- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Dynamical Properties of the Finite-size Dicke Model Coupled to a Thermal Reservoir
摘要： We investigate the dynamical properties of the finite-size Dicke model coupled to a photon reservoir in the dispersive regime. The system–reservoir coupling in our Hamiltonian includes counter-rotating terms, which are relevant in the strong atom–cavity coupling. Because the dispersive regime is considered, the dynamics of low-energy states are described sufficiently accurately within the finite-dimensional subspace of the dressed states. Using the separation of the time scales between the system and the reservoir, we derive the Markovian quantum master equation in the subspace without ignoring the counter-rotating terms. The temporal evolution of the expectation of the cavity mode shows that the bifurcation of the long-lived state corresponds to the superradiant transition in the isolated model. The master equation explicitly gives the steady state solution. The numerical results for the first-order correlation function on the steady state indicate that the strong atom–cavity coupling enhances the coherence and softens the dephasing in the superradiant region.
关键词： dephasing,coherence,quantum master equation,superradiant transition,Dicke model
更新于2025-09-16 10:30:52
-
Weak superradiance in arrays of plasmonic nanoantennas
摘要： A collection of N emitters can exhibit an N-fold broadening of the radiative linewidth resulting from the development of a macroscopic dipole moment. Such a broadening of the radiative linewidth has previously been observed in systems of several nanoparticles and has often been described in terms of superradiant behavior. However, the understanding of the physics behind the observed dependence of radiative linewidth on the number of irradiated nanoparticles is far from complete. In this paper, we present theoretical and experimental results that elucidate this broadening mechanism in plasmonic systems and draw a connection with the phenomenon of Dicke superradiance. We demonstrate that, in the limit where radiative broadening dominates, the extinction linewidth of a planar array of plasmonic nanoantennas scales linearly with the number of nanoantennas contained within a circle of radius equal to the resonant optical wavelength. We explain this classical phenomenon as a weak superradiance effect, which corresponds to the case in the Dicke model where only the ground state and the first collective excited state contribute to the enhanced radiation.
关键词： superradiance,radiative linewidth,Dicke model,plasmonic nanoantennas,collective behavior
更新于2025-09-16 10:30:52
-
Superlattice switching from parametric instabilities in a driven-dissipative Bose-Einstein condensate in a cavity
摘要： We numerically obtain the full time-evolution of a parametrically driven-dissipative Bose-Einstein condensate in an optical cavity and investigate the implications of driving for the phase diagram. Beyond the normal and superradiant phases, a third nonequilibrium phase emerges as a many-body parametric resonance. This dynamical phase switches between two symmetry-broken superradiant configurations. The switching is accompanied by a substantial occupation of other momentum states not retained in the mapping to the Dicke model. The emergent phase shows features of nonintegrability and thermalization.
关键词： optical cavity,parametric resonance,Dicke model,thermalization,Bose-Einstein condensate
更新于2025-09-10 09:29:36
-
Cavity-QED interactions of several atoms
摘要： We study many-atom van der Waals forces arising from reversible atom–field interactions in cavity quantum electrodynamics by using a dressed-state approximation. In the most general case, a single-mode Dicke model for atoms, sharing an arbitrary number of excitations, placed in an imperfect cavity has been developed that leads to the vdW potential of such system. As special cases, we consider the single-excitation Dicke model and also the case of one atom in the presence of multi-photon excitation inside the cavity. In most of the paper, it is assumed that the atoms are distributed symmetrically with respect to the mode structure. This will decouple all asymmetric states, allowing us to ignore them throughout our calculations. The impact of asymmetric states is taken into account for a system wherein one atom, freely placed in a cavity, together with n ? 1 equally-coupled atoms is interacting with the cavity field. By assuming broadened Lorentzian modes instead of sharp ones, the cavity imperfections have been added to the calculations. The position dependence of the effective Rabi frequency is studied for the example of a planar cavity.
关键词： cavity quantum electrodynamics,van der Waals forces,planar cavity,dressed-state approximation,Dicke model,Rabi frequency
更新于2025-09-04 15:30:14