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1.
Measurement-based quantum computation in an optical setup shows great promise towards the implementation oflarge-scale quantum computation. The difficulty of measurement-based quantum computation lies in the preparation ofcluster state. In this paper, we propose the method of generating the large-scale cluster state, which is a platform formeasurement-based quantum computation. In order to achieve more complex quantum circuits, the preparation protocolof N-photon cluster state will be proposed as a generalization of the preparation of four- and five-photon cluster states.Furthermore, our proposal is experimentally feasible. 相似文献
2.
采用Nd0 .7Sr0 .3MnO3/SrTiO3/YBa2 Cu3O7-δ的异质结构 ,研究了自旋极化准粒子的注入效应 .在 5 6 μm宽的YBCO膜条上成功地制备了与超导膜条同样宽度但不同长度的六个注入结区 ,长度L分别为 80 μm ,4 0 μm ,2 0 μm ,10 μm ,5 μm和 2 μm .80nm厚的YBCO薄膜在 16K温度下Jc 为 2× 10 5A/cm2 .Iin=0 .5mA的自旋电流注入下 ,随L从 80 μm逐渐顺次减小时 ,注入效率 η =ΔJc/ΔJin逐渐增大 .而当L≤ 2 0 μm后 ,η不再增加 ,达到几乎相同的值 (～ 6 ) .初步分析认为这与自旋极化准粒子在超导膜内的有效自旋扩散长度有关 .异质结构中YBCO薄膜的超导电性以及注入窗口的尺寸对获得大的自旋注入效率十分重要 . 相似文献
4.
经由偏振无关的光学分束器实现对未知两光子部分纠缠态的纠缠浓缩,包括利用单光子探测器的线性光学浓缩方案,和利用弱交叉Kerr非线性媒质、零拍探测的浓缩方案。两对部分纠缠的光子对中各一个信号光子同时通过偏振无关分束器后,当探测到分束器输出模中各有一个光子时,剩余的两光子将处于最大纠缠态。与以前的浓缩方案相比较,我们的浓缩方案不需要额外的Hadmard门对信号光子施加作用,所需要的光学器件较少,这增加了方案在实验实现上的可行性。 相似文献
5.
We propose a scheme to implement an unconventional geometric phase gate in circuit QED, i.e. two superconducting charge qubits inside a superconducting transmission line resonator. The quantum operation depends only on global geometric features, and thus is insensitive to the state of the cavity mode. 相似文献
6.
在旋波近似下,利用推广的J-C模型,考虑光场的频率随时间按照正弦函数的形式作小量变化,采用数值计算的方法,研究分析二项式光场与二能级原子相互作用时,光场的振幅平方压缩效应。最终的研究结果表明：场频率的变化对光场的振幅平方压缩的深度和周期性都存在影响 相似文献
7.
The entanglement property of two identical atoms,initially entangled in Bell states, coupled to a single-mode cavityis considered. Based on the reduced non-perturbative quantum masterequation method, the entanglement evolution of the two atoms withdecay is investigated beyond the conventional rotating-waveapproximation. We show that the counter-rotating wave terms,usually neglected, have a great influence on the disentanglementbehaviour of the system. The phenomena of entanglement sudden deathand entanglement sudden birth will occur. In addition, we show thatthe entanglement can be strengthened by introducing thedipole--dipole interaction of the two atoms. 相似文献
8.
Quantum superdense coding (QSC) is an example of how entanglementcan be used to minimize the number of carriers of classicalinformation. This paper proposes two schemes for implementing QSC bymeans of cavity assisted interactions with single-photon pulses. Theschemes are insensitive to the cavity decay and the thermal field,thus it might be realizable based on the current cavity QEDtechniques. 相似文献
9.
An experimentally realizable physical scheme for preparing multiqubit cluster states from a large detuned atomcavity interaction is proposed. The scheme is free of any type of measurement and insensitive to the cavity decay, and the cavity field is only virtually excited so that there is no information exchanging between atom and cavity. The time required for the gate operations is very short, which is important for decoherence. We also discuss the experimental feasibility of our scheme. 相似文献
10.
在旋波近似下,利用推广的J-C模型,考虑光场的频率随时间按照正弦函数的形式作小量变化,采用数值计算的方法,研究分析二项式光场与二能级原子相互作用时,光场的振幅平方压缩效应.最终的研究结果表明:场频率的变化对光场的振幅平方压缩的深度和周期性都存在影响. 相似文献