Exponential attractor for Hindmarsh-Rose equations in neurodynamics

The existence of exponential attractor for the diffusive Hindmarsh-Rose equations on a three-dimensional bounded domain in the study of neurodynamics is proved through uniform estimates and a new theorem on the squeezing property of the abstract reaction-diffusion equation established in this paper. This result on the exponential attractor infers that the global attractor whose existence has been proved in [22] for the diffusive Hindmarsh-Rose semiflow has a finite fractal dimension.     

A short walk through quantum optomechanics

This paper gives a brief review of the basic physics of quantum optomechanics and provides an overview of some of its recent developments and current areas of focus. It first outlines the basic theory of cavity optomechanical cooling and gives a brief status report of the experimental state‐of‐the‐art. It then turns to the deep quantum regime of operation of optomechanical oscillators and covers selected aspects of quantum state preparation, control and characterization, including mechanical squeezing and pulsed optomechanics. This is followed by a discussion of the “bottom‐up” approach that exploits ultracold atomic samples instead of nanoscale systems. It concludes with an outlook that concentrates largely on the functionalization of quantum optomechanical systems and their promise in metrology applications.     

Revisiting non-degenerate parametric down-conversion

The quantum dynamics of a two-mode non-resonant parametric down-conversion process is studied by recasting the time evolution equations for the basic operators in an equivalent spin equation form with simpler exact solutions for a pump field with harmonic time dependence. Expectation values of suitable operators for studying important features such as squeezing and quantum revivals are presented in simple forms.      

W态纠缠实现双腔远程控制原子的非经典特性

考虑将双模纠缠相干光场的两模场同时分别注入两个腔中,初态处于W态的三体纠缠二能级原子中的两个分别在这两个腔内,并且都与光场发生共振相互作用,经腔QED演化之后,对纠缠相干光场进行光子探测和对纠缠原子进行选择性测量,通过操纵相互作用的时间和光场的参数可控制W态中处于腔外的第三个原子的非经典效应,如粒子数布居差的崩塌一回复现象和偶极压缩现象,从而实现了更强地远程控制原子的非经典特性.     

与二项式光场相互作用的运动原子熵压缩

运用量子信息熵理论,研究了二项式光场与运动二能级原子相互作用过程中运动原子的信息熵压缩。讨论了不同的原子初态和场的有关参数对原子信息熵压缩的影响。结果表明：选择原子初态、场模结构、场调节参数及原子运动速度可以调控原子信息熵的压缩方向、偶极矩分量值和压缩周期;适当的选择参数可得到持续性的原子信息熵压缩。     

变频率光场与二能级原子的相互作用：双光子过程

研究了二能级原子与单模电磁场相互作用时的双光子过程,主要考虑了在相干态初始条件下场频率发生变化时的情况,讨论了场频率随时间作正弦缓慢变化对原子布居数反转、光场压缩与原子压缩等特性的影响.结果显示,场频率的改变将使得原子布居数反转的崩塌回复周期增大,回复值减小,而光场及原子压缩效应减弱. 关键词： 布居数反转 光场压缩 原子压缩 双光子过程     

Strong Squeezing of Duffing Oscillator in a Highly Dissipative Optomechanical Cavity System

In the conventional scheme of generating strong mechanical squeezing by the joint effect between mechanical parametric amplification and sideband cooling, the resolved sideband condition is required so as to overcome the quantum backaction heating. In the unresolved sideband regime, to suppress the quantum backaction, a χ⁽²⁾ nonlinear medium is introduced to the cavity. The result shows that the quantum backaction heating effect caused by unwanted counter-rotating term can be completely removed. Hence, the strong mechanical squeezing can be obtained even for the system far from the resolved-sideband regime.     

有限维希尔伯特空间奇偶相干态压缩特性的数值研究

运用数值计算方法研究了有限维希尔伯特空间谐振子奇偶相干态的压缩特性.研究表明,有限维空间奇偶相干态展现了与通常奇偶相干态截然不同的压缩性质,奇相干态不存在二阶压缩但存在振幅平方压缩;偶相干态不仅存在压缩而且存在振幅平方压缩.通常的奇偶相干态是上述奇偶相干态的特例.     

The Effect of Incoherent Population Pumping on Squeezing in Resonance Fluorescence

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Squeezing Properties of Three-Level Atomic Collective Dipole Phase Quadrature Operators with Respect to Three-Level Atomic Coherent State

We add some useful formulations except for Ref. [4], then investigate the squeezing properties of the atomic collective dipole phase quadrature operators with respect to three-level atomic coherent state in detail. We mainly discuss two extreme cases concerning parameter α and β and obtain some interesting conclusions.