振幅相干态的量子统计性质

对振幅相干态|ψ＞的非经典性质进行了研究，用数值计算的方法讨论了它的振幅压缩性质、亚泊松分布特性和反聚束效应。     

增加光子位移福克态的量子统计性质

引入了增加光子位移福克态 a^+m| α,n〉,其中 | α,n〉是位移福克态,m是整数.用数值计算的方法研究了这种态的量子统计性质.结果表明,在位移福克态上增加光子后可以使原有的光场呈现较强的压缩,并能使光场的亚泊松特性得到明显增强.     

Kerr 介质中三能级原子与双模场非共振相互作用的量子统计性质

研究了Kerr介质中双模场与V型三能级原子的非共振相互作用. 对Cauchy-Schwartz不等式的研究表明,在两模场失谐量相等(δ₁=δ₂)条件下,当初始场强ξ一定而两模场的光子数差q减小时,场的非经典相关程度加强;q一定而ξ增大时,场的非经典相关程度减弱. 当Δδ=|δ₂-δ₁|≠0且q和ξ的取值一定时,随介质常量x的增大,光场两模间的非经典相关程度减弱,且Δδ的大小对这种非经典相关程度的减弱有重要影响. 对场的 关键词： Kerr介质 非共振相互作用 Cauchy-Schwartz不等式 场的二阶关联函数     

二项-负二项组合光场态的光子统计性质及其在量子扩散通道中的生成

在组合二项-负二项分布的基础上, 提出了二项-负二项组合光场态, 这种态能在Fock态历经量子扩散通道的过程中实现. 导出了此光场的二阶相干度公式, g⁽²⁾(t) =2-((m²+m)/(m+κt²)), 发现随着时间的推移光场从非经典Fock态变为经典态, 光子数m 经扩散通道后变成了 m+κt, κ是扩散常数, 相应的光子统计从亚泊松分布历经泊松分布再变成混沌光; 初始Fock态的光子数越多, 则扩散所需的时间越长.     

利用分束器通过条件测量制备非经典光场态和量子纠缠态

把相干态和单粒子数态作为分束器的输入态，通过条件测量可以剪去输入相干态中的任意粒子数态，并研究了这些被剪切了的光场态的性质。结果显示剪去真空态和单粒子数态的输出态具有较强的压缩和亚泊松分布等非经典效应。把剪切了的输出态和真空态输入分束器，得到的输出态具有量子纠缠性质，从而制备出量子纠缠态，同时也验证了被剪切的输出态的非经典性。     

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.     

类科尔介质中受激辐射场的量子统计性质

本文讨论类科尔介质腔中场模与三能级原子相互作用时辐射场的量子统计性质。结果表明,介质与场模的相互作用使场模与原子的相互作用减弱,光子一般不表现反聚束性质,辐射场服从超亚泊松统计分布。     

受驱动的关联发射激光:双模亚泊松光

如果在关联发射的基础之上再引入原子相干，这样的系统可产生明亮的双模亚泊松光。运用Ｓｃｕｌｙ－Ｌａｍｂ理论计算ＭａｎｄｅｌＱ因子，一方面，当相对相位和相对振幅的量子噪声被抑制到真空噪声水平时，平均模呈现亚泊松光子分布；或者当平均相位和平均振幅的量子噪声被抑制到真空噪声水平时，相对模呈现亚泊松光子分布，ＭａｎｄｅｌＱ因子的最佳值均可达到－０．５。在上述两种情况下，每个关联发射激光（ＣＥＬ）模呈现亚泊松光子分布，ＭａｎｄｅｌＱ因子的最佳值均可达到－０．２５。     

类Kerr介质中双模SU(1,1)相干态场与Λ型三能级原子相互作用的量子统计性质

导出了类Kerr介质中双模SU(1,1)相干态场与Λ型三能级原子相互作用系统的态函数,研究了Kerr效应对Λ型三能级原子布居概率、双模SU(1,1)相干态场的互关联函数、Cauchy-Schwartz不等式及二阶相干度的影响.结果表明:Kerr效应使原子与光场的耦合减弱,原子布居的崩塌与复苏的周期缩短;在初始光场较弱和较强两种情况下,类Kerr介质对双模SU(1,1)相干态场两模间的相关性、相关程度以及光子的聚束与反聚束效应产生的作用有明显的区别.     

量子拍激光：双模亚泊松光

在Λ型量子拍系统中再引入原子相干，可以产生明亮的双模亚泊松光.运用Scully-Lamb理论计算了MandelQ因子.当相对相位和相对振幅的量子噪声被抑制到真空噪声水平时，平均模呈现亚泊松光子分布；或者当平均相位和平均振幅的量子噪声被抑制到真空噪声水平时，相对模呈现亚泊松光子分布，MandelQ因子的最佳值均可达到-0.5；并且，在上述两种情况下，每个关联自发辐射激光模呈现亚泊松光子分布，MandelQ因子的最佳值均可达到-0.25. 关键词：     

Quantum Statistical Behaviors of Interaction of an Atomic Bose-Einstein Condensate with Laser

We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose-Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-number distribution, while the atomic field is initially in a Fock state, it is found that there is energy exchange between photons and atoms. For the input and output states, the photons and atoms may exhibit the sub-Poissonian distribution. The input and output laser fields may exhibit quadrature squeezing, but for the atomic field, only the output state exhibits quadrature squeezing. It is shown that there exists the violation of the Cauchy-Schwartz inequality, which means that the correlation between photons and atoms is nonclassical.     

