一种改进的单帧图像超分辨率重建的高效算法

根据图像的降质模型,基于凸集投影(POCS)原理,结合降质图像模型,提出一种使用中值滤波初值处理的高效POCS单帧图像的超分辨率重建方法.计算机仿真结果表明,和双线性内插、经典POCS方法比较,改进后的该方法重建图像信噪比平均提高2.1 dB和1.1 dB.     

二维各向同性谐振子的升,降算子

本文利用二维各向同性谐振子在粒子数表象中的升、降算子，推导出在坐标表象中二维各向同性谐振子的升、降算子，本文所用方法简单、直观，很容易求出在坐标表象中升、降算子的表示形式。     

一种改进的雾天降质图像的清晰化算法

为了提高有雾天气下户外监控系统的能见度,提出一种改进的雾天降质图像清晰化算法.该算法从图像增强的角度入手,利用移动模板对各局部区域进行部分块重叠直方图均衡化以实现清晰化处理,克服了原算法运行时间过长的缺陷.实验表明,改进算法能够有效提高雾天降质图像的对比度,获得满意的视觉效果.     

三维各向同性谐振子的升、降算子

本文利用在粒子数表象中三维各向同性谐振子的升、降算子、推导出在坐标表象中三维各向同性谐振子的升、降算子并求出对三维各向性谐振的三个量子数（N,l,m)的升、降算子。     

一种改进的处理雾天降质图像的增强算法

子块部分重叠的局部直方图均衡算法(POSHE)用于雾天图像增强时,因为输出的图像亮度不可调整,致使有的图像处理后整体偏暗,部分细节不够清晰,为此,该文以POSHE为基础,利用抛物线直方图均衡化方法,实现雾天图像增强.实验表明该方法在对雾天降质图像处理时,可以达到局部细节清晰化和全局对比度增强的效果,并且亮度可方便调整.     

耦合谐振子的量子绝热捷径设计

量子绝热捷径技术旨在加快量子绝热慢过程,已经被广泛用于原子的冷却、转移等量子信息处理过程.研究耦合谐振子模型的量子绝热捷径设计及其热机应用,基于耦合谐振子模型的量子不变量,首先得到Ermakov方程,然后反设计耦合谐振子频率,最终加快绝热过程而不产生末态激发.本工作为耦合谐振子的量子态操控及超绝热量子热机提供了新思路.     

基于颜色校正和明暗通道的沙尘降质图像增强算法

针对沙尘天气下拍摄的图片中存在的颜色偏移、对比度低等问题,提出了一种沙尘降质图像增强算法.该算法由基于高斯模型的偏色校正和基于暗通道和亮通道的对比度增强2个部分组成.首先根据沙尘降质图像的RGB 3个通道直方图的分布特点,使用高斯模型分别对各通道进行建模,从而进行颜色调整,解决沙尘图像的偏色问题,其次采用暗通道先验去雾的原理,结合亮通道,计算像素级的大气光值,然后对透射图和大气光值进行优化,从而恢复出清晰的无沙尘图像,最后实验结果表明本文算法可以较好地提高沙尘降质图像的重建主观质量,并保持良好的色彩保真度和亮度.     

量子谐振子的经典类比

运用广义线性量子变换的普遍理论求解了量子谐振子 ,同经典谐振子类比给出了量子谐振子趋近于经典极限的条件 ,相干态是最理想的经典极限态 .     

量子相空间表象下的含时微扰理论

在Torres-Vega和Frederick(简称T-F)量子相空间的理论框架下,研究量子相空间表象下的量子跃迁问题.建立了T-F量子相空间表象下的含时微扰理论的基本公式,使之能符合相空间表象下的理论计算.以在含时外电场作用下的一维谐振子的跃迁为例进行了理论计算.结果表明:由该公式得到的计算结果是正确的,并对利用该计算结果做出的谐振子的第一激发态受微扰后的相空间中的几率密度分布图进行了讨论.     

