共查询到20条相似文献,搜索用时 15 毫秒
1.
In this work, we mainly investigate effect of PT-symmetric operation on the dynamic behavior of the relative entropy of coherence for a two-level system within non-Markovian environments and put forward a feasible physical scheme to recover coherence by utilizing optimal PT-symmetric operation. The results show that the damaged quantum coherence can be effectively restored under influence of the non-Markovian regimes. Furthermore, the freezing phenomenon of the coherence can be detected by using the optimal PT-symmetric operation strength within the non-Markovian environments.
相似文献2.
This paper presents a quantum mechanical formalism of the classical coherence theory, within which the generalized radiance function defined in the time domain is regarded as a phase space representative of a time-dependent correlation operator of a polychromatic field. The theory deals with both stationary and nonstationary fields and, for a stationary field, provides a new operator formalism of the usual theory of optical coherence developed in the space-frequency domain. New results include an operator representation of the mutual coherence function, an operator version of the Wiener-Khintchine theorem, and an operator theorem that projects the correlation operator of a polychromatic field onto a particular spectral component. As illustrative examples, the previous formulas regarding the relationship between temporal coherence and spatial coherence, and the relationship between spectral properties and coherence properties are derived from the new operator formulas. The correspondence of the present formalism to the usual formalism using Dirac notation to describe the propagation of a stationary, partially coherent, quasi-monochromatic field is also considered. 相似文献
3.
Koji Nagata 《中国物理快报》2010,(3):29-32
We review the historical fact of multipartite Bell inequalities with an arbitrary number of settings. An explicit local realistic model for the values of a correlation function, given in a two-setting Bell experiment (two-setting model), works only for the specific set of settings in the given experiment, but cannot construct a local realistic model for the values of a correlation function, given in a continuous-infinite settings Bell experiment (infinite-setting model), even though there exist two-setting models for all directions in space. Hence, the two-setting model does not have the property that the infinite-setting model has. Here, we show that an explicit two-setting model cannot construct a local realistic model for the values of a correlation function, given in an M-setting Bell experiment (M-setting model), even though there exist two-setting models for the M measurement directions chosen in the given M-setting experiment. Hence, the two-setting model does not have the property that the M-setting model has. 相似文献
4.
Stefan Weigert 《Czechoslovak Journal of Physics》2004,54(1):147-149
The eigenstates of a diagonalizable PT-symmetric Hamiltonian satisfy unconventional completeness and orthonormality relations. These relations reflect the properties of a pair of bi-orthonormal bases associated with non-hermitean diagonalizable operators. In a similar vein, such a dual pair of bases is shown to possess, in the presence of PT symmetry, a Gram matrix of a particular structure: its inverse is obtained by simply swapping the signs of some its matrix elements. 相似文献
5.
《中国物理快报》2020,(4)
A quantum system in complex potentials obeying parity-time(PT) symmetry could exhibit all real spectra,starting out in non-Hermitian quantum mechanics. The key physics behind a PT-symmetric system consists of the balanced gain and loss of the complex potential. We plan to include the nonequilibrium nature(i.e., the intrinsic kinds of gain and loss of a system) to a PT-symmetric many-body quantum system, with an emphasis on the combined effects of non-Hermitian due to nonequilibrium nature and PT symmetry in determining the properties of a system. To this end, we investigate the static and dynamical properties of a dark soliton of a polariton Bose–Einstein condensate under the PT-symmetric non-resonant pumping by solving the drivendissipative Gross–Pitaevskii equation both analytically and numerically. We derive the equation of motion for the center of mass of the dark soliton's center analytically with the help of the Hamiltonian approach. The resulting equation captures how the combination of the open-dissipative character and PT-symmetry affects the properties of the dark soliton; i.e., the soliton relaxes by blending with the background at a finite time. Further numerical solutions are in excellent agreement with the analytical results. 相似文献
6.
基于Z变换的局部匀速运动模糊图像恢复算法 总被引:2,自引:0,他引:2
针对背景不变的局部匀速运动模糊图像复原问题,提出一种基于Z变换的恢复算法.在前景和背景色差较大的假设前提下,基于背景差方法将前景从图像中分离出来;利用旋转矩阵将前景在像平面内任意方向的运动转换成X轴方向的运动;进而把复杂的局部模糊恢复问题简化为前景模糊恢复及前景和背景融合两个子问题来解决,使求解过程得到最大程度简化;在严格的数学推导基础上建立基于Z变换的退化及恢复模型,将模型中的差分方程转化为简单的代数方程求解;仿真结果表明,提出的算法能正确、有效并且快速地恢复由于局部匀速运动所造成的图像退化;算法对模糊宽度的变化不敏感,较维纳滤波恢复算法有一定的稳健性、优越性. 相似文献
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Tsutomu Ichimura Naoki Anndo Tadayuki Funaba Shigeru Endo Yoshiki Odagiri Naohiro Tan-no Humio Inaba 《Optical Review》1996,3(1):38-46
We propose and confirm a novel technique of optical frequency domain reflectometry based on multidigitized coherence using a multimode laser. The proposed system can easily provide the potential for high resolution on the order of 10 μm without scanning frequencies as in frequency domain reflectometers of either continuous or stepwise sweep. The theoretical approach agrees well with the experimental results demonstrated using a commercially available multimode laser diode. 相似文献
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Based on the technique of integration within an ordered product of operators, the Weyl ordering operator formula is derived and the Fresnel operators' Weyl ordering is also obtained, which together with the Weyl transformation can immediately lead to Eresnel transformation kernel in classical optics. 相似文献
11.
