Revival times at quantum phase transitions

TL;DR

This paper investigates quantum revival phenomena in many-body systems near quantum phase transitions, revealing how revival times diverge and scale with system size as the critical point is approached.

Contribution

It extends the concept of quantum revivals to many-body systems and analyzes their behavior near quantum critical points using two models.

Findings

Revival times are proportional to system size away from criticality.

Near the critical point, revival times diverge as a power law.

Scaling of revival times becomes nonlinear at the critical point.

Abstract

The concept of quantum revivals is extended to many-body systems and the implications of traversing a quantum phase transition are explored. By analyzing two different models, the vibron model for the bending of polyatomic molecules and the Dicke model for a quantum radiation field interacting with a system of two-level atoms, we show evidence of revival behavior for wave packets centered around energy levels as low as the fundamental state. Away from criticality, revival times exhibit smooth, nonsingular behavior, and are proportional to the system size. Upon approaching a quantum critical point, they diverge as a power law and scale with the system size, although the scaling is no longer linear.