共查询到20条相似文献,搜索用时 62 毫秒
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研究了强度差测量方案下,探测器量子效率对光子数态、关联数态、压缩真空态三种量子光源注入的马赫-曾德尔干涉仪相位测量灵敏度的影响.获得了相位测量灵敏度与效率的定量关系,比较了探测效率对不同量子态注入的干涉仪相位灵敏度的影响.研究表明:光子数态注入时,相位测量灵敏度始终不能超越标准量子极限;关联数态注入时,无论多大的光子数,要获得相位测量的量子增强,探测效率不得小于75%;对于压缩真空态,只要有压缩存在就可以获得一定的相位测量的量子增强;关联数态、压缩真空态的注入,相位灵敏度皆随探测效率的增大而不同程度的提高,且压缩真空态比关联数态具有更好的量子增强效果.给出了在量子增强的精密测量实验中对探测效率的要求,并结合实际应用说明了探测效率的提高有助于提高干涉仪探测的灵敏度. 相似文献
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利用量子技术增强Sagnac效应提高陀螺输出精度具有重要的研究意义, 是实现全自主导航的重要途径. 以相干态激光作为输入光源的光学陀螺因真空零点波动使其输出精度限制于散粒噪声极限而难以提高. 为减小真空波动的影响, 提出在激光输入的分束器的另一输入端输入压缩真空光并结合平衡零拍探测技术的方法增强Sagnac效应. 理论分析表明Sagnac效应性能得到有效提升: 干涉输出的灵敏度检测极限和动态范围均随着压缩程度的增加而呈指数级增长. 该方法只需对经典光学陀螺做少量改动就可实现, 是提高光学陀螺输出精度的一种新方法. 相似文献
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Super-resolution and super-sensitivity of entangled squeezed vacuum state using optimal detection strategy 下载免费PDF全文
Interference metrology is a method for achieving high precision detection by phase estimation. The phase sensitivity of a traditional interferometer is subject to the standard quantum limit, while its resolution is constrained by the Rayleigh diffraction limit. The resolution and sensitivity of phase measurement can be enhanced by using quantum metrology. We propose a quantum interference metrology scheme using the entangled squeezed vacuum state, which is obtained using the magic beam splitter, expressed as |ψ〉=(|ξ〉|0〉+|0〉|ξ〉)/(2+2/coshr)~(1/2), such as the N00 N state. We derive the phase sensitivity and the resolution of the system with Z detection, project detection, and parity detection. By simulation and analysis, we determine that parity detection is an optimal detection method, which can break through the Rayleigh diffraction limit and the standard quantum limit. 相似文献
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We explore the general characteristics of a matter-wave Sagnac interferometer in a two-parameter estimation scheme. We find that the measurement precisions of both parameters cannot reach the Heisenberg limit (HL) simultaneously when the input state is maximally entangled. Only one of the parameters’ uncertainties can approach the HL while the other is scaled by the standard quantum limit. We provide the conditions with which the measurement precision of the specific parameter can reach the HL. We also discuss and figure out the concrete expressions of the constraint conditions for saturating the quantum Cramér–Rao bound. To satisfy these constraint conditions, the evolution time has to be a series of discrete values. Additionally, we calculate the variances of the parameters through some examples under these constraint conditions. The results provided in our work show some intrinsic features of the matter-wave Sagnac interferometer for the two-parameter estimation, which can be valuable in actual experiments. 相似文献
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The laser interferometric gravitational-wave detectors are sensitive to the quantum state of light employed in the dark port of interferometric system. In this paper a general quantum state for the dark input port is assumed. The quantum state of light is expanded versus the Fock states. The quantum noise of interferometric system is computed as a function of the quantum state of light. The variational method and the genetic algorithm are employed to determine the coefficients of the dark input port and the laser input power for the minimization of the quantum noise. Calculation shows that the optimum quantum state for the dark input port is very close to the vacuum squeezed state. For this optimum quantum state the quantum noise and optimum laser power reduces one order of magnitude relative to the conventional interferometer. 相似文献
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J. Fade N. Treps C. Fabre P. Réfrégier 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(2):215-227
Non-classical quantum effects allow light with local
sub-Poissonian fluctuations below shot noise to be produced. We show
that using such light can improve the estimation precision of a
parameter in an image beyond the standard Poissonian limit. This
benefit is theoretically investigated by means of a phenomenological
model of local sub-Poissonian noise which assumes the independence
of the fluctuations in each pixel. In particular, a bound on the
best precision expectable independently of the exact unbiased
estimation protocol used, which is given by the Cramer-Rao bound, is
determined from this model. The numerical simulations presented in
the special case of the estimation of a displacement of an image
perturbed with local sub-Poissonian noise show that a standard
estimator can overcome the classical Poissonian limit by reaching
this limit precision only beyond a certain value of the photon flux
which we characterize. We eventually present some numerical results
that demonstrate the generality of the model proposed, of the
optimality bounds and of the estimator performance. 相似文献
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Stable, low noise, infrared squeezed state tight at 1064 nm is generated by utilizing optical parametric down-conversion (OPDC)
technique based on periodically poled KTiOPO4 in a optical parametric amplifier (OPA) resonator. A non-classical noise reduction of 2.58 dB below the shot noise is observed
through balanced homodyne detection. The squeezed state light is used to set up an imaging system for high-resolution imaging,
and it is found that the resolution of image based on the amplitude-squeezed light is 1.26 times larger than that of infrared
coherent light under the same intensity. The experimental results indicate that squeezed light is an important non-classical
light, which can overcome the coherent laser shot-noise, the classical diffraction limit and limit of quantum noise. 相似文献