Quantum Correlation of Many Atoms in Spinor Bose-Einstein Condensates

In this letter, we have studied sub-Poissonian distributions and quantum correlation of atoms in spinor Bose-Einstein condensates. It is found that there exists the sub-Poissonian distributions for spin-1 and spin-(-1) components, respectively. There may exist the violation of the Cauchy-Schwartz inequality. For the same atomic numbers, the regions that include violation of the Cauchy-Schwartz inequality will shift rightwards with the increment of the Rabi frequency, whereas for the same Rabi frequency, the regions will shift leftwards with the increment of the atomic numbers.     

Properties of the States Generated by the Excitations on a q-Coherent State

We study the mathematical and physical properties of the states which are generated by excitation on a q-analogue of the coherent state. With the help of a q-analogue of the Laguerre polynomial, the squeezing and the statistical properties of the field in such the state are also discussed.     

Quantum Statistical Behaviors of Interaction of an Atomic Bose-Einstein Condensate with Laser

We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-number distribution, while the atomic field is initially in a Fock state, it is found that there is energy exchange between photons and atoms. For the input and output states, the photons and atoms may exhibit the sub-Poissonian distribution. The input and output laser fields may exhibit quadrature squeezing, but for the atomic field, only the output state exhibits quadrature squeezing. It is shown that there exists the violation of the Cauchy-Schwartz inequality, which means that the correlation between photons and atoms is nonclassical.``     

Quantum Statistical Properties of the Exciton in a Leaky Quasi-Mode Cavity

We have studied quantum statistical properties of the exciton in a leaky quasi-mode cavity. It is shown that when the exciton is initially in a squeezed coherent state whereas cavity initially in a vacuum state, there is energy exchange between the exciton and cavity. Both the exciton and cavity may exhibit sub-Poissonian distribution and exist quadrature squeezing. Calculation shows that correlation between the exciton and cavity is classical, which implies that there is not the violation of the Cauchy-Schwartz inequality.     

Quantum Statistical Properties of the Exciton in a Leaky Quasi-Mode Cavity

We have studied quantum statistical properties of the exciton in a leaky quasi-mode cavity. It is shown that when the exciton is initially in a squeezed coherent state whereas cavity initially in a vacuum state, there is energy exchange between the exciton and cavity. Both the exciton and cavity may exhibit sub-Poissonian distribution and exist quadrature squeezing. Calculation shows that correlation between the exciton and cavity is classical, which implies that there is not the violation of the Cauchy-Schwartz inequality.     

Quantum Statistical Properties of k-Quantum Nonlinear Coherent States

In our preceding work, a class of k-quantum nonlinear coherent states, i.e., the k eigenstates of the powersBk (k ≥ 3) of the annihilation operator B=-a1/f(N) of f-oscillators, are introduced. In this paper, we introduce a newkind of higher-order squeezing and an antibunching effect. The quantum statistical properties of the k states are studied.The result shows that the M-th order [M = (n 1/2)k; n = 0, 1,...] squeezing effects exist in all of the k states when kis even. There is the antibunching effect in all of the k states.     

Quantum Statistical Properties of k-Quantum Nonlinear Coherent States

In our preceding work, a class of k-quantum nonlinear coherent states, i.e., the k eigenstates of the powers B^^k (k≥3) of the annihilation operator B^ =a^ 1/f(N^) of f-oscillators, are introduced. In this paper, we introduce a new kind of higher-order squeezing and an antibunching effect. The quantum statistical properties of the k states are studied. The result shows that the M-th order [M=(n 1/2)k; n=0, 1,...] squeezing effects exist in all of the k states when k is even. There is the antibunching effect in all of the k states.     

Quantum Statistical Properties in Two—Species Bose—Einstein Condensates

We have studied quantum statistical properties in a zero-temperature two-species Bose-Einstein condensate system in the presence of the nonlinear self-interaction of each species,the interspecies nonlinear interaction,and the Jisephson-like tunneling interaction.It is found that the two condensates may periodically exhibit sub-Poissonian distribution.It is revealed that the correlation between the two condensates can be nonclassical,which means that there exists a violation of Cauchy-Schwartz inequality.The nonclassical effect about the correlation between the two condensates can be realized experimentally by properly preparing the total number of atoms in the two condensates.     

New Even and Odd Nonlinear Coherent States and Their Nonclassical Properties

In this paper, a new kind of even and odd nonlinear coherent states (NLCSs) are introduced. Some nonclassical properties of the states are investigated. It has been found that the new even and odd NLCSs exhibit quadrature squeezing and amplitude-squared squeezing in the Y ₂ direction, however the new odd NLCSs only display sub-Poissonian behaviour. The results show that the nonclassical properties of the new even and odd NLCSs are rather different from those of the usual even and odd coherent states and NLCSs. PACS numbers:42.50.-p, 03.65.-w