Abstract

The Kibble–Zurek scaling describes the driven critical dynamics starting with an equilibrium state far away from the critical point. Recently, it has been shown that scaling behaviors also exist when the fluctuation term changes starting near the critical point. In this case, the relevant initial conditions should be included in the scaling theory as additional scaling variables. Here, we study the driven quantum critical dynamics in which a symmetry-breaking field is linearly changed starting from the vicinity of the critical point. We find that, similar to the case of changing the fluctuation term, scaling behaviors in the driven dynamics can be described by the Kibble–Zurek scaling with the initial symmetry-breaking field being included as its additional scaling variable. Both the cases of zero and finite temperatures are considered, and the scaling forms of the order parameter and the entanglement entropy are obtained. We numerically verify the scaling theory by taking the quantum Ising model as an example.

Highlights

  • Recent experimental progress made in cold-atom systems has led to many studies on the nonequilibrium behaviors in quantum many-body systems [1,2,3]

  • The energy gap is very large, the excitation induced by the external driving can be ignored, and the system evolves adiabatically along the equilibrium state; when the system is near its critical point, the gap becomes smaller and cannot suppress the excitations induced by the external driving, and the system is in an impulse stage in which the external driving dominates

  • In contrast to previous studies, in which the fluctuation term is changed from the vicinity of the critical point [35,36,37,38], here we study the quantum driven critical dynamics by changing a symmetry-breaking field starting with an equilibrium state near the critical point

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Summary

Introduction

Recent experimental progress made in cold-atom systems has led to many studies on the nonequilibrium behaviors in quantum many-body systems [1,2,3]. The initial condition will affect the driven dynamics This inspires many studies on how to generalize the Kibble–Zurek mechanism to take the effects induced by the initial conditions into account in both classical and quantum phase transitions [33,34,35,36,37,38].

Kibble–Zurek Scaling and Its Generalization
Model and Numerical Method
Numerical Results
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At evolution of Sis shown under decreasing
Summary and Discussion
Quantum
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