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arXiv:2509.05704 · Physical Review A

Tunneling of bosonic qubits under local dephasing through a microscopic approach

Alberto Ferrara, Farzam Nosrati, Andrea Smirne, Jyrki Piilo, Rosario Lo Franco

Published Jun 17, 2026• 0 citations
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Abstract

We present a microscopic derivation of a master equation for two-component bosons (bosonic qubits) which tunnel between spatially separated modes under local dephasing noise. Starting from the full system-bath Hamiltonian with Lorentzian coupling distributions, we analytically obtain a time-local master equation whose structure reveals intrinsic non-Markovian features and recovers the standard phenomenological dephasing model in the short-time limit. Comparison with exact pseudomode simulations confirms its validity beyond weak-coupling and Markovian regimes. We identify a resonance condition between tunneling and bath frequencies for which dephasing drives the system toward correlated steady states, stabilizing coherence and entanglement instead of suppressing them. These results establish a rigorous microscopic foundation for dephasing models in bosonic tunneling systems and reveal a noise-induced mechanism for steady-state entanglement.

DOI
10.1103/f2sy-sj27

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We present a microscopic derivation of a master equation for two bosonic qubits tunneling between spatially separated modes under local dephasing, described by a Lorentzian spectrum. The resulting time-local equation reveals intrinsic non-Markovian features. When the bath central frequency is resonant with the tunneling amplitude, dephasing can drive the system toward a correlated steady state that sustains coherence and entanglement, as opposed to complete decoherence predicted by white noise models. These results provide a rigorous foundation for pure dephasing in bosonic tunneling systems and demonstrate how structured noise can actively generate steady-state quantum correlations.
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