共查询到20条相似文献,搜索用时 0 毫秒
1.
We study the question of converting initially Gaussian states into non-Gaussian ones by two- and three-photon subtraction to improve non-classical properties of the conditional optical fields. We show the photon subtraction may effectively generate non-Gaussian states only in case of small values of the mean values of the position and momentum operators. In particular, the photon-subtracted state can be made arbitrary close to Gaussian state in limiting case of large initial amplitude of displacement. Use of initial displacement in input Gaussian states opens wider prospects to manipulate them. In particular, realization of probabilistic Hadamard gate with input Gaussian states is discussed where photon subtraction is motive force able unevenly to increase measure of non-classicality of the output state. Subtraction of larger number of photons enables to increase fidelity and non-classical measure of the conditional states. 相似文献
2.
Multi-level (ML) quantum logic can potentially reduce the number of inputs/outputs or quantum cells in a quantum circuit which
is a limitation in current quantum technology. In this paper we propose theorems about ML-quantum and reversible logic circuits.
New efficient implementations for some basic controlled ML-quantum logic gates, such as three-qudit controlled NOT, Cycle,
and Self Shift gates are proposed. We also propose lemmas about r-level quantum arrays and the number of required gates for an arbitrary n-qudit ML gate. An equivalent definition of quantum cost (QC) of binary quantum gates for ML-quantum gates is introduced and
QC of controlled quantum gates is calculated. 相似文献
3.
主要研究参数化的广义量子通用相位门,给出了单比特量子门、双比特量子门以及三比特量子门的参数化构造。证明参数化的广义量子门和M.Nielsen给出的广义量子门是等价的。举例说明了参数化的广义量子通用门在量子计算中的作用。 相似文献
4.
Quantum teleportation is a computational primitive that allows non-local quantum communication and quantum computation. In
this work, we present two schemes for quantum gate teleportation. The first scheme shows under what conditions an n-qudit gate can be teleported using a generalization of Gottesman-Chuang procedure [Nature 402, 390 (1999)]. The second scheme
shows that quantum gate teleportation can be transformed in the teleportation of a single-qudit. 相似文献
5.
Shi Hu Wen-Xue Cui Qi Guo Hong-Fu Wang Ai-Dong Zhu Shou Zhang 《Quantum Information Processing》2016,15(9):3651-3661
Non-adiabatic holonomic quantum gate in decoherence-free subspaces is of greatly practical importance due to its built-in fault tolerance, coherence stabilization virtues, and short run-time. Here, we propose some compact schemes to implement two- and three-qubit controlled unitary quantum gates and Fredkin gate. For the controlled unitary quantum gates, the unitary operator acting on the target qubit is an arbitrary single-qubit gate operation. The controlled quantum gates can be directly implemented by utilizing non-adiabatic holonomy in decoherence-free subspaces and the required resource for the decoherence-free subspace encoding is minimal by using only two neighboring physical qubits undergoing collective dephasing to encode a logical qubit. 相似文献
6.
We show a new proposal for implementing one-qubit quantum gates in a solid associated with the presence of topological defects. We discuss a new way of obtaining quantum holonomies for a spin-half particle, and the implementation of a set of one-qubit quantum gates based on the topological phases provided by the presence of a defect in a crystalline solid. 相似文献
7.
Quantum logic operations can be implemented using nonlinear phase shifts (the Kerr effect) or the quantum Zeno effect based on strong two-photon absorption. Both approaches utilize three-level atoms, where the upper level is tuned on resonance for the Zeno gates and off-resonance for the nonlinear phase gates. The performance of nonlinear phase gates and Zeno gates are compared under conditions where the parameters of the resonant cavities and three-level atoms are the same in both cases. It is found that the expected performance is comparable for the two approaches despite the fundamental differences between the Zeno and Kerr effects. 相似文献
8.
P. K. Vishnu Dintomon Joy Bikash K. Behera Prasanta K. Panigrahi 《Quantum Information Processing》2018,17(10):274
Local implementation of non-local quantum gates is necessary in a distributed quantum computer. Here, we demonstrate the non-local implementation of controlled-unitary quantum gates proposed by Eisert et al. (Phys Rev A 62:052317, 2000) using the five-qubit IBM quantum computer. We verify the fidelity and accuracy of the implementation through the techniques of quantum state and process tomographies. 相似文献
9.
Long range Rydberg blockade interactions have the potential for efficient implementation of quantum gates between multiple
atoms. Here we present and analyze a protocol for implementation of a k-atom controlled NOT (C
k
NOT) neutral atom gate. This gate can be implemented using sequential or simultaneous addressing of the control atoms which
requires only 2k + 3 or 5 Rydberg π pulses respectively. A detailed error analysis relevant for implementations based on alkali atom Rydberg states is provided
which shows that gate errors less than 10% are possible for k = 35. 相似文献
10.
Azmi Ali Altintas Fatih Ozaydin Can Yesilyurt Sinan Bugu Metin Arik 《Quantum Information Processing》2014,13(4):1035-1044
We study two-level q-deformed angular momentum states, and using q-deformed harmonic oscillators, we provide a framework for constructing qubits and quantum gates. We also present the construction of some basic one-qubit and two-qubit quantum logic gates. 相似文献
11.
