二维谐振子位相相干态及数相算符的四阶压缩效应

本文利用Ｐｅｇｇ－Ｂａｒｎｅｔｔ的量子相位理论和有限维空间谐振子位相相干态的概念，研究了二维谐振子位相相干态及数相算符在此位相相干态中的四阶压缩效应。研究结果表明，在此类位相相干态中的数相算符均可呈现出四阶压缩效应。     

截头相干态的位相性质

使用文献中给出的计算量子位相统计性质的方法 ,计算了不同m值时截头相干态 ｜α ,m〉的PB量子位相统计性质 ,得出了不同场强下对位相性质有显著影响的数态     

非简谐振子广义相干态的位相统计性质

根据Pegg-Barnett位相定义,计算了非简谐振子广义相干态的位相概率分布函数,并且进行了数值计算。研究表明:广义相干态位相分布曲线随φ变化呈周期性,曲线峰值随|β|的增大而增大。     

仲玻色子相干态的叠加态压缩特性

对仲玻色子相干态的叠加态振幅压缩特性的研究，给出了压缩系数与叠加系数之间的关系，奇偶相干态、相干态的叠架态和仲玻色子奇偶相干态的有关结果均作为特例包含在本文的一般结论之中。     

单模压缩奇偶相干态的四次方压缩特性

用单模压缩算子作用在单模奇偶相干态上即可得到单模压缩奇偶相干态.本文研究了这类量子态的四次方压缩特性,结果表明单模压缩奇偶相干态存在很强的四次方压缩特性,并且压缩程度随着压缩参量r的增大而增强.     

压缩奇偶相干态的制备

提出一种借助A型三能级原子和单模腔场的Raman相互作用制备压缩奇偶相干态的新方案，在此方案中采取了压缩相干态在相干态的展开式，从而简化了方案步骤。     

奇偶相干态的熵压缩

研究了奇偶相干态的位置熵和动量熵的压缩特性 ,并讨论了位置熵压缩、动量熵压缩与广义坐标、广义动量压缩性的关系 .结果表明 ,与方差压缩不同 ,奇偶相干态的位置熵和动量熵都会表现出压缩性 .     

二能级原子与位相相干态光场的相互作用及跃迁几率

运用J－C模型研究了二能级原子与位相相干态光场的相互作用，以及光场－原子体系内部状态间的跃迁几率。     

原子位相算符公式的数值验证及性质讨论

引言我们在文献[1]中类比场相干态的位相定义,在用双玻色子表示的角动量态基础上,定义了原子相干态的位相算符并计算了其本征态和cosφ、sinφ等在原子相干态中的期望值。由于原子态中的“位相”是一种新定义,从多种角度核实其正确性是必要的。本文先对原子相干态中几个位相算符期望值给出计算结果,然后进一步给出位相和角动量间的测不准关系,再导出位相算符在角动量态中的表现,探讨了算符的物理意义和经典行为。     

奇偶相干态的非经典性质

计算了奇偶相干态的测不准关系,并讨论了它们的非经典性质,特别是偶相干态的非经典性质.偶相干态在一定区域内呈现压缩效应,而奇相干态没有这种性质.     

强度耦合的广义Jaynes-Cummings 模型中相干态的周期性复原效应

考察了依赖强度耦合的广义Jaynes-Cummings模型.假定初始时光场是相干态、原子处于相干迭加作者发现,在相位匹配条件下,初始场的相干态展示周期性的复原效应.同时,还证明了在描写光场的相干性方面,光场的量子相位与量子相干性是并协的.?烫     

Coherent quantum state storage and transfer between two phase qubits via a resonant cavity