Seon Young Ryu Hae Young Choi Jihoon Na Eunseo Choi Gil-Ho Yang Byeong Ha Lee 《Optical and Quantum Electronics》2005,37(13-15):1191-1198
We report a photonic crystal fiber (PCF)-based optical coherence tomography (OCT) system, in which conventional single-mode fiber for the transmission line and the fiber coupler for the beam splitter/combiner are replaced with PCF and PCF coupler. The PCF coupler fabricated using the fused biconical tapered (FBT) method showed a nearly flat coupling ratio over a broad spectral bandwidth of 400 nm, which provided an axial resolution of 3-μm for OCT imaging. With a white-light source, the 8-μm thick air gap between two stacked cover glasses was measured, and with a conventional superluminecent diode (SLD) source, the in vitro images of rat eye and Misgurnus mizolepis skin were successfully obtained. The PCF and PCF coupler might enable a white-light as the source for the cost effective and high-resolution OCT system. 相似文献
12.
We consider a CNOT gate operation under the influence of quantum bit-flip noise and demonstrate that ac fields can change the qubit Hamiltonian in such a way that it approximately commutes with the bath coupling. Then the noise effectively acts as phase noise which improves coherence up to several orders of magnitude while the gate operation time remains unchanged. Within a high-frequency approximation, both purity and fidelity of the gate operation are studied analytically. The numerical treatment with a Bloch-Redfield master equation confirms the analytical results. 相似文献
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We have proposed an optical information processing system adopting synthesis of the optical coherence function by using direct frequency-modulation of a laser diode.1’ Optical coherence function having notch shape is discussed theoretically and experimentally. Applying the notch shaped coherence function to this system, to mask selectively a two-dimensional (2-D) information from a three-dimensional (3-D) object can be carried out. After showing the experimental results on selective masking, the performance deterioration factors are discussed in detail. 相似文献
15.
光学相干层析系统相干传递函数研究 总被引:4,自引:1,他引:4
在弱物体近似下从成像系统角度对光学相干层析测量技术进行了理论研究。分析了该技术测量样品纵深结构时图像的形成机理。结果表明它相当于一复振幅线性平移不变系统,从而可用相干传递函数描述系统性能,所得相干传递函数表明系统具有低通特性,半峰值带宽△k=2△λ/λ^2。由于物体频谱整体平移了1/λ,测量的是纵向结构的高频信息。本文的工作为定量分析光学相干层析对未知结构的测量结果及进一步提高空间分辨率提供了理论 相似文献
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We report on the spectroscopic optical coherence tomography of highly scattering media using a parallel detection scheme incorporated
with an ultrabroadband femtosecond Ti:sapphire laser in the range of 700--880 nm. A plurality of spectrally-resolved reflectance
profiles are simultaneously measured in a single longitudinal scan, from which information on the spectral content of the
sample is derived. Differential absorption measurements of scattering media with known characteristics are performed to demonstrate
the potential use in quantitative analysis. 相似文献
18.
Yoshiaki Yasuno Yusuke Sando Jun-ichiro Sugisaka Takashi Endo Shuichi Makita Gouki Aoki Masahide Itoh Toyohiko Yatagai 《Optical and Quantum Electronics》2005,37(13-15):1185-1189
We introduce a numerical in-focus Fourier-domain optical coherence tomography(in-focus FD-OCT) which can measure cross-sectional images of samples with the high lateral resolution comparable with the resolution in the focal plane in overall range of measurement. In this method, the lateral resolution is enhanced by lateral signal processing of a complex OCT image obtained with FD-OCT. Quantitative evaluation of this method and application to measurement of a porcine eyeball are presented. 相似文献
19.
In this paper, we study coherence-induced state ordering with Tsallis relative entropy of coherence, relative entropy of coherence and l1 norm of coherence, and give the sufficient conditions of the same state order induced by above coherence measures. First, we show that the above measures give the same ordering for single-qubit states in some special cases. Second, we consider some special states in a d-dimensional quantum system. We show that the above measures generate the same ordering for these special states. Finally, we discuss dynamics of coherence-induced state ordering under Markovian channels. We find amplitude damping channel changes the coherence-induced ordering even though for single-qubit states with fixed mixedness. 相似文献
20.
The coherence properties of sunlight were first studied by Verdet around 1869 and were later examined by other scientists. However, all the previous calculations assumed that the Earth is in the far zone of the Sun, an assumption that is incorrect. An investigation of why Verdet's result is nevertheless correct reveals a surprising property of radiation from incoherent sources. 相似文献