Control and manipulation of quantum engineered systems allows for the utilization of time-dependent parametric modulations for accessing novel out-of-equilibrium phenomena. In the absence of such driving, the dissipative Dicke model exhibits a fascinating out-of-equilibrium many-body phase transition as a function of a coupling between a driven photonic cavity and numerous two-level atoms. We study the effect of a parametric modulation of this coupling and discover a rich phase diagram as a function of the modulation strength. We find that in addition to the established normal and super-radiant phases, a new phase with pulsed superradiance, which we term dynamical normal phase, appears when the system is parametrically driven. Employing different methods, we characterize the different phases and the transitions between them. Specific heed is paid to the role of dissipation in determining the phase boundaries. Our analysis paves the road for the experimental study of dynamically stabilized phases of interacting light and matter.
Control and manipulation of quantum engineered systems allows for the utilization of time-dependent parametric modulations for accessing novel out-of-equilibrium phenomena. In the absence of such driving, the dissipative Dicke model exhibits a fascinating out-of-equilibrium many-body phase transition as a function of a coupling between a driven photonic cavity and numerous two-level atoms. We study the effect of a parametric modulation of this coupling and discover a rich phase diagram as a function of the modulation strength. We find that in addition to the established normal and super-radiant phases, a new phase with pulsed superradiance, which we term dynamical normal phase, appears when the system is parametrically driven. Employing different methods, we characterize the different phases and the transitions between them. Specific heed is paid to the role of dissipation in determining the phase boundaries. Our analysis paves the road for the experimental study of dynamically stabilized phases of interacting light and matter.
We investigate the three-level Dicke model, which describes a fundamental class of light-matter systems. We determine the phase diagram in the presence of dissipation, which we assume to derive from photon loss. Utilizing both analytical and numerical methods we characterize the incommensurate time crystalline, light-induced, and light-enhanced superradiant states in the phase diagram for the parametrically driven system. As a primary application, we demonstrate that a shaken atom-cavity system is naturally approximated via a parametrically driven dissipative three-level Dicke model.
We establish a new theoretical framework, based on a time-dependent mean field approach, to address the dynamics of the driven Dicke model. The joint evolution of both mean fields and quantum fluctuations gives rise to a rich and generally non-linear dynamics, featuring a normal (stable) regime and an unstable, super-radiant one. Various dynamical phenomena emerge, such as the spontaneous amplification of vacuum fluctuations, or the appearance of special points around which the mean-field amplitudes rotate during driven time evolution, signalling a dynamical symmetry breaking. We also provide a characterization of the driving-induced photon production in terms of the work done by the driving agent, of the non-adiabaticity of the process and of the entanglement generated between the atomic system and the cavity mode.
We investigate the three-level Dicke model, which describes a fundamental class of light-matter systems. We determine the phase diagram in the presence of dissipation, which we assume to derive from photon loss. Utilizing both analytical and numerical methods we characterize incommensurate time crystalline states in this phase diagram, as well as light-induced and light-enhanced superradiant states. As a primary application, we demonstrate that a shaken atom-cavity system is naturally approximated via a parametrically driven open three-level Dicke model.
The Dicke model is a paradigmatic quantum-optical model describing the interaction of a collection of two-level systems with a single bosonic mode. Effective implementations of this model made it possible to observe the emergence of superradiance, i.e., cooperative phenomena arising from the collective nature of light-matter interactions. Via reservoir engineering and analogue quantum simulation techniques, current experimental platforms allow us not only to implement the Dicke model but also to design more exotic interactions, such as the two-photon Dicke model. In the Hamiltonian case, this model presents an interesting phase diagram characterized by two quantum criticalities: a superradiant phase transition and a spectral collapse, that is, the coalescence of discrete energy levels into a continuous band. Here, we investigate the effects of both qubit and photon dissipation on the phase transition and on the instability induced by the spectral collapse. Using a mean-field decoupling approximation, we analytically obtain the steady-state expectation values of the observables signaling a symmetry breaking, identifying a first-order phase transition from the normal to the superradiant phase. Our stability analysis unveils a very rich phase diagram, which features stable, bistable, and unstable phases depending on the dissipation rate.
We establish a new theoretical framework, based on a time-dependent mean field approach, to address the dynamics of the driven Dicke model, describing, e.g., an atomic sample of N teo-level systems coupled to a cavity field, and driven by an external pump. We provide a description of the dynamics that also includes the effects of quantum fluctuations. The joint evolution of both mean fields and quantum fluctuations gives rise to a rich and generally non-linear dynamics, featuring a normal and a super radiant regime, which are the dynamical counterpart of the two static quantum phases. Various dynamical phenomena emerge, such as the spontaneous amplification of vacuum fluctuations, or the appearance of three stable points around which the mean field amplitudes rotate during time evolution. We also provide a characterization of the driving induced photon production by analyzing the average photon number, the Mandel parameter, the work done by the driving agent, and the non-adiabaticity of the process, evaluated in terms of the inner friction. Finally, we discuss the squeezing and the entanglement between the atomic system and the cavity mode.
We study the complex nonlinear dynamics of the two-photon Dicke model in the semiclassical limit by considering cavity and qubit dissipation. In addition to the normal and super-radiant phases, another phase that contains abundant chaos-related phenomena is found under balanced rotating and counter-rotating couplings. In particular, chaos may manifest itself through period-doubling bifurcation, intermittent chaos, or quasi-periodic oscillation, depending on the value of qubit frequency. Transition mechanisms that exist in these three distinct routes are investigated through the system's long-time evolution and bifurcation diagram. Additionally, we provide a comprehensive phase diagram detailing both the existence of stable fixed points and the aforementioned chaos-related dynamics.