginal perturbation, the correlations and effective central charge depend continuously on the measurement strength; while for measurement that corresponds to a relevant perturbation, the post-measurement wavefunction exhibits both power-law decaying correlations and area-law entanglement scaling. We also extend this analysis to the tri-critical Ising chain where an intermediate fixed point appears when the measurement basis is tilted. Finally, we discuss possible realization of this protocol with Rydberg atom arrays.