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We address the question of symmetries of an important type of quantum walks. We introduce all the necessary definitions and provide a rigorous formulation of the problem. Using a thorough analysis, we reach the complete answer by presenting…

Quantum Physics · Physics 2012-11-02 Václav Potoček

Quantum walks have been employed widely to develop new tools for quantum information processing recently. A natural quantum walk dynamics of interacting particles can be used to implement efficiently the universal quantum computation. In…

Quantum Physics · Physics 2016-10-04 Alexey A. Melnikov , Leonid E. Fedichkin

We address the problem of the construction of quantum walks on Cayley graphs. Our main motivation is the relationship between quantum algorithms and quantum walks. In particular, we discuss the choice of the dimension of the local Hilbert…

Quantum Physics · Physics 2014-09-25 O. Lopez Acevedo , T. Gobron

We study the transition matrix of a quantum walk on strongly regular graphs. It is proposed by Emms, Hancock, Severini and Wilson in 2006, that the spectrum of $S^+(U^3)$, a matrix based on the amplitudes of walks in the quantum walk,…

Combinatorics · Mathematics 2011-07-28 Chris Godsil , Krystal Guo

We define and analyze random quantum walks on homogeneous trees of degree $q\geq 3$. Such walks describe the discrete time evolution of a quantum particle with internal degree of freedom in $\C^q$ hopping on the neighboring sites of the…

Mathematical Physics · Physics 2014-07-08 Eman Hamza , Alain Joye

Quantum walks are at the heart of modern quantum technologies. They allow to deal with quantum transport phenomena and are an advanced tool for constructing novel quantum algorithms. Quantum walks on graphs are fundamentally different from…

Quantum Physics · Physics 2019-12-18 Alexey A. Melnikov , Leonid E. Fedichkin , Alexander Alodjants

Quantum walks are standard tools for searching graphs for marked vertices, and they often yield quadratic speedups over a classical random walk's hitting time. In some exceptional cases, however, the system only evolves by sign flips,…

Quantum Physics · Physics 2017-05-05 Thomas G. Wong , Raqueline A. M. Santos

In this paper, we investigate the simulation of continuous-time quantum walks on specific classes of graphs, for which it is possible to fast-forward the time-evolution operator to achieve constant-time simulation complexity and to perform…

Quantum Physics · Physics 2017-02-01 T. Loke , J. B. Wang

The study of quantum evolution on graphs for diversified topologies is beneficial to modeling various realistic systems. A systematic method, the dimerized decomposition, is proposed to analyze the dynamics on an arbitrary network. By…

Quantum Physics · Physics 2020-03-04 He Feng , Tian-Min Yan , Y. H. Jiang

The conventional spectral mapping theorem for quantum walks can only be applied for walks employing a shift operator whose square is the identity. This theorem gives most of the eigenvalues of the time evolution $U$ by lifting the…

Quantum Physics · Physics 2021-03-10 Sho Kubota , Kei Saito , Yusuke Yoshie

Discrete quantum walks are periodically driven systems with discrete time evolution. In contrast to ordinary Floquet systems, no microscopic Hamiltonian exists, and the one-period time evolution is given directly by a series of unitary…

Mesoscale and Nanoscale Physics · Physics 2025-01-10 Ken Mochizuki , Takumi Bessho , Masatoshi Sato , Hideaki Obuse

We consider a position-dependent quantum walk on ${\bf Z}$. In particular, we derive a detection method for edge defects by embedded eigenvalues of its time evolution operator. In the present paper, the set of edge defects is that of points…

Spectral Theory · Mathematics 2024-03-26 Hisashi Morioka , Etsuo Segawa

Constructing a discrete model like a cellular automaton is a powerful method for understanding various dynamical systems. However, the relationship between the discrete model and its continuous analogue is, in general, nontrivial. As a…

Quantum Physics · Physics 2014-03-24 Yutaka Shikano , Tatsuaki Wada , Junsei Horikawa

Recently, quantized versions of random walks have been explored as effective elements for quantum algorithms. In the simplest case of one dimension, the theory has remained divided into the discrete-time quantum walk and the continuous-time…

Quantum Physics · Physics 2009-11-13 Frederick W. Strauch

Quantum walks on graphs are fundamental to quantum computing and have led to many interesting open problems in algebraic graph theory. This review article highlights three key classes of open problems in this domain; perfect state transfer,…

Combinatorics · Mathematics 2024-04-04 Gabriel Coutinho , Krystal Guo

In this note, we discuss a general definition of quantum random walks on graphs and illustrate with a simple graph the possibility of very different behavior between a classical random walk and its quantum analogue. In this graph,…

Quantum Physics · Physics 2007-05-23 Andrew M. Childs , Edward Farhi , Sam Gutmann

We describe the time evolution of quantum systems in a classical background space-time by means of a covariant derivative in an infinite dimensional vector bundle. The corresponding parallel transport operator along a timelike curve $\cC$…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Dirk Graudenz

Quantum walks on graphs have shown prioritized benefits and applications in wide areas. In some scenarios, however, it may be more natural and accurate to mandate high-order relationships for hypergraphs, due to the density of information…

Quantum Physics · Physics 2017-09-26 Ying Liu , Jiabin Yuan , Bojia Duan , Dan Li

The discrete-time quantum walk (QW) has been extensively and intensively investigated for the last decade, whose coin operator is defined by a unitary matrix. We extend the QW to a walk determined by a unitary matrix whose component is…

Quantum Physics · Physics 2015-05-05 Norio Konno

The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise quantum walks have shown much potential as a frame- work for developing new quantum algorithms.…