Vestnik of Samara University Natural Science Series

Dynamics of entanglement of separable three-qubit states in the Tavis — Cummings multiphoton model

A. R. Bagrov, E. K. Bashkirov

Published Dec 11, 2025• 0 citations

Abstract

In this work we study in detail the generalized Tavis — Cummings model, in which three identical qubits are trapped in a lossless single-mode resonator and interact resonantly with the quantized thermal electromagnetic field of this resonator by means of multiphoton processes. An exact solution of the unsteady Schr¨odinger equation for separable qubit states and Fock states of the resonator field was demonstrated for the model under study. The resulting expressions were used to calculate the density matrix in the case of the thermal field of the resonator and to calculate the criterion for pairwise entanglement of qubits — Wootters concurrence. The results showed that the thermal field can induce pairwise entanglement between qubits for all initial separable states for certain system parameters. The calculations also showed that the photon multiple can be considered as an effective mechanism for controlling the entanglement of qubits, since its increase leads to a significant suppression of the effect of the sudden death of entanglement and to an increase in the maximum degree of entanglement for some separable qubit states.

DOI: 10.18287/2541-7525-2025-31-2-7-21

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