Entanglement dynamics of the ultra-strong coupling three-qubit Dicke model

TL;DR

This paper provides an analytical study of the entanglement dynamics in a three-qubit Dicke model under ultra-strong coupling, revealing unique revival patterns and robustness of the GHZ state.

Contribution

It introduces an analytical approach to describe three-qubit entanglement dynamics in the ultra-strong coupling regime, highlighting differences from simpler systems.

Findings

Three revival sequences produce a three-frequency beat note.

Explicit estimation of qubit-field and qubit-qubit entanglement dynamics.

GHZ state shows resistance to sudden death, indicating robustness.

Abstract

We give an analytical description of the dynamics of the three-qubit Dicke model using the adiabatic approximation in the parameter regime where the qubits transition frequencies are far off-resonance with the field frequency and the interaction strengths reach the ultra-strong coupling regimes. Qualitative differences arise when comparing to the single- and two-qubit systems - simple analytic formulas show that three revival sequences produce a three-frequency beat note in the time evolution of the population. We find an explicit way to estimate the dynamics for the qubit-field and qubit-qubit entanglement inside the three-qubit system in the ultra strong coupling regime, and the resistance to the sudden death proves the robustness of the GHZ state.