Macroscopic Quantum Tunneling Effect of Z2 Topological Order

TL;DR

This paper investigates the macroscopic quantum tunneling effect in Z2 topological order within the Wen-Plaquette model, analyzing ground state energy splitting through perturbation theory and confirming results with exact diagonalization.

Contribution

It introduces a high-order degenerate perturbation approach to derive effective pseudo-spin models for Z2 topological order, providing new insights into quantum tunneling phenomena.

Findings

Energy splitting of ground states calculated

Results consistent with exact diagonalization

Enhanced understanding of MQT in topological systems

Abstract

In this paper, macroscopic quantum tunneling (MQT) effect of Z2 topological order in the Wen-Plaquette model is studied. This kind of MQT is characterized by quantum tunneling processes of different virtual quasi-particles moving around a torus. By a high-order degenerate perturbation approach, the effective pseudo-spin models of the degenerate ground states are obtained. From these models, we get the energy splitting of the ground states, of which the results are consistent with those from exact diagonalization method