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In this paper, we will define a quantum operator that performs the inversion about the mean only on a subspace of the system (Partial Diffusion Operator). This operator is used in a quantum search algorithm that runs in O(sqrt{N/M}) for…

Quantum Physics · Physics 2009-11-10 Ahmed Younes , Jon Rowe , Julian Miller

The essential operations of a quantum computer can be accomplished using solely optical elements, with different polarization or spatial modes representing the individual qubits. We present a simple all-optical implementation of Grover's…

Quantum Physics · Physics 2015-06-26 P. G. Kwiat , J. R. Mitchell , P. D. D. Schwindt , A. G. White

Grover's quantum algorithm for an unstructured search problem and the Count algorithm by Brassard et al. are generalized to the case when the initial state is arbitrarily and maximally entangled. This ansatz might be relevant with quantum…

Quantum Physics · Physics 2007-05-23 A. Carlini , A. Hosoya

Grover's quantum search algorithm is considered as one of the milestone in the field of quantum computing. The algorithm can search for a single match in a database with $N$ records in $O(\sqrt{N})$ assuming that the item must exist in the…

Quantum Physics · Physics 2008-12-01 Ahmed Younes

We use quantum walks to construct a new quantum algorithm for element distinctness and its generalization. For element distinctness (the problem of finding two equal items among N given items), we get an O(N^{2/3}) query quantum algorithm.…

Quantum Physics · Physics 2014-05-01 Andris Ambainis

Solutions of quaternionic quantum mechanics (QQM) are difficult to grasp, even in simple physical situations. In this article, we provide simple and understandable free particle quaternionic solutions, that can be easily compared to complex…

Quantum Physics · Physics 2019-08-28 Sergio Giardino

In the quantum database search problem we are required to search for an item in a database. In this paper, we consider a generalization of this problem, where we are provided d identical copes of a database each with N items which we can…

Quantum Physics · Physics 2007-05-23 Lov K. Grover , Jaikumar Radhakrishnan

Quantum search algorithms are considered in the context of protein sequence comparison in biocomputing. Given a sample protein sequence of length m (i.e m residues), the problem considered is to find an optimal match in a large database…

Quantum Physics · Physics 2009-11-06 Lloyd C. L. Hollenberg

Quantum computation has attracted much attention since it was shown by Shor and Grover the possibility to implement quantum algorithms able to realize, respectively, factoring and searching in a faster way than any other known classical…

Quantum Physics · Physics 2007-05-23 Rubens Viana Ramos , Paulo Benicio de Sousa , David Sena Oliveira

Recent decades, the emergence of numerous novel algorithms makes it a gimmick to propose an intelligent optimization system based on metaphor, and hinders researchers from exploring the essence of search behavior in algorithms. However, it…

Neural and Evolutionary Computing · Computer Science 2022-04-18 Peng Wang , Gang Xin , Fang Wang

Searching and sorting used as a subroutine in many important algorithms. Quantum algorithm can find a target item in a database faster than any classical algorithm. One can trade accuracy for speed and find a part of the database (a block)…

Quantum Physics · Physics 2009-11-13 Vladimir E. Korepin , Brenno C. Vallilo

Consider the unstructured search of an unknown number l of items in a large unsorted database of size N. The multi-object quantum search algorithm consists of two parts. The first part of the algorithm is to generalize Grover's…

Quantum Physics · Physics 2015-06-26 Goong Chen , Zijian Diao

Quantum algorithms for searching one or more marked items on a d-dimensional lattice provide an extension of Grover's search algorithm including a spatial component. We demonstrate that these lattice search algorithms can be viewed in terms…

Quantum Physics · Physics 2015-05-19 Birgit Hein , Gregor Tanner

Quantum computing has emerged as a promising avenue for achieving significant speedup, particularly in large-scale PDE simulations, compared to classical computing. One of the main quantum approaches involves utilizing Hamiltonian…

Quantum Physics · Physics 2024-12-18 Junpeng Hu , Shi Jin , Nana Liu , Lei Zhang

Solving the time-dependent Schr\"odinger equation is an important application area for quantum algorithms. We consider Schr\"odinger's equation in the semi-classical regime. Here the solutions exhibit strong multiple-scale behavior due to a…

Quantum Physics · Physics 2022-06-22 Shi Jin , Xiantao Li , Nana Liu

We study quantum algorithms for spatial search on finite dimensional grids. Patel et al. and Falk have proposed algorithms based on a quantum walk without a coin, with different operators applied at even and odd steps. Until now, such…

Quantum Physics · Physics 2015-10-14 Andris Ambainis , Renato Portugal , Nikolay Nahimov

We study the quantum search algorithm as an open system. More specifically, we analyze the responses of that algorithm to an external monochromatic field, and to the decoherences introduced by the measurement process. We find that the…

Quantum Physics · Physics 2007-05-23 A. Romanelli , A. Auyuanet , R. Donangelo

A generalized quantum search algorithm, where phase inversions for the marked state and the prepared state are replaced by $\pi/2$ phase rotations, is realized in a 2-qubit NMR heteronuclear system. The quantum algorithm searches a marked…

Quantum Physics · Physics 2009-11-06 G. L. Long , H. Y. Yan , Y. S. Li , C. C. Tu , J. X. Tao , H. M. Chen , M. L. Liu , X. Zhang , J. Luo , L. Xiao , X. Z. Zeng

A quantum computer has a clear advantage over a classical computer for exhaustive search. The quantum mechanical algorithm for exhaustive search was originally derived by using subtle properties of a particular quantum mechanical operation…

Quantum Physics · Physics 2009-01-23 Lov K. Grover

Quantum spatial search has been widely studied with most of the study focusing on quantum walk algorithms. We show that quantum walk algorithms are extremely sensitive to systematic errors. We present a recursive algorithm which offers…

Quantum Physics · Physics 2016-02-15 Avatar Tulsi