Single-atom entropy squeezing and quantum entanglement in Tavis--Cummings model with atomic motion

We examine the single-atom entropy squeezing and the atom-field entanglement in a system of two moving twolevel atoms interacting with a single-mode coherent field in a lossless resonant cavity.Our numerical calculations indicate that the squeezing period,the squeezing time and the maximal squeezing can be controlled by appropriately choosing the atomic motion and the field-mode structure.The atomic motion leads to a periodical time evolution of entanglement between the two-atom and the field.Moreover,there exists corresponding relation between the time evolution properties of the atomic entropy squeezing and that of the entanglement between the two atoms and the field.     

有限维希尔伯特空间非简谐振子广义相干态

在有限维希尔伯特空间中构造了非简谐振子的广义相干态,并研究了其量子统计特性。详细地讨论了该量子态的压缩效应和反聚束效应,得到了出现压缩的条件并给陋了反聚束效应与有限维希尔伯特空间维数关系的数值计算结果。理论计算表明该量子态存在压缩效应和反聚束效应,这与通常的无限维空间中的广义相干态是完全不同的。     

Coherence and squeezing in superpositions of spin coherent states

We consider the superpositions of spin coherent states and study the coherence properties and spin squeezing in these states. The spin squeezing is examined using a new version of spectroscopic squeezing criteria. The results show that the antibuching effect can be enhanced and spin squeezing can be generated in the superpositions of two spin coherent states.     

叠加激发双模压缩真空态的量子统计特性(英文)

从激发双模压缩真空态a^+mb^+m|ξ>出发构造了叠加态|Ψ>,研究了|Ψ>的量子统计特性.结果表明:在一定的条件下,随着相位差的变化,叠加态|Ψ>的平均光子数出现类似于Rabi振荡的崩塌与复原现象,而且与单个激发双模压缩真空态a^+mb^+m|ξ>相比,在叠加态|Ψ>中光场的相位压缩和亚泊松光子统计特性都得到了加强.     

两不同奇相干态组成的第种四态叠加多模叠加态光场的等阶N次方Y压缩

本文构造了由两不同奇相干态组成的第Ⅲ种四态叠加多模叠加态光场|Ψ_o⁽⁴⁾,Ⅲ>_q.利用新近建立的多模压缩态理论,详细研究了态|Ψ_o⁽⁴⁾,Ⅲ>_q的广义非线性等阶N次方Y压缩特性,结果发现由不呈现等阶高阶压缩效应的两奇相干态线性叠加组成的新量子光场态|Ψ_o⁽⁴⁾,Ⅲ>_q呈现出许多奇异物理现象:1)当压缩阶数N=4m(m=1,2,3,…,…)时,态|Ψ_o⁽⁴⁾,Ⅲ>_q始终恒处于等阶N-Y最小测不准态;2)当压缩阶数N=4m-2(m=1,2,3,…,…)时,在一定条件下,态|Ψ_o⁽⁴⁾,Ⅲ>_q的某一正交分量处于等阶N-Y最小测不准态时,另一正交分量则始终既不处于等阶N-Y最小测不准态,也不呈现等阶N次方Y压缩效应,这种现象称为“半相干态”效应;在另外一些条件下,态|Ψ_o⁽⁴⁾,Ⅲ>_q的两正交分量可分别呈现出等阶N次方Y压缩效应,其压缩特性具有周期性变化的、互补对称的关系.3)当压缩阶数N为奇数时,态|Ψ_o⁽⁴⁾,Ⅲ>_q始终不会呈现等阶N次方Y压缩效应,也不处于等阶N-Y最小测不准态,但在一定条件下可呈现“半相干态”效应.     

两偶极相互作用原子系统中的偶极平方压缩

研究了两个存在偶极相互作用的原子系统中的偶极平方压缩效应,讨论了原子偶极相互作用以及相位信息对压缩效应的影响,并进而探讨了原子偶极平方压缩与光场振幅平方压缩之间的关联.     

SQUEEZING PROPERTIES OF A TRAPPED ION IN THE STANDING-WAVE LASER

We investigate the squeezing properties of a trapped ion in a standing-wave laser. Our results show that the squeezing of a trapped ion in the standing-wave laser is dependent on its position in the latter, the detuning parameter and the initial average phonon number.     

Optimal entropy squeezing sudden generation and its control for an effective two-level moving atom entanglement with the two-mode coherent fields

From the viewpoint of quantum information, this paper proposes a concept and a definition of the atomic optimal entropy squeezing sudden generation (AOESSG) for the system of an effective two-level moving atom which entangles with the two-mode coherent fields. It also researches the relationship between the AOESSG and entanglement sudden death of the atom-fields, and discusses the influences of atomic initial state on the AOESSG and obtains the system parameter which controls the AOESSG.     

Energy Shift Caused by Non-isotropy of 2-Dimensional Anisotropic Quantum Dot in Presence of Uniform Magnetic Field

Based on the squeezing mechanism in quantum dots in the presence of uniform magnetic field, we derive the energy shift caused by the non-isotropy of 2-dimensional anisotropic quantum dot. We also study sudden squeezing of the size of the quantum dot. The whole discussion is proceeded smoothly by virtue of the entangled state representation.     

带有阻尼项的广义对称正则长波方程的指数吸引子

考虑了带有阻尼项的广义对称正则长波方程的整体快变动力学．证明了与该方程有关的非线性半群的挤压性质和指数吸引子的存在性．对指数吸引子的分形维数的上界也进行了估计．