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Quantum walks constitute a versatile platform for simulating transport phenomena on discrete graphs including topological material properties while providing a high control over the relevant parameters at the same time. To experimentally…

The continuous-time quantum walk is a particle evolving by Schr\"odinger's equation in discrete space. Encoding the space as a graph of vertices and edges, the Hamiltonian is proportional to the discrete Laplacian. In some physical systems,…

Quantum Physics · Physics 2021-10-26 Thomas G. Wong , Joshua Lockhart

We consider the Grover walk model on a connected finite graph with two infinite length tails and we set an $\ell^\infty$-infinite external source from one of the tails as the initial state. We show that for any connected internal graph, a…

Mathematical Physics · Physics 2020-01-08 Yusuke Higuchi , Etsuo Segawa

Quantum walks on graphs can model physical processes and serve as efficient tools in quantum information theory. Once we admit random variations in the connectivity of the underlying graph, we arrive at the problem of percolation, where the…

Quantum Physics · Physics 2014-02-12 Bálint Kollár , Jaroslav Novotný , Tamás Kiss , Igor Jex

We solve an open problem by constructing quantum walks that not only detect but also find marked vertices in a graph. In the case when the marked set $M$ consists of a single vertex, the number of steps of the quantum walk is quadratically…

Quantum Physics · Physics 2016-03-01 Hari Krovi , Frédéric Magniez , Maris Ozols , Jérémie Roland

We analyze a continuous-time quantum walk on a chimera graph, which is a graph of choice for designing quantum annealers, and we discover beautiful quantum-walk features such as localization that starkly distinguishes classical from quantum…

Quantum Physics · Physics 2018-03-20 Shu Xu , Xiangxiang Sun , Jizhou Wu , Wei-Wei Zhang , Nigum Arshed , Barry C. Sanders

Quantum walk is one of the main tools for quantum algorithms. Defined by analogy to classical random walk, a quantum walk is a time-homogeneous quantum process on a graph. Both random and quantum walks can be defined either in continuous or…

Quantum Physics · Physics 2010-01-10 Andrew M. Childs

In this paper we study continuous-time quantum walks on Cayley graphs of the symmetric group, and prove various facts concerning such walks that demonstrate significant differences from their classical analogues. In particular, we show that…

Quantum Physics · Physics 2007-05-23 Heath Gerhardt , John Watrous

Berry and Wang [Phys. Rev. A {\bf 83}, 042317 (2011)] show numerically that a discrete-time quantum random walk of two noninteracting particles is able to distinguish some non-isomorphic strongly regular graphs from the same family. Here we…

Quantum Physics · Physics 2013-08-27 Kenneth Rudinger , John King Gamble , Eric Bach , Mark Friesen , Robert Joynt , S. N. Coppersmith

Quantum walks are a well-established model for the study of coherent transport phenomena and provide a universal platform in quantum information theory. Dynamically influencing the walker's evolution gives a high degree of flexibility for…

Given the extensive application of classical random walks to classical algorithms in a variety of fields, their quantum