Derivation of a -Symmetric Sine-Gordon Model from a Nonequilibrium Spin-Boson System via Keldysh Functional Integrals
This paper presents a microscopic derivation of a -symmetric non-Hermitian sine-Gordon effective theory from a nonequilibrium spin-boson system using Keldysh functional integrals, establishing a precise dictionary between microscopic parameters and effective couplings to demonstrate that the resulting renormalization group flow, exceptional point physics, and bound-state spectrum align with established non-Hermitian sine-Gordon results.