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Implementation of quantum partial search with superconducting quantum interference device qudits in cavity QED 下载免费PDF全文
We present a method to implement the quantum partial search of the database separated into any number of blocks with qudits,D-level quantum systems.Compared with the partial search using qubits,our method needs fewer iteration steps and uses the carriers of the information more economically.To illustrate how to realize the idea with concrete physical systems,we propose a scheme to carry out a twelve-dimensional partial search of the database partitioned into three blocks with superconducting quantum interference devices(SQUIDs)in cavity QED.Through the appropriate modulation of the amplitudes of the microwave pulses,the scheme can overcome the non-identity of the cavity–SQUID coupling strengths due to the parameter variations resulting from the fabrication processes.Numerical simulation under the influence of the cavity and SQUID decays shows that the scheme could be achieved efficiently within current state-of-the-art technology. 相似文献
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光的聚束效应的发现是量子光学的重要里程碑.对其进行合理解释的努力,促进了量子光学理论与技术的大发展,使量子光学迅速发展和完善起来.现在一般认为,光场二阶相干所体现的聚束效应的物理本质是双光子干涉.本文发现,在高阶相干中有类似的广义聚束效应,这种广义聚束效应也可以用光子相长干涉解释.而且在一些典型的光路中,Ⅳ个光子参与的干涉,可以使这种广义聚束效应的增强因子达到N!. 相似文献
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We present a scheme for probabilistic remote preparation of an entangled two-qubit state with three parties from a sender to either of two receivers. The quantum channel is composed of a paxtially entangled two-qubit state and a partially entangled three-qubit state. We calculate the successful total probabilities of the scheme in general and particular cases, respectively. We also calculate total classical communication cost in a general case and two particular cases, respectively. 相似文献
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讨论了量子Zeno效应中测量的特点,指出这种测量只是使系统塌缩到原态的一种操作;通过用控制非门的偶数次操作,提出了一种理论上更简单、更易实现的二位防错方案。 相似文献
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We experimentally demonstrate the quantum anti-Zeno effect in a two-level system based on a single trapped ion ~(40)Ca~+. In the large detuning regime, we show that the transfer from the ground state to the excited state can be remarkably enhanced by the inserted projection measurements. The inserted measurements in our experiment are realized by the electron shelving technique. Compared to the ideal projection measurement, which makes the quantum state collapse instantaneously, a practical electron shelving process needs a finite time duration. The minimum time for this collapse process is shown to be inversely proportional to the square of the coupling strength between the measurement laser and the system. 相似文献
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Calculating the spatial structures of ion crystals is important in ion-trapped quantum computation. Here we demonstrate that the simulated annealing method is a powerful tool to evaluate the structures of ion crystals. By calculating equilibrium positions of 10 ions under harmonic potential and those of 120 ions under anharmonic potential, both with the standard procedure and simulated annealing method, we find that the standard procedure to evaluate spatial structures is complicated and may be inefficient in some cases, and that the simulated annealing method is more favorable. 相似文献
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We study the dynamics of the multipartite systems nonresonantly interacting with electromagnetic fields, focusing on the large detuning limit for the effective Hamiltonian. Due to the many-particle interference effects, the more rigorous large detuning condition for neglecting the rapidly oscillating terms for the effective Hamiltonian should be N 1/2 g, instead of g usually used in the literature even in the case of multipartite systems, with N the number of microparticles involved, g the coupling strength, the detuning. This result is significant since merely the satisfaction of the original condition will result in the invalidity of the effective Hamiltonian and the errors of the parameters associated with the detuning in the multipartite case. 相似文献
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The achievable precision of parameter estimation plays a significant role in evaluating a strategy of metrology.In practice,one may employ approximations in a theoretical model development for simplicity,which,however,will cause systematic error and lead to a loss of precision.We derive the error of maximum likelihood estimation in the weak-value amplification technique where the linear approximation of the coupling parameter is used.We show that this error is positively related to the coupling ... 相似文献