Shor's factorisation algorithm is a combination of classical pre- and post-processing and a quantum period finding (QPF) subroutine which allows an exponential speed up over classical factoring algorithms. We cons...
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Shor's factorisation algorithm is a combination of classical pre- and post-processing and a quantum period finding (QPF) subroutine which allows an exponential speed up over classical factoring algorithms. We consider the stability of this subroutine when exposed to a discrete error model that acts to perturb the computational trajectory of a quantum computer. Through detailed state vector simulations of an appropriate quantum circuit, we show that the error locations within the circuit itself heavily influences the probability of success of the QPF subroutine. The results also indicate that the naive estimate of required component precision is too conservative.
Pulsed Electron Nuclear DOuble Resonance (pulsed ENDOR) has been studied for realization of quantumalgorithms, emphasizing the implementation of organic molecular entities with an electron spin and a nuclear spin for...
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Pulsed Electron Nuclear DOuble Resonance (pulsed ENDOR) has been studied for realization of quantumalgorithms, emphasizing the implementation of organic molecular entities with an electron spin and a nuclear spin for quantuminformationprocessing. The scheme has been examined in terms of quantuminformationprocessing. Particularly, superdense coding has been implemented from the experimental side and the preliminary results are represented as theoretical expectations.
A growing appreciation among researchers is the use of quadrupolar nuclei with spin > 1/2 as a suitable candidate for. quantuminformationprocessing. Such systems have multiple. qubits per nuclei and large quadrup...
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A growing appreciation among researchers is the use of quadrupolar nuclei with spin > 1/2 as a suitable candidate for. quantuminformationprocessing. Such systems have multiple. qubits per nuclei and large quadrupolar couplings, resulting in well separated lines in the spectrum. Preparation of pseudopure states and implementation of logic gates have been demonstrated in these systems. Two-qubit quantumalgorithms have also been implemented in spin-3/2 systems. In this letter we report implementation of three-qubit Deutsch-Jozsa algorithm [Proc. R. Soc. London, Ser. A 693, 553 (. 1992)] in a spin-7/2 system of Cs-133 nucleus oriented in a liquid crystalline matrix. (c) 2006 American Institute of Physics.
It is well understood that the use of quantum entanglement significantly enhances the computational power of systems. Much of the attention has focused on Bell states and their multipartite generalizations. However, i...
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It is well understood that the use of quantum entanglement significantly enhances the computational power of systems. Much of the attention has focused on Bell states and their multipartite generalizations. However, in the multipartite case it is known that there are several inequivalent classes of states, such as those represented by the W-state and the CHZ-state. Our main contribution is a demonstration of the special computational power of these states in the context of paradigmatic problems from classical distributed computing. Concretely, we show that the W-state is the only pure state that can be used to exactly solve the problem of leader election in anonymous quantum networks. Similarly we show that the GHZ-state is the only one that can be used to solve the problem of distributed consensus when no classical post-processing is considered. These results generalize to a family of W- and GHZ-like states. At the heart of the proofs of these impossibility results lie symmetry arguments.
There has been much recent effort to realize quantum devices in many different physical systems. Among them, nuclear magnetic resonance (NMR) has been the first to demonstrate nontrivial quantumalgorithms with small ...
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There has been much recent effort to realize quantum devices in many different physical systems. Among them, nuclear magnetic resonance (NMR) has been the first to demonstrate nontrivial quantumalgorithms with small numbers of qubits and hence is a prototype for the key ingredients needed to build quantum computers. An important building block in many quantum applications is the scattering circuit, which can be used as a quantum multimeter to perform various quantuminformationprocessing tasks directly without recourse to quantum tomography. We implement in NMR a three-qubit version of the multimeter and also demonstrate a single-qubit fingerprinting.
The last two decades feature an ever-increasing interest in quantuminformationprocessing - generalization of the classical computational models in the view of quantum mechanics (QM). In theory, quantum computational...
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The last two decades feature an ever-increasing interest in quantuminformationprocessing - generalization of the classical computational models in the view of quantum mechanics (QM). In theory, quantum computational devices are capable of solving in polynomial time problems for which only algorithms with exponential time complexity are known. Such enormous advantage explains the global scale of scientific efforts for creating the quantum computer - physical realization of such computational device. While the results of those efforts are still constrained inside the large experimental laboratories, an adequate tool for studying quantumalgorithms will be of great help for educating the next generation of computer scientists - the engineers that will be responsible for operating these devices. The paper describes a quantum computer simulation model that exhibits a certain attractive property - the simulation slowdown does not depend directly on the size of the input data but rather on the complexity of the quantum state, meaning that transformations upon less-entangled data are performed faster. Based on this property the simulation can be spread between the nodes of a grid cluster in a way as to keep the entanglement in each job minimal
A novel algorithm, named quantum-behaved particle swarm optimization (QPSO) proposed by us previously is introduced in the design of twodimensional (2-D) recursive digital filters. The design of the 2-D filters is red...
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A novel algorithm, named quantum-behaved particle swarm optimization (QPSO) proposed by us previously is introduced in the design of twodimensional (2-D) recursive digital filters. The design of the 2-D filters is reduced to a constrained minimization problem that is solved by QPSO, which is a global stochastic searching technique and be able to find out the global optima of the problem more efficiently than original particle swarm optimization (PSO). Experiment results show the superiority of the proposed method by comparing it with those of some previous designs.
A quantum algorithm for character recognition based on quantum superposition and quantum entanglement is proposed. Numerical results show that the probability in the desired state will be almost 1 by iterative quantum...
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A quantum algorithm for character recognition based on quantum superposition and quantum entanglement is proposed. Numerical results show that the probability in the desired state will be almost 1 by iterative quantum correlation and observation
The classical optimal solution of CDMA multi-user detection is consistent with the optimization of a quadratic function, and to find the optimum is a NP hard problem. Reducing the complexity of optimum based on quantu...
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The classical optimal solution of CDMA multi-user detection is consistent with the optimization of a quadratic function, and to find the optimum is a NP hard problem. Reducing the complexity of optimum based on quantum parallel computation is a new trend of multi-user detection techniques. In this paper, we propose a scheme based on Grover's searching algorithm to find the optimum. We give the relationship of bit error rate against signal-to-noise and correlation coefficient by numerical simulation, and simply evaluate the computational complexity of our proposed scheme. The results show that our solution has almost the same performance to the classical optimal one, however, with low complexity
On one hand, image segmentation is a low-level processing task which consists in partitioning an image into homogeneous regions. It can be seen as being a combinatorial optimization problem. In fact, considering the h...
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On one hand, image segmentation is a low-level processing task which consists in partitioning an image into homogeneous regions. It can be seen as being a combinatorial optimization problem. In fact, considering the huge amount of information that an image carries, it is impossible to find the best segmentation. On the other hand, quantum genetic algorithms are characterized by their high diversity, and by a good balance between global and local search. In this paper, we present a quantum genetic algorithm for image segmentation
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