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We study a transport phenomenon in certain coined quantum walks where a subspace of states localized at a vertex gets transferred to another vertex. We first develop characterizations for perfect and pretty good subspace state transfer…

Combinatorics · Mathematics 2025-12-01 Yichi Xu , Hanmeng Zhan

Previously it was shown that (almost) perfect state transfer can be achieved on the complete bipartite graph by a discrete-time coined quantum walk based algorithm when both the sender and receiver vertices are in the same partition of the…

Quantum Physics · Physics 2022-03-09 R. A. M. Santos

We generalize the discrete quantum walk on the line using a time dependent unitary coin operator. We find an analytical relation between the long-time behaviors of the standard deviation and the coin operator. Selecting the coin time…

Quantum Physics · Physics 2015-05-13 Alejandro Romanelli

We clarify that coined quantum walk is determined by only the choice of local quantum coins. To do so, we characterize coined quantum walks on graph by disjoint Euler circles with respect to symmetric arcs. In this paper, we introduce a new…

Mathematical Physics · Physics 2014-05-08 Yusuke Higuchi , Norio Konno , Iwao Sato , Etsuo Segawa

Quantum walks obey unitary dynamics: they form closed quantum systems. The system becomes open if the walk suffers from imperfections represented as missing links on the underlying basic graph structure, described by dynamical percolation.…

Quantum Physics · Physics 2012-07-11 Bálint Kollár , Tamás Kiss , Jaroslav Novotný , Igor Jex

A continuous-time quantum walk is modelled using a graph. In this short paper, we provide lower bounds on the size of a graph that would allow for some quantum phenomena to occur. Among other things, we show that, in the adjacency matrix…

Combinatorics · Mathematics 2018-05-23 Gabriel Coutinho

We investigate quantum walks in multiple dimensions with different quantum coins. We augment the model by assuming that at each step the amplitudes of the coin state are multiplied by random phases. This model enables us to study in detail…

Quantum Physics · Physics 2009-11-13 Jozef Kosik , Vladimir Buzek , Mark Hillery

We introduce a variation of the discrete time quantum walk, the nonreversal quantum walk, which does not step back onto a position which it has just occupied. This allows us to simulate a dimer and we achieve it by introducing a new type of…

Quantum Physics · Physics 2014-06-27 T. J. Proctor , K. E. Barr , B. Hanson , S. Martiel , V. Pavlovic , A. Bullivant , V. M. Kendon

This paper discusses continuous-time quantum walks and asymptotic state transfer in graphs with an involution. By providing quantitative bounds on the eigenvectors of the Hamiltonian, it provides an approach to achieving high-fidelity state…

Quantum Physics · Physics 2023-10-16 Gabor Lippner , Yujia Shi

We propose a variation of the quantum walk on a circle in phase space by conjoining the Hadamard coin flip with simultaneous displacement of the walker's location in phase space and show that this generalization is a proper quantum walk…

Quantum Physics · Physics 2008-05-26 Peng Xue , Barry C. Sanders

Quantum walks, both discrete (coined) and continuous time, on a general graph of N vertices with undirected edges are reviewed in some detail. The resource requirements for implementing a quantum walk as a program on a quantum computer are…

Quantum Physics · Physics 2007-05-23 Viv Kendon

Quantum and random walks have been shown to be equivalent in the following sense: a time-dependent random walk can be constructed such that its vertex distribution at all time instants is identical to the vertex distribution of any…

Quantum Physics · Physics 2023-06-13 Matheus G. Andrade , Franklin de Lima Marquezino , Daniel R. Figueiredo

Quantum walks are the quantum-mechanical analog of random walks, in which a quantum `walker' evolves between initial and final states by traversing the edges of a graph, either in discrete steps from node to node or via continuous evolution…

Quantum Physics · Physics 2015-05-19 Michael S. Underwood , David L. Feder

Quantum walks have by now been realized in a large variety of different physical settings. In some of these, particularly with trapped ions, the walk is implemented in phase space, where the corresponding position states are not orthogonal.…

Quantum Physics · Physics 2014-04-02 R. Matjeschk , A. Ahlbrecht , M. Enderlein , Ch. Cedzich , A. H. Werner , M. Keyl , T. Schaetz , R. F. Werner

We propose a scheme for perfect transfer of an unknown qubit state via the discrete-time quantum walk on a line or a circle. For this purpose, we introduce an additional coin operator which is applied at the end of the walk. This operator…

Quantum Physics · Physics 2015-05-28 İ. Yalçınkaya , Z. Gedik

Quantum random walks have been much studied recently, largely due to their highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum random walk on the line: the use of multiple…

Quantum Physics · Physics 2009-11-07 Todd A. Brun , Hilary A. Carteret , Andris Ambainis

We study a natural construction of a general class of inhomogeneous quantum walks (namely walks whose transition probabilities depend on position). Within the class we analyze walks that are periodic in position and show that, depending on…

Quantum Physics · Physics 2013-05-29 Noah Linden , James Sharam

Quantum state transfer between different sites is a significant problem for quantum networks and quantum computers. By selecting quantum walks with two coins as the basic model and two coin spaces as the communication carriers, we…

Quantum Physics · Physics 2019-12-13 Yun Shang , Meng Li

We present a generalized definition of discrete-time quantum walks convenient for capturing a rather broad spectrum of walker's behavior on arbitrary graphs. It includes and covers both: the geometry of possible walker's positions with…

Quantum Physics · Physics 2019-05-08 Jan Mareš , Jaroslav Novotný , Igor Jex

We introduce and analyze a one-dimensional quantum walk with two time-independent rotations on the coin. We study the influence on the property of quantum walk due to the second rotation on the coin. Based on the asymptotic solution in the…

Quantum Physics · Physics 2014-06-13 Peng Xue , Rong Zhang , Hao Qin , Xiang Zhan , Zhihao Bian , Jian Li