Transient Dynamics of a Driven Quantum Bistable System

Paul W. Brumer

Ramarao Inguva, Charles M. Bowden

Dynamical transient response and longitudinal spatial evolution of the first-order phase transition are presented for intrinsic optical bistability of a system of interacting spatially distributed, coherently driven two-level atoms. It is shown that a discontinuity in the nonlinear dielectric function is established internal to the medium due to transient response to a coherent, externally applied, time-dependent driving field, following the attainment of a critical value for the input intensity. If the externally applied field intensity reaches the steady state, beyond the critical value, the discontinuity of the nonlinear dielectric function in the medium reaches a stable stationary condition and forms a spatial boundary between states of high and low polarization in the medium. Thus it is shown that intrinsic optical bistability corresponds to a spatial as well as a temporal first-order phase transition in light-matter interactions, far from thermodynamic equilibrium, where the spatial boundary between different phases is established by transient dynamical response to the incident field.

D. C. Hutcgings

Szu-Cheng Cheng, Ting-Wei Chen

We investigate the influence of transverse-electric–transverse-magnetic (TE–TM) splitting on the nonlinear response and bistability of resonantly driven spinor exciton-polaritons in a spatially homogeneous microcavity system. Using a coupled exciton–photon mean-field model, we find that TE–TM splitting significantly modifies the bistability threshold, hysteresis width, and spin composition of the steady states. In particular, TE–TM splitting counteracts the spin imbalance imposed by elliptically polarized pumping, leading to nearly equal populations of the two spin components and strongly suppressed degree of circular polarization in the steady state. The pump momentum plays a crucial role through its connection to the curvature of the lower polariton dispersion, resulting in distinct nonlinear regimes with different switching thresholds and dynamical responses. The intermediate branch within the hysteresis loop is unstable but may exhibit slow instability growth rates, giving rise to long-lived transient states. These results clarify how TE–TM splitting reshapes bistability and nonlinear spin dynamics in polariton systems and provide insight into the controlling polariton switching behavior through cavity anisotropy and pump parameters.

M. I. Dykman

Xinfu Xia, Xiao-shen Li, D. L. Lin +1 more

Transient behavior in the optical bistability mediated by phonon-mode and virtual-exciton coupling is studied for an electron-phonon-coupling system, such as polydiacetylene toluene sulfonate. Numerical calculations are used to analyze the evolution between bistable states, and switching behavior and Rabi oscillations are found.