Probing excited-state quantum phase transition in a quantum many body system via out-of-time-ordered correlator

Understand

As a measure of information scrambling and quantum chaos, out-of-time-ordered correlator (OTOC) plays more and more important role in many different fields of physics.

• In this work, we verify that the OTOC can also be used as a prober of the excited-state quantum phase transition (ESQPT) in a quantum many body system.
• By using the exact diagonalization method, we examine the dynamical properties of OTOC in the Lipkin model, which undergoes an ESQPT.
• We demonstrate that the OTOC exhibits a remarkable distinct evolution behaviors in different phases of ESQPT.