As with classical information processing, a quantum information processor requires bits (qubits) that can be independently addressed and read out, long-term memory elements to store arbitrary quantum states, and the ability to transfer quantum information through a coherent communication bus accessible to a large number of qubits. Superconducting qubits made with scalable microfabrication techniques are a promising candidate for the realization of a large-scale quantum information processor. Although these systems have successfully passed tests of coherent coupling for up to four qubits, communication of individual quantum states between superconducting qubits via a quantum bus has not yet been realized. Here, we perform an experiment demonstrating the ability to coherently transfer quantum states between two superconducting Josephson phase qubits through a quantum bus. This quantum bus is a resonant cavity formed by an open-ended superconducting transmission line of length 7 mm. After preparing an initial quantum state with the first qubit, this quantum information is transferred and stored as a nonclassical photon state of the resonant cavity, then retrieved later by the second qubit connected to the opposite end of the cavity. Beyond simple state transfer, these results suggest that a high-quality-factor superconducting cavity could also function as a useful short-term memory element. The basic architecture presented here can be expanded, offering the possibility for the coherent interaction of a large number of superconducting qubits.     

广义含谐振子的含时粒子数表象及绝热量子相位和绝热含时相干态

直接定义广义含时谐振子的产生、湮灭算符,从而建立了该系统的含时粒子数表象．在此表象中很方便求得系统的绝热量子相位、找到它的绝热含时相干态,并对相干态的一些重要性质进行了讨论     

Coherent quantum phase slip

A hundred years after the discovery of superconductivity, one fundamental prediction of the theory, coherent quantum phase slip (CQPS), has not been observed. CQPS is a phenomenon exactly dual to the Josephson effect; whereas the latter is a coherent transfer of charges between superconducting leads, the former is a coherent transfer of vortices or fluxes across a superconducting wire. In contrast to previously reported observations of incoherent phase slip, CQPS has been only a subject of theoretical study. Its experimental demonstration is made difficult by quasiparticle dissipation due to gapless excitations in nanowires or in vortex cores. This difficulty might be overcome by using certain strongly disordered superconductors near the superconductor-insulator transition. Here we report direct observation of CQPS in a narrow segment of a superconducting loop made of strongly disordered indium oxide; the effect is made manifest through the superposition of quantum states with different numbers of flux quanta. As with the Josephson effect, our observation should lead to new applications in superconducting electronics and quantum metrology.     

叠加相干态的熵压缩特性

研究了叠加相干态的位置熵和动量熵的压缩特性，并运用数值方法计论了相干态强度、相位角和叠加参数对叠加相干态位置熵和动量熵压缩特性的影响。结果表明，叠加相干的位置熵和动量熵均可呈现压缩性，熵压缩度与相干态强度、相位角和叠加参数均有关系，相干态的相位角对场熵压缩的影响最大。     

谐振子与薛定谔相干态及不确定度

薛定谔相干态被定义为其坐标与动量平均值的演化与经典解相同的量子态。证明谐振子的任何状态都是薛定谔相干态。并计算了它们的不确定度,指出最小不确定度的态正是Ｇｌａｕｂｅｒ相干态,同时证明了对非谐振子一般不存在薛定谔相干态。     

高斯型调制相干态的零差测量原理

对高斯型调制相干态的零差测量技术进行分析,认为用平衡零差探测效果最佳。在量子力学的框架下,研究零差探测技术测量高斯型调制相干态的原理,确定光子数与相位的关系,阐述相干态的测量技术,分析了测量信号及其方差。     

相位平移算符及相位相干态

利用有限维的Ｐ－Ｂ相位算符，定义相位的湮灭和产生算符ψ，ψ＾＋。将此算符与粒子数的湮灭和产生算符ａ，ａ＾＋相比较，由其相似性可引进相应的相位平移算符。将此算符作用在零相位态上得相位相干态，最后讨论此相干态的性质。     

原子腔场系统中弱相干态的几率传送

提出了一个用原子与腔场纠缠态作为量子信道,非贝尔态测量和腔量子电动力学技术实现弱相干态的隐形传送的方案,分析了平均光子数对传送相干态的影响,发现平均光子数在0.25附近时效果最佳.该方案的最大优点是在某种程度上可以避免退相干现象.