基于饱和度的多尺度雾天降质图像质量增强算法研究

传统图像质量增强算法只适于薄雾状态下的降质图像,对浓雾状态下图像质量的增强效果较差。为此,提出一种新的基于饱和度的多尺度雾天降质图像质量增强算法,通过混合灰度转换函数子带分解多尺度Retinex算法挑选高、中、低三个尺度,结合雾天降质图像整体阴影区域和高光部分的细节,依次完成对雾天降质图像各个频段的质量增强,获取各个频段的质量增强结果。把获取结果与原图像共同视为一个图像集合,通过图像融合技术完成对所有图像的权重图分配操作,提高增强后图像质量。实验结果表明,所提算法能够有效增强雾天降质图像质量,主观客观评价结果均较优。     

基于广义卡尔曼-布西滤波的压缩光相位自适应估计方法

应用量子理论获取导航测角中的相位参数,有望获取超越经典理论极限的定位精度.在利用量子零拍探测测量相位压缩光的相位时,本振相位与待测相位在正交的前提下得到的零拍电流受到散粒噪声的影响最小.为了保证本振相位能够时刻满足此条件,并考虑到导航系统非线性和实时性的特点,基于广义卡尔曼-布西滤波设计了零拍锁相环,对本振相位进行实时的反馈控制,进而实现对压缩光相位的实时估计.理论分析以及仿真结果表明,利用压缩光作为信号场获取相位参数时能够突破散粒噪声的限制,提高导航测角系统的定位精度,并且在最优压缩度处相位估计精度最高,最优压缩度取决于压缩光强度以及测量系统的相位稳定性.      

基于庞加莱截面点的二阶混沌系统状态的定量判别

为增强对二阶混沌系统状态判别的效率与准确性,基于Duffing振子特性,利用庞加莱截面点密集程度作为其系统混沌状态的判据,构造相应函数模型用以定量表征其系统状态判据。利用特定参数下二阶混沌系统表现出的不同程度的周期特性,以策动力周期为采样周期对系统输出进行等周期频闪采样,获得庞加莱截面点。通过对固定数目的相邻样点离差均方值进行计算,定量表征出其样点分布的集中程度。通过进一步实验确定合适的阈值,实现混沌状态的判别。基于混沌的基本特征,实现从系统庞加莱截面点的角度进行混沌状态的判断,减小了运算复杂度,弱化了计算机数值解的计算误差的影响,增加检测准确度。通过选择合适系统初值与采样区间,缩短了采样时长,进而缩短判定时间,提高判定效率。后以二阶周期驱动的Duffing振子为例进行实验,得到实验结果,证明了此定量判别方法的可行性。通过复现前人实验并与本实验结果进行对比,突出本判定方法相比于前人,具有更高的准确度与更快的判定效率。     

Laser cooling of a nanomechanical oscillator into its quantum ground state

The simple mechanical oscillator, canonically consisting of a coupled mass-spring system, is used in a wide variety of sensitive measurements, including the detection of weak forces and small masses. On the one hand, a classical oscillator has a well-defined amplitude of motion; a quantum oscillator, on the other hand, has a lowest-energy state, or ground state, with a finite-amplitude uncertainty corresponding to zero-point motion. On the macroscopic scale of our everyday experience, owing to interactions with its highly fluctuating thermal environment a mechanical oscillator is filled with many energy quanta and its quantum nature is all but hidden. Recently, in experiments performed at temperatures of a few hundredths of a kelvin, engineered nanomechanical resonators coupled to electrical circuits have been measured to be oscillating in their quantum ground state. These experiments, in addition to providing a glimpse into the underlying quantum behaviour of mesoscopic systems consisting of billions of atoms, represent the initial steps towards the use of mechanical devices as tools for quantum metrology or as a means of coupling hybrid quantum systems. Here we report the development of a coupled, nanoscale optical and mechanical resonator formed in a silicon microchip, in which radiation pressure from a laser is used to cool the mechanical motion down to its quantum ground state (reaching an average phonon occupancy number of 0.85 ± 0.08). This cooling is realized at an environmental temperature of 20?K, roughly one thousand times larger than in previous experiments and paves the way for optical control of mesoscale mechanical oscillators in the quantum regime.     

