Superradiant optomechanical phases of cold atomic gases in optical resonators
Superradiant optomechanical phases of cold atomic gases in optical resonators
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光学谐振腔中冷原子气体的超辐射光机械相
DOI：
10.1103/physreva.101.023616
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发表时间：
2019
影响因子：
2.9
通讯作者：
G. Morigi
中科院分区：
文献类型：
--
作者：
Simon B. Jäger;M. Holland;G. Morigi
当考虑光子-原子相互作用的机械效应时，我们从理论上分析了冷原子气体的超辐射发射。原子被限制在驻波谐振器内，原子亚稳态偶极跃迁耦合到腔模式。原子偶极子在参数范围内被非相干泵浦，该参数范围对应于在不存在不均匀展宽的情况下的稳态超辐射度。从腔场和原子自由度的主方程出发，我们推导了一个平均场模型，该模型使我们能够确定阈值温度，高于该温度的热波动会抑制超辐射发射。然后，我们分析了用平均场模型描述运动时超辐射发射的动力学。在半经典状态和低于阈值温度下，我们观察到发射的光可以是相干的或混乱的，具体取决于非相干泵浦速率。然后，当超辐射衰减率 $\Lambda$ 与反冲频率 $\omega_R$ 数量级时，我们分析零温下理想玻色气体的超辐射发射。我们表明，原子和场之间机械能的量子化交换会产生一个阈值$\Lambda_c$，低于该阈值超辐射发射会衰减为零。当 $\Lambda>\Lambda_c$ 超辐射发射伴随着物质波光栅的形成，衍射发射的光子。这些光栅的稳定性取决于相对于第二阈值$w_c$的非相干泵浦速率$w$。对于 $w>w_c$，光栅是稳定的并且系统实现了稳态超辐射。低于第二个阈值，耦合动力学变得混乱。我们描述了这两个阈值的动态特征，并表明我们预测的三个阶段（不相干、相干、混沌）可以通过腔输出处光的相干特性来揭示。
We theoretically analyze superradiant emission of light from a cold atomic gas, when mechanical effects of photon-atom interactions are considered. The atoms are confined within a standing-wave resonator and an atomic metastable dipolar transition couples to a cavity mode. The atomic dipole is incoherently pumped in the parameter regime that would correspond to stationary superradiance in absence of inhomogeneous broadening. Starting from the master equation for cavity field and atomic degrees of freedom we derive a mean-field model that allows us to determine a threshold temperature, above which thermal fluctuations suppress superradiant emission. We then analyze the dynamics of superradiant emission when the motion is described by a mean-field model. In the semiclassical regime and below the threshold temperature we observe that the emitted light can be either coherent or chaotic, depending on the incoherent pump rate. We then analyze superradiant emission from an ideal Bose gas at zero temperature when the superradiant decay rate $\Lambda$ is of the order of the recoil frequency $\omega_R$. We show that the quantized exchange of mechanical energy between the atoms and the field gives rise to a threshold, $\Lambda_c$, below which superradiant emission is damped down to zero. When $\Lambda>\Lambda_c$ superradiant emission is accompanied by the formation of matter-wave gratings diffracting the emitted photons. The stability of these gratings depends on the incoherent pump rate $w$ with respect to a second threshold value $w_c$. For $w>w_c$ the gratings are stable and the system achieves stationary superradiance. Below this second threshold the coupled dynamics becomes chaotic. We characterize the dynamics across these two thresholds and show that the three phases we predict (incoherent, coherent, chaotic) can be revealed via the coherence properties of the light at the cavity output.
平均场和量子多体动力学中的分层混沌
影响因子：
2.9
作者：
Valdez, Marc Andrew;Shchedrin, Gavriil;Sols, Fernando;Carr, Lincoln D.
通讯作者：
Carr, Lincoln D.