We investigate the steady-state dynamics of two coupled cavities with balanced gain and loss in the presence of parametric driving using the Schwinger-Keldysh functional formalism. This approach allows us to analyze the non-Hermitian dynamics and evaluate steady-state observables associated with nonclassical behavior. We show that a parametric drive breaks the exact $\mathcal{PT}$ symmetry of the system and acts as a control parameter that induces a population imbalance between the cavities. The interplay of coherent tunneling, balanced loss and gain, and two-photon driving gives rise to a pronounced population imbalance between the cavities that tends to a limiting value for strong dissipation. This signals a drive-induced localization and Zeno-like suppression of photon distribution. Intermode quantum correlations are characterized using entanglement negativity, revealing a drive-dependent threshold for entanglement generation and the occurrence of entanglement sudden death at finite dissipation. In addition, near the exceptional points the system becomes sensitive to fluctuations, resulting in the minimum of the steady-state purity. The presence of the parametric drive modifies this behavior by lifting the non-Hermitian spectral degeneracy and altering the steady-state coherence properties of the system. Our results demonstrate how parametric driving provides a versatile mechanism for controlling localization, quantum correlations, and fluctuation properties in driven-dissipative non-Hermitian systems.

Close

PrevNext

View figure in article

• Quantum optics