共查询到20条相似文献,搜索用时 15 毫秒
1.
The time evolution of spontaneous decay of a two-level atom in one dimension photonic crystals is investigated with three different methods : ( 1 ) using the Markovian approximation, (2) using the constant approximation, and (3) without using any of the two approximations. The second and third methods are Non-Markovian, which yield similar results. The second method gives us a clear physical picture of the effect of the reflected field. The Non- Markovian processes due to the reflected field have great influence on the atomic decay mainly within one tenth of an optical cycle, and reach steady state influence fter one optical cycle. The result of Markovian approximation gives almost the same result of the other two methods after one optical cycle, but misses the details within the one optical cycle. 相似文献
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YANGXiao-Xue WUYing 《理论物理通讯》2003,40(5):585-588
We present analytical results for the multiphoton squeezed states defined through nonlinear quadrature-dependent Bogoliubov transformations. These analytical results turn a nonlinear problem into an essentially linear one and they can be utilized to express explicitly the mean walues and deviations of the quadrature operators and the photon variables under the multiphoton states in terms of those quantities averaged over the standard squeezed states which only involves the quadrature-independent Bogoliubov transformation. 相似文献
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We present analytical results for the multiphoton squeezed states defined through nonlinear quadraturedependent Bogoliubov transformations. These analytical results turn a nonlinear problem into an essentially linear one and they can be utilized to express explicitly the mean values and deviations of the quadrature operators and the photon variables under the multiphoton states in terms of those quantities averaged over the standard squeezed states which only involves the quadrature-independent Bogoliubov transformation. 相似文献
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文中研究了广义含时谐振子系统的不变量和不变量的一般形式,并利用基本不变量构造了此含时系统的压缩态和压缩激态。 相似文献
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We propose and study a new kind of superposition states: even-and odd-displaced squeezed states, defined as [D(z)+D(-z)]S(γ)|0> and [D(z)-D(-z)]S(γ)|0>, which are characteristic of possessing even and odd photon numbers respectively. We find that the even-displaced squeezed state may exhibit stronger squeezing than that of the ordinary squeezed state D(z)S(γ)|0>. 相似文献
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P. K. Das 《International Journal of Theoretical Physics》2002,41(6):1099-1106
In this paper we study coherent states and squeezed states in one mode interacting Fock space. 相似文献
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Within the algebraic frame of smeared photon fields, the coherence properties of squeezed multi-photon states are elaborated. The squeezing Bogoliubov automorphisms are constructed by means of suitable one-mode symplectic transformations in the infinite-dimensional test-function space. Transposed into the state space, these transformations are shown to preserve first-order coherence when applied to coherent, classical, Fock-normal states in spite of rendering them nonclassical. The cases, where first-order coherence is destroyed, are also classified. Very special conditions on the initial state modes and on the operation parameters are worked out, under which even second-order coherence is still valid for the transformed classical coherent states, in spite of exhibiting squeezed fluctuations. 相似文献
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The purpose of the present paper is to analyze correlation structures of the ground states of the Schrödinger operator. We construct Griffiths inequalities for the ground state expectations by applying operator-theoretic correlation inequalities. As an example of such an application, we study the ground state properties of Schrödinger operators.
相似文献11.
Hong-Chun Yuan Heng-Mei Li Ye-Jun Xu Hong-Yi Fan 《International Journal of Theoretical Physics》2009,48(12):3319-3330
A class of generalized two-mode squeezed states |φ〉 is presented, which are generated from the generalized two-mode squeezing operator U(γ,λ) acting on the two-mode coherent state |α
1,α
2〉. We first investigate some mathematical properties of U(γ,λ) including the squeezing transformation under U(γ,λ), ket-bra integral form in the coordinate representation, normally ordered form. Then we evaluate some nonclassical characteristics
of the state |φ〉 such as higher-order squeezing behavior, entanglement analysis and analytical expression of the Wigner function. 相似文献
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引入平移激发压缩真空态D(z)a\+\{+m\}S(r)|0〉,并讨论它的一些基本性质.利用正规 乘积内的积分技术,证明了其完备性.平移激发以后,与压缩真空态相比较,光子数分布 的振荡性质更加显著.与压缩真空态的光子总是聚束的性质不同,在平移参量|z|和激发 数m都较小时,平移激发压缩真空态的光子统计关联可以呈现反聚束效应.计算了它的准 概率分布函数(Q函数和Wigner函数),并讨论了它们对各参量的依赖关系,从Wigner函数可 以清楚地看出该量子态的非经典特性.
