Nonlinear Interaction Strength in Polar Systems Enhances Quantum Coherence

Researchers Piotr Gładysz and Karolina Słowik have investigated the dynamics of polar systems coupled to classical external beams in the ultrastrong coupling regime. Their findings, published in the paper titled 'Rabi frequency for polar systems interacting with light,' reveal that the permanent dipole moments (PDMs) sustained by polar systems can couple to the electromagnetic field, leading to complex dynamics such as difference-frequency and harmonic generation. The study demonstrates that these dynamics can be simplified using a dynamic reference frame, resulting in a Jaynes-Cummings-like framework with effective parameters for frequency shift, coupling strength, and a rescaled relaxation rate. Notably, the interaction strength with the field amplitude shows a nonlinear dependence, which could enhance the coherence of quantum system ensembles with permanent dipoles. These insights may have significant implications for the development of more coherent quantum systems.