Entanglement Evolution of Noisy Quantum Systems: Master Equation-TFD Solutions

In this paper, Thermofield Dynamics (TFD) is applied to map a quantum optics nonlinear master equation into a Schrodinger-like equation for any arbitrary initial condition. This formalism provides a more efficient way for solving open quantum system problems. Then we use the Hartree-Fock approximation to solve the master equations of two separate noisy quantum systems analytically, which allows us to analyze the entanglement and quantum mutual information in each case using the eigenvalues of a covariance matrix, followed by two-mode and single-mode squeezed states.

💡 Research Summary

The paper presents a systematic approach to solving nonlinear quantum master equations by exploiting Thermo‑Field Dynamics (TFD). In the TFD framework the density operator ρ is represented as a state vector |ρ⟩ = ρ̂|I⟩ in an enlarged Hilbert space H⊗H̃, where |I⟩ = ∑ₙ|n, ˜n⟩ is the thermal vacuum. By acting with |I⟩ on the conventional master equation ∂ₜρ = −i