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An interferometric detection scheme to measure optical phase shift with sensi tivity beyond the shot noise limit is proposed. The theoretical calculation shows that using the quantum correlated twin beams produced from an optical parametric amplifier as the input fields of a Mach-Zehnder interferometer, the minimum detectable phase shift will exceed the shot noise limit N-1/2 and approach the Heisenberg limit N-1. The parametric dependences of the minimum detectable phase shift on the nonlinear interaction, input photon number, and detection efficiency are shown. 相似文献
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F. Y. Hou L. Yu X. J. Jia Y. H. Zheng C. D. Xie K. C. Peng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,62(3):433-437
We report the experimental generation of the optical non-classical states with
1.34 μm wavelength which is close to one of the fiber telecommunication
windows (1.31 μm). The single-mode amplitude squeezed states with quantum
fluctuation of 2.3 ± 0.1 dB below the shot noise limit (SNL) and the entangled
states with quantum correlation of 1.1 ± 0.1 dB below the SNL are produced by an optical
parametric amplifier with a type-I phase-matched PPKTP crystal and a pair of properly
oriented type-II phase-matched KTP crystals, respectively. 相似文献
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Phase noise due to thermodynamic fluctuations in the optical path length is evaluated in this paper for basic fibre interferometers. In Mach-Zehnder and Michelson interferometers, where the temperature phase fluctuation (TPF) is that intrinsic to the fibre, this noise has been reported to be comparable to shot noise and a possible limit to sensor sensitivity in practical cases. We show that in Sagnac interferometers, used in fibre gyro and in Faraday current sensors, the TPF noise is decreased with respect to that intrinsic to the fiber because propagation in the same optical path leads to a correlation of the phase fluctuations. In addition, we show that in Fabry-Perot and ring resonators, as multiple reflections increase the effective path length, TPF noise is enhanced and can be dominant over shot noise even for moderate fibre lengths. 相似文献
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H.A. Bachor 《Applied physics. B, Lasers and optics》2005,80(7):889-896
The quantum properties of light play an ever increasing role in optics. Thanks to the ability to generate and use special
light with modified quantum noise and to the generation of optical entanglement, we can now avoid the conventional limits
imposed by the shot noise. In addition, we can create new quantum information protocols. This article concentrates on the
case of continuous laser beams, which are used in many precision measurements and applications. The article summarizes some
of the concepts, reviews the technical development, provides a simple and reliable model and shows some of the current directions
of using optical quantum correlations, such as for the storage of quantum information.
PACS 42.50.Dv 相似文献
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E. Giacobino C. Fabre A. Heidmann R. Horowicz S. Reynaud D. Grandclément G. Grynberg M. Pinard 《Hyperfine Interactions》1987,37(1-4):109-124
It is shown that oscillators using nearly degenerate parametric conversion or four-wave mixing in the phase conjugation geometry
generate pairs of highly correlated photons. The intensity difference of the two corresponding light beams is then expected
to be below the shot noise limit. This property can be used to produce intensity stabilized light beams below the quantum
limit.
The phases of the twin beams also exhibit interesting correlation properties which will be discussed. Moreover, the combination
of the twin beams gives a squeezed state, which has been observed by other authors when the device is below the oscillation
threshold. We will describe preliminary results of experiments performedabove oscillation threshold. 相似文献
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The shot noise of a parallel double quantum dot (DQD) system under the perturbation of microwave fields is investigated in the weak Kondo regime. Peak-valley structures exhibit in the differential conductance and shot noise, and side resonant peaks emerge around the Kondo peak due to the absorption and emission of photons. The shot noise is sensitively dependent on the adjusting approach through changing the gate voltages. Large resonant Fano factor accompanying photon-induced side peaks appear by simultaneously varying the two gate voltages. The photon suppression and enhancement of shot noise have been evaluated corresponding to the coherent and incoherent current correlation. The destructive interference causes the suppression of shot noise by changing the Aharonov–Bohm phase. 相似文献
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Quantum metrology overcomes standard precision limits and has the potential to play a key role in quantum sensing. Quantum mechanics, through the Heisenberg uncertainty principle, imposes limits on the precision of measurements. Conventional bounds to the measurement precision such as the shot noise limit are not as fundamental as the Heisenberg limits, and can be beaten with quantum strategies that employ ‘quantum tricks’ such as squeezing and entanglement. Bipartite entangled quantum states with a positive partial transpose (PPT), i.e., PPT entangled states, are usually considered to be too weakly entangled for applications. Since no pure entanglement can be distilled from them, they are also called bound entangled states. We provide strategies, using which multipartite quantum states that have a positive partial transpose with respect to all bi-partitions of the particles can still outperform separable states in linear interferometers. 相似文献
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Shot noise measurements provide information on particle charge and its correlations. We report on shot noise measurements in a generic quantum dot under a quantized magnetic field. The measured noise at the peaks of a sequence of conductance resonances was some 9 times higher than expected, suggesting bunching of electrons as they traverse through the dot. This enhancement might be mediated by an additional level, weakly coupled to the leads or an excited state. Note that in the absence of a magnetic filed no bunching had been observed. 相似文献