Atom-field correlations in the weak-excitation limit of absorptive optical bistability

Spatial correlations of one dimensional driven-dissipative systems of Rydberg atoms

We consider a one-dimensional lattice of atoms with laser excitation to a Rydberg state and spontaneous emission. The atoms are coupled due to the dipole-dipole interaction of the Rydberg states. This driven-dissipative system has a broad range of non-equilibrium phases, such as antiferromagnetic ordering and bistability. Using the quantum trajectory method, we calculate the spatial correlation function throughout the parameter space for up to 20 lattice sites. We show that bistability significantly strengthens the spatial correlations and entanglement.

Bistable optical transmission through arrays of atoms in free space

We determine the transmission of light through a planar atomic array beyond the limit of low light intensity that displays optical bistability in the mean-field regime. We develop a theory describing the intrinsic optical bistability, which is supported purely by resonant dipole-dipole interactions in free space, showing how bistable light amplitudes exhibit both strong cooperative and weak single-atom responses and how they depend on the underlying low light intensity collective excitation eigenmodes. Similarities of the theory with optical bistability in cavities are highlighted, while recur…

Nonreciprocity light propagation in coupled microcavities system beyond weak-excitation approximation

We propose an alternative scheme for nonreciprocal light propagation in two coupled cavities system, in which a two-level quantum emitter is coupled to one of the optical microcavities. For the case of parity-time (\textrm{PT}) system (i.e., active-passive coupled cavities system), the cavity gain can significantly enhance the optical nonlinearity induced by the interaction between a quantum emitter and cavity field beyond weak-excitation approximation. The giant optical nonlinearity results in the non-lossy nonreciprocal light propagation with high isolation ratio in proper parameters range. …

Spontaneous generation, enhanced propagation and optical imprinting of quantized vortices and dark solitons in a polariton superfluid: towards the control of quantum turbulence

In resonantly pumped polariton superfluids we recently explored a new regime based on the bistability of the polariton system to enhance the propagation of polariton fluids up to macroscopic distances. This technique together with an all-optical imprinting method allowed the generation and control of various topological excitations such as quantized vortices and dark solitons. The flexibility and scalability of the new experimental scheme opens the way to the systematic study of quantum turbulence in driven dissipative quantum fluids of light. In this article we review the basic working princi…

光子在透射前作为原子激发存在多长时间？

How much time does a photon spend as an atomic excitation before being transmitted?

本文利用弱值形式体系研究单光子穿过二能级原子云时作为原子激发存在的时间，证明透射光子的该时间等于可正可负的群延迟，散射光子的该时间等于群延迟与Wigner时间延迟之和，从而修正了以往关于透射光子激发时间为零的直觉。

Cavity optomechanics with synthetic Landau levels of ultra cold Fermi gas

Ultra cold fermionic atoms placed in a synthetic magnetic field arrange themselves in Landau levels. We theoretically study the optomechanical interaction between the light field and collective excitations of such fermionic atoms in synthetic magnetic field by placing them in side a Fabry Perot cavity. We derive the effective hamiltonian for particle hole excitations from a filled Landau level using a bosonization technique and obtain an expression for the cavity transmission spectrum. Using this we show that the cavity transmission spectrum demonstrates cold atom analogue of Subnikov de Hass …

玻色凝聚与布里托夫激发在嵌入谐振腔的超导量子比特网络中

Bose condensation and Bogoliubov excitation in resonator-embedded superconducting qubit network

该研究通过双音频谱学实验，在超导量子比特网络中观察到玻色凝聚与布里托夫激发的双稳态特性。

Critical dynamical properties of a first-order dissipative phase transition

We theoretically investigate the critical properties of a single driven-dissipative nonlinear photon mode. In a well-defined thermodynamical limit of large excitation numbers, the exact quantum solution describes a first-order phase transition in the regime where semiclassical theory predicts optical bistability. We study the behavior of the complex spectral gap associated with the Liouvillian superoperator of the corresponding master equation. We show that in this limit the Liouvillian gap vanishes exponentially and that the bimodality of the photon Wigner function disappears. The connection …

热里德伯原子气体中平均场相互作用的时间延迟

Time delay of mean field interaction in thermal Rydberg atomic gas

本文通过实验发现热里德伯原子气体中平均场相互作用的建立存在时间延迟，提出碰撞电离的微观机制，定量解释光学双稳态滞回窗口，并有助于理解自持振荡现象。

玻色-爱因斯坦凝聚体在横向泵浦红移腔中的相图和动态相

Phase Diagram and dynamical phases of self organization of a Bose-Einstein condensate in a transversely pumped red-detuned cavity

研究了玻色-爱因斯坦凝聚体在横向泵浦红移腔中的相图和动态相，揭示了自组织现象中的稳定性、混沌轨迹和时空模式形成机制。