In many physical systems, when implementing quantum gate operations unavoidable global and relative phases occur as by-products due to the internal structure of the governing Hamiltonian. To correct, additional phase rotation gates are used, which increases the computational overhead. Here, we show how these phase by-products can actually be used to our advantage by using them to implement universal quantum computing between qubits not directly coupled to each other. The gate operations, CNOT, Toffoli, and swap gates, require much less computational overhead than present schemes, and are achieved with fidelity greater than 99%. We then present a linear nearest-neighbor architecture that takes full advantage of the phase by-products, and we show how to implement gates from a universal set efficiently in this layout. In this scheme gate operations are realized by only varying a single control parameter per data qubit, and the ability to tune couplings is not required. 相似文献
12.
为加快量子遗传算法的参数更新速度,简化遗传操作步骤,提出了一种基于通用量子门的量子遗传算法(Quantum Genetic Algorithm with Universal Quantum Gate,UQGA)。该方法以通用量子门为逻辑计算单位,对染色体进行遗传操作。利用Hadamard门进行基础变换;通用量子门通过新的旋转角度函数,对各个基因位进行选择、变异操作;通过求解适应度函数,得到全局最优解;同时,算法经数学证明是收敛的。该算法应用到函数极值搜索和Iris数据集特征选择中。实验结果表明,UQGA具有较好的全局搜索和特征选择性能,尤其是在收敛速度、运算时间和分类准确率方面明显优于普通量子遗传算法和普通遗传算法。 相似文献
13.
Amit Devra Prithviraj Prabhu Harpreet Singh Arvind Kavita Dorai 《Quantum Information Processing》2018,17(3):67
We have designed efficient quantum circuits for the three-qubit Toffoli (controlled–controlled-NOT) and the Fredkin (controlled-SWAP) gate, optimized via genetic programming methods. The gates thus obtained were experimentally implemented on a three-qubit NMR quantum information processor, with a high fidelity. Toffoli and Fredkin gates in conjunction with the single-qubit Hadamard gates form a universal gate set for quantum computing and are an essential component of several quantum algorithms. Genetic algorithms are stochastic search algorithms based on the logic of natural selection and biological genetics and have been widely used for quantum information processing applications. We devised a new selection mechanism within the genetic algorithm framework to select individuals from a population. We call this mechanism the “Luck-Choose” mechanism and were able to achieve faster convergence to a solution using this mechanism, as compared to existing selection mechanisms. The optimization was performed under the constraint that the experimentally implemented pulses are of short duration and can be implemented with high fidelity. We demonstrate the advantage of our pulse sequences by comparing our results with existing experimental schemes and other numerical optimization methods. 相似文献
14.
15.
We demonstrate a fashion of quantum channel combining and splitting, called polar quantum channel coding, to generate a quantum bit (qubit) sequence that achieves the symmetric capacity for any given binary input discrete quantum channels. The present capacity is achievable subject to input of arbitrary qubits with equal probability. The polarizing quantum channels can be well-conditioned for quantum error-correction coding, which transmits partially quantum data through some channels at rate one with the symmetric capacity near one but at rate zero through others. 相似文献
16.
《Graphical Models》2012,74(6):326-334
Using the homogeneous version of the quantum blossom, we derive formulas and algorithms for the quantum derivatives of quantum Bernstein bases and quantum Bézier curves. 相似文献
17.
In this paper we study small depth circuits that contain threshold gates (with or without weights) and parity gates. All circuits we consider are of polynomial size. We prove several results which complete the work on characterizing possible inclusions between many classes defined by small depth circuits. These results are the following:
相似文献
1. | A single threshold gate with weights cannot in general be replaced by a polynomial fan-in unweighted threshold gate of parity gates. |
2. | On the other hand it can be replaced by a depth 2 unweighted threshold circuit of polynomial size. An extension of this construction is used to prove that whatever can be computed by a depthd polynomial size threshold circuit with weights can be computed by a depthd+1 polynomial size unweighted threshold circuit, whered is an arbitrary fixed integer. |
3. | A polynomial fan-in threshold gate (with weights) of parity gates cannot in general be replaced by a depth 2 unweighted threshold circuit of polynomial size. |
18.
Jino Heo Chang-Ho Hong Hyung-Jin Yang Jong-Phil Hong Seong-Gon Choi 《Quantum Information Processing》2017,16(4):110
We demonstrate the advantages of an optical parity gate using weak cross-Kerr nonlinearities (XKNLs), quantum bus (qubus) beams, and photon number resolving (PNR) measurement through our analysis, utilizing a master equation under the decoherence effect (occurred the dephasing and photon loss). To generate Bell states, parity gates based on quantum non-demolition measurement using XKNL are extensively employed in quantum information processing. When designing a parity gate via XKNL, the parity gate can be diversely constructed according to the measurement strategies. In practice, the interactions of XKNLs in optical fiber are inevitable under the decoherence effect. Thus, by our analysis of the decoherence effect, we show that the designed parity gate employing homodyne measurement would not be expected to provide reliable quantum operation. Furthermore, compared with a parity gate using a displacement operator and PNR measurement, we conclude there is experimental benefit from implementation of a parity gate via qubus beams and PNR measurement under the decoherence effect. 相似文献
19.
20.
DWT比DFT在子信道间有更高的频谱约束力,可以去除COFDM(编码正交频分复用)系统中必须的CP(循环前缀),从而提高带宽利用率。对不同小波下CWOFDM(编码小波正交频分复用)系统在无线信道下的传输性能进行仿真。结果表明,CWOFDM系统抗噪声和多径衰落性能优于COFDM,而且小波的滤波器长度和分解层数都会影响CWOFDM系统抗噪声和多径衰落的性能。 相似文献