Coherent dynamics of a flux qubit coupled to a harmonic oscillator

In the emerging field of quantum computation and quantum information, superconducting devices are promising candidates for the implementation of solid-state quantum bits (qubits). Single-qubit operations, direct coupling between two qubits and the realization of a quantum gate have been reported. However, complex manipulation of entangled states-such as the coupling of a two-level system to a quantum harmonic oscillator, as demonstrated in ion/atom-trap experiments and cavity quantum electrodynamics-has yet to be achieved for superconducting devices. Here we demonstrate entanglement between a superconducting flux qubit (a two-level system) and a superconducting quantum interference device (SQUID). The latter provides the measurement system for detecting the quantum states; it is also an effective inductance that, in parallel with an external shunt capacitance, acts as a harmonic oscillator. We achieve generation and control of the entangled state by performing microwave spectroscopy and detecting the resultant Rabi oscillations of the coupled system.     

压缩真空态的激发态下介观互感电容耦合双谐振电路的量子涨落

对介观互感电容耦合电路作双模耦合谐振子处理,将其量子化.通过三次幺正变换,将体系的哈密顿量对角化,给出了体系的本征能谱.研究了压缩真空的激发态下回路中电荷和电流的量子涨落.结果表明:这种量子涨落不仅与电路器件的参数、激发量子数、压缩参数有关,而且还和彼此的互感、电容耦合有关.     

Real-time quantum feedback prepares and stabilizes photon number states

Feedback loops are central to most classical control procedures. A controller compares the signal measured by a sensor (system output) with the target value or set-point. It then adjusts an actuator (system input) to stabilize the signal around the target value. Generalizing this scheme to stabilize a micro-system's quantum state relies on quantum feedback, which must overcome a fundamental difficulty: the sensor measurements cause a random back-action on the system. An optimal compromise uses weak measurements, providing partial information with minimal perturbation. The controller should include the effect of this perturbation in the computation of the actuator's operation, which brings the incrementally perturbed state closer to the target. Although some aspects of this scenario have been experimentally demonstrated for the control of quantum or classical micro-system variables, continuous feedback loop operations that permanently stabilize quantum systems around a target state have not yet been realized. Here we have implemented such a real-time stabilizing quantum feedback scheme following a method inspired by ref. 13. It prepares on demand photon number states (Fock states) of a microwave field in a superconducting cavity, and subsequently reverses the effects of decoherence-induced field quantum jumps. The sensor is a beam of atoms crossing the cavity, which repeatedly performs weak quantum non-demolition measurements of the photon number. The controller is implemented in a real-time computer commanding the actuator, which injects adjusted small classical fields into the cavity between measurements. The microwave field is a quantum oscillator usable as a quantum memory or as a quantum bus swapping information between atoms. Our experiment demonstrates that active control can generate non-classical states of this oscillator and combat their decoherence, and is a significant step towards the implementation of complex quantum information operations.     

压缩真空态的激发态下介观串并联RLC电路的量子涨落

将介观串并联RLC电路等效成阻尼谐振子并量子化,研究了压缩真空态的激发态、压缩真空态、真空态下电流和电压的量子涨落.结果表明,支路电流电压的量子涨落不仅与电路器件的参数有关,而且和激发量子数、压缩因子及压缩角有关,并随时间衰减.     

Fock态下介观电容耦合阻尼双谐振RLC电路的量子涨落

将介观电容耦合阻尼电路作双模耦合阻尼谐振子处理,使其量子化,通过3次幺正变换,将体系的哈密顿量对角化,并给出了体系的本征能谱.研究了Fock态、真空态下回路中电荷和电流的量子涨落.     

Nanometre-scale displacement sensing using a single electron transistor

It has been a long-standing goal to detect the effects of quantum mechanics on a macroscopic mechanical oscillator. Position measurements of an oscillator are ultimately limited by quantum mechanics, where 'zero-point motion' fluctuations in the quantum ground state combine with the uncertainty relation to yield a lower limit on the measured average displacement. Development of a position transducer, integrated with a mechanical resonator, that can approach this limit could have important applications in the detection of very weak forces, for example in magnetic resonance force microscopy and a variety of other precision experiments. One implementation that might allow near quantum-limited sensitivity is to use a single electron transistor (SET) as a displacement sensor: the exquisite charge sensitivity of the SET at cryogenic temperatures is exploited to measure motion by capacitively coupling it to the mechanical resonator. Here we present the experimental realization of such a device, yielding an unequalled displacement sensitivity of 2 x 10(-15) m x Hz(-1/2) for a 116-MHz mechanical oscillator at a temperature of 30 mK-a sensitivity roughly a factor of 100 larger than the quantum limit for this oscillator.