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1.
实验上展示了钇铁石榴石(YIG)晶体小球中磁振子与超导量子比特的驱动缀饰态之间的相干强耦合,磁振子的加入使得在超导量子比特中形成了双重缀饰态.实验中一个钇铁石榴石晶体小球与一个超导量子比特同时放置在三维谐振腔中,分别通过磁偶极相互作用和电偶极相互作用与谐振腔中的本征场(TE102模式)耦合,并通过腔模作为媒介实现两者之间的有效相干强耦合.给超导量子比特施加一个共振的微波驱动并改变驱动强度,测得耦合系统能级劈裂随驱动强度的变化,并理论上利用粒子-空穴对与玻色场耦合的模型做了计算.在大部分的驱动强度范围内实验结果都与理论计算结果符合得较好,表明驱动下的比特-磁振子耦合系统可以用来模拟粒子-空穴对称对与玻色场的耦合系统.本文使用的混合量子系统为模拟玻色子与费米子的混合系统提供了一个新途径. 相似文献
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超导量子比特以其在可控性、低损耗以及可扩展性等方面的优势被认为是最有希望实现量子计算机的固态方式之一.量子比特之间的相干可控耦合是实现大规模的量子计算的必要条件.本文介绍了超导量子比特耦合方式的研究进展,包括利用电容或电感实现量子比特的局域耦合,着重介绍一维传输线谐振腔作为量子总线实现多个量子比特的可控耦合的电路量子电动力学体系,并对最新的三维腔与超导量子比特的耦合结构的研究进展进行了论述.对各种耦合体系的哈密顿量进行了比较详细的分析,并按照局域性和可控性对不同耦合机制进行了分类. 相似文献
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用量子空腔耦合的超导电荷比特器件被认为是实现量子信息处理的相当有希望的体系之一.如何在这种可集成的量子体系中实现高保真度的操作是量子信息处理领域的重要课题.文章介绍作者最近提出的在量子腔耦合的超导量子比特中用具有内禀容错功能的几何操作来实现普适量子逻辑门,产生多比特量子纠缠及实现量子纠错编码的一个可行方案. 相似文献
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范云益潘佳政李永超戴欣魏兴雨卢亚鹏孙国柱吴培亨 《低温物理学报》2017,(3):35-39
我们在三维传输子量子比特系统中,通过施加与跃迁能级对应的强耦合场,同时,利用一弱探测场对系统的吸收谱进行了测量.发现在强耦合场的作用下,吸收谱会分裂成双峰,即探测到了Autler-Townes效应(ATE)现象.首先,我们利用单光子跃迁过程,测量了ATE分裂的大小和耦合场功率的关系.进一步,我们首次利用双光子跃迁过程进行了ATE的探测,分析了探测到的ATE分裂大小和耦合场的关系.我们通过QUTIP解得系统的密度矩阵,得到的理论的计算结果和实验结果十分符合. 相似文献
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把多个超导量子比特耦合起来并实现对它们的测控是实现超导量子计算的重要一步。作为“物理前沿介绍——超导量子计算”系列的第四篇,本文系统阐述超导量子比特耦合,操控与测量的物理原理,并给出了一套基本的量子操控与测量的流程。作为例子对新近一些超导量子比特实验的设计方案进行讨论,最后对超导量子比特测控基础表征过程给出统一的流程图,并对超导量子计算进行了展望。本文旨在帮助广大高校物理专业教师、高年级本科生、研究生以及对超导量子计算感兴趣的理工科背景读者系统了解操控与测量超导量子比特的物理原理。 相似文献
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与微米机械振子相比, 纳米机械振子使用纳米级材料制备, 尺寸更小, 质量更轻, 它作为探测器, 在探测力、质量等物理量时拥有更高的灵敏度. 石墨烯有高强度、 低密度等优良的机械特性, 被认为是制备纳米机械振子的理想材料. 基于其制备的石墨烯纳米机械振子有着高谐振频率、高品质因子和谐振频率可调性高等优势, 对于纳米力学的基础研究和应用都具有重要的意义. 本文利用微纳加工工艺(包括电子束曝光、 电子束蒸发镀膜、 反应离子刻蚀和微米级定点干法转移技术)制备了串联石墨烯纳米机械振子样品, 并在极低温下(10 mK) 测量了石墨烯机械振子的机械性质, 实现两个串联石墨烯纳米机械振子的强耦合, 耦合强度为1.34 MHz, 协同系数C = 399. 相似文献
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超导-量子点耦合系统的相干输运 总被引:1,自引:0,他引:1
研究超导-量子点耦合系统的量子相干输运,主要考虑系统在微波场及Zeeman场作用下的输运电流特性.应用BCS平均场理论及非平衡格林函数技术,对超导体各极作Bogoliubov变换使其对角化,从而推导出用格林函数表示的电流公式.对几种特殊情况进行数值分析,计算出电流-电压、电流-磁场及直流Josephson电流的共振隧穿曲线. 相似文献
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压电振子是新一代方位声波测井仪器中相控圆弧阵声波辐射器的重要组成部分。利用有限元法对构成圆弧阵的压电振子进行了设计分析,结果显示了压电振子存在多阶弯曲振动模态,且长度方向一阶弯曲振动能够满足方位声波测井的工作频率要求。针对长度方向一阶弯曲振动模式,数值模拟了几何尺寸对压电振子性能参数的影响。压电振子的谐振频率随着陶瓷片长度、基片或陶瓷片厚度的减小而降低;压电振子的辐射声功率随着陶瓷片长度或压电振子宽度的增加、基片或陶瓷片厚度的减小而增大;合理地选取长度和厚度可使压电振子具有较高的机电耦合系数。数值模拟结果可以对圆弧阵结构优化设计起到良好的指导作用。 相似文献
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算力是数字经济时代新的生产力。量子计算基于量子力学的规律进行计算,人们普遍相信它可以在不久的将来在某些问题上完成经典计算机所无法完成的计算任务,实现量子优越性。作为最有可能实现通用量子计算的平台之一,以约瑟夫森结为核心元件的超导量子比特,在量子控制和量子测量方面具有稳定、可靠、便于设计和扩展等独特的优势,受到科学界甚至产业界的广泛关注,正在高速发展。文章围绕约瑟夫森结这一具有非线性和无耗散特征的超导量子器件,阐述了超导量子比特的基本原理及结构特征,重点介绍超导量子芯片设计、加工方面的前沿进展,并对未来发展方向进行简单的展望。 相似文献
11.