关键词: 相似文献
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WEN Yi-Huo LONG Gui-Lu 《理论物理通讯》2008,49(5):1207-1210
We propose a scheme for generating squeezed states in solid state circuits which consist a superconducting transmission line resonator (STLR), a superconducting Cooper-pair box (CPB) and a nanoelectromechanical resonator (NMR). The nonlinear interaction between the STLR and the CPB can be implemented by setting the external biased flux of the CPB at some certain points. The interaction Hamiltonian between the STLR and the NMR is derived by performing Fr ohlich transformation on tile total Hamiltonian of tile combined system. Just by adiabatically keeping the CPB at the ground state, we get the standard parametric down-conversion Hamiltonian, and the squeezed states of the STLR can be easily generated, which is similar to the three-wave mixing in quantum optics. 相似文献
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FAN Hong-Yi WANG Hui 《理论物理通讯》2001,(10)
We discuss the entanglement swapping of two pairs of displaced two-mode squeezed states and find that the squeezing parameter of the outcoming squeezed state is less than that of the originM squeezed states. The calculation is greatly simplified by virtue of the natural expression of the two-mode squeezing operator in EPR eigenstate representation. A protocol for such entanglement swapping is proposed.`` 相似文献
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Based on the Husimi operator in pure state form introduced by Fan et al., which is a squeezed coherent state projector, and the technique of integration within an ordered product (IWOP) of operators, as well as the entangled state representations, we obtain the Husimi functions of the excited squeezed vacuum states (ESVS) and two marginal distributions of the Husimi functions of the ESVS. 相似文献
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Based on the Husimi operator in pure state form introduced by Fan et al., which is a squeezed coherent state projector, and the technique ofintegration within an ordered product (IWOP) of operators, as well as theentangled state representations, we obtain the Husimi functions of theexcited squeezed vacuum states (ESVS) and two marginal distributions of theHusimi functions of the ESVS. 相似文献
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Higher Order Squeezed States of Anharmonic Oscillators 总被引:1,自引:0,他引:1
Ji-Suo Wang Tang-Kun Liu Ming-Sheng Zhan 《International Journal of Theoretical Physics》2000,39(11):2583-2593
In this paper the N eigenstates of the Nth powers (N 3) of the annihilationoperator of an anharmonic oscillator are constructed and their completeness isinvestigated. We introduce a new kind of higher order squeezing, Mth-order SU(1,1) squeezing. The properties of Mth-order SU(1, 1) squeezing and anticorrelationof the N states are studied. The result show that these states may form a completeHilbert space; the Mth-order [M = (n + 1/2)N;n = 0,1, ...] SU(1, 1) squeezingeffects exist in all of the N states when N is even. There is anticorrelation in allof them. 相似文献
19.
We present a new concise approach for normalizing m-photon-added squeezed state a^tmS(s)|0〉≡|r〉m and mphoton-subtracted squeezed state a^m S ( r ) |0〉) ≡ |r〉m, i.e., we construct the generating function ∑m=0^∞ t^m/m!m〈r|r〉m and ∑m=0^∞ t^m/m!_m〈r|r〉_m respectively, after calculating them and comparing the result with the standard form of generating function of Legendre polynomials Pm, we find m〈r|r〉m=m!cosh^m rPm(cosh r),amd _m〈r|r〉_m=m! (-i sinh r)^ m pm ( i sinh r), where r is the squeezing parameter. 相似文献
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References: 《理论物理通讯》2007,47(2):325-329
We introduce the coordinate-dependent two-mode squeezing transformations and discuss the properties of the corresponding two-mode squeezed states. 相似文献