单模腔中两个二能级原子纠缠引起的原子质心微幅低频经典谐振

Prediction and retrodiction for a continuously monitored superconducting qubit

The quantum state of a superconducting transmon qubit inside a three-dimensional cavity is monitored by reflection of a microwave field on the cavity. The information inferred from the measurement record is incorporated in a density matrix $ρ_t$, which is conditioned on probe results until $t$, and in an auxiliary matrix $E_t$, which is conditioned on probe results obtained after $t$. Here, we obtain these matrices from experimental data and we illustrate their application to predict and retrodict the outcome of weak and strong qubit measurements.

表面光学力学：计算微球中的光激发声学回音壁模式

Surface optomechanics: Calculating optically excited acoustical whispering gallery modes in microspheres

受激布里渊散射最近允许在微型器件中实验激发表面声共振，从而能够以50 MHz至12 GHz的速率振动。这种机械回音壁模式在光子MEMS中的实验可用性提出了关于其结构和光谱分布的问题。在这里，我们计算这种振动表面回音壁模式的形式和频率，揭示不同类型的表面振动，包括纵向，横向和瑞利型变形。我们参数调查这些不同的模式，通过改变它们的顺序在方位角，径向和极方向，以揭示不同的振动结构，包括机械共振，本地化的界面附近的环境，在那里他们可以感觉到周围环境的变化。

Optomechanical many-body cooling using frustration

We show that the vibrations of an ion Coulomb crystal can be cooled to the zero-point motion through the optomechanical coupling with a high-finesse cavity. Cooling results from the interplay between coherent scattering of cavity photons by the ions, which dynamically modifies the vibrational spectrum, and cavity losses, that dissipate motional energy. The cooling mechanism we propose requires that the length scales of the crystal and the cavity are mismatched so that the system is intrinsically frustrated, leading to the formation of defects (kinks). When the pump is strong enough, the anti-S…

Quantum theory of collective strong coupling of molecular vibrations with a microcavity mode

We develop a quantum mechanical formalism to treat the strong coupling between an electromagnetic mode and a vibrational excitation of an ensemble of organic molecules. By employing a Bloch-Redfield-Wangsness approach, we show that the influence of dephasing-type interactions, i.e., elastic collisions with a background bath of phonons, critically depends on the nature of the bath modes. In particular, for long-range phonons corresponding to a common bath, the dynamics of the "bright state" (the collective superposition of molecular vibrations coupling to the cavity mode) is effectively decoupl…

从经典随机动力学到监控量子动力学：东电路模型中的动力学相共存

From Classical Stochastic to Monitored Quantum Dynamics: Dynamical Phase Coexistence in East Circuit Models

研究监控量子电路模型在经典随机与单位元量子动力学之间的动力学相共存现象，通过测量记录探索量子 regime 中的动力学相共存持续性。

Coherent coupling of molecular resonators with a micro-cavity mode

The optical hybridization of the electronic states in strongly coupled molecule-cavity systems have revealed unique properties such as lasing, room temperature polariton condensation, and the modification of excited electronic landscapes involved in molecular isomerization. Here we show that molecular vibrational modes of the electronic ground state can also be coherently coupled with a micro-cavity mode at room temperature, given the low vibrational thermal occupation factors associated with molecular vibrations, and the collective coupling of a large ensemble of molecules immersed within the…

Entangling mechanical vibrations of two massive ferrimagnets by fully exploiting the nonlinearity of magnetostriction

Quantum entanglement in the motion of macroscopic objects is of significance to both fundamental studies and quantum technologies. Here we show how to entangle the mechanical vibration modes of two massive ferrimagnets that are placed in the same microwave cavity. Each ferrimagnet supports a magnon mode and a low-frequency vibration mode coupled by the magnetostrictive force. The two magnon modes are, respectively, coupled to the microwave cavity by the magnetic dipole interaction. We first generate a stationary nonlocal entangled state between the vibration mode of the ferrimagnet-1 and the m…