We propose to implement a quantum switch scheme for coupling highly detuned superconducting qubits connected by a gap-tunable bridge qubit. By modulating the frequency of the bridge qubit, it can be used as a coupler to switch on/off and adjust the coupling strength between the initially non-interaction qubits. It is shown that the proposals of quantum information transfer and quantum entangled gate between two highly detuned qubits can be implemented with high fidelity. Moreover, we extend the case of coupling the switch to multiple qubits for the generation of W states. The advantages of our scheme are that it eliminates the need for tuning the gaps of the qubits and the cross-talk interaction is greatly suppressed. The influence of decoherence and parameter variation is also investigated by numerical simulation, which suggests that the present scheme is feasible in current experiment. 相似文献
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A new quantum computer algorithm is proposed for determining the parity of function f(x) by using quantum counting algorithm. The parity of function f(x) can be determined by counting exactly the number of satisfying f(x)=−1, which is equivalent to determine the number of solutions, M, to an N item search problem. The algorithm can be accomplished in time of order
. 相似文献
14.
Vinay Ambegaokar 《Journal of statistical physics》2006,125(5-6):1183-1192
The time development of the reduced density matrix for a quantum oscillator damped by coupling it to an ohmic environment
is calculated via an identity of the Debye-Waller form. Results obtained some years ago by Hakim and the author in the free-particle
limit(10) are thus recovered. The evolution of a free particle in a prepared initial state is examined, and a previously published
exchange(5,9) is illuminated with figures showing no decoherence without dissipation.
PACS number: 03.75.Ss 相似文献
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Inspired by Ying’s work on automata theory based on quantum logic and classical automata theory, we introduce the concepts
of reversal, accessible, coaccessible and complete part of finite state automata based on quantum logic. Some properties of
them are discussed. More importantly we investigate the recognizability and accessibility properties of these types on the
framework of quantum logic by employing the approach of semantic analysis.
Foundation: supported by the National Natural Science Foundation of China (No. 10671030). 相似文献
17.
An experimentally feasible strong coupling system between a spin ensemble and a superconducting qubit is studied. The coupling strength can be exponentially enhanced by applying the squeezing transformations to the system. By means of the two spin ensembles commonly coupled to a superconducting qubit, a set of universal nonadiabatic holonomic single‐qubit quantum gates can be realized in a decoherence‐free subspace. Furthermore, this proposal is robust with respect to decay of the system parameters, and it is experimentally feasible with currently available technology. 相似文献
18.
Using QHD model the parametric interaction of a laser radiation in an unmagnetised piezoelectric semiconductor has been studied. It is found that the Bohm potential in the electron dynamics enhances the gain coefficient of parametrically generated modes whereas reduces the threshold pump intensity. 相似文献
19.
Jamie Vicary 《International Journal of Theoretical Physics》2008,47(12):3408-3447
This paper describes how the structure of the state space of the quantum harmonic oscillator can be described by an adjunction
of categories, that encodes the raising and lowering operators into a commutative comonoid. The formulation is an entirely
general one in which Hilbert spaces play no special role.
Generalised coherent states arise through the hom-set isomorphisms defining the adjunction, and we prove that they are eigenstates
of the lowering operators. Generalised exponentials also emerge naturally in this setting, and we demonstrate that coherent
states are produced by the exponential of a raising morphism acting on the zero-particle state. Finally, we examine all of
these constructions in a suitable category of Hilbert spaces, and find that they reproduce the conventional mathematical structures. 相似文献
20.
Alexis Pokrovski 《Mathematical Physics, Analysis and Geometry》2007,10(3):197-203
Let be the spectrum of in L
2(ℝ), where q is an even almost-periodic complex-valued function with bounded primitive and derivative. It is known that , where is the spectrum of the unperturbed operator. Suppose that the asymptotic approximation to the first asymptotic correction
is given. We prove the formula that recovers the frequencies and the Fourier coefficients of q in terms of Δμ
n
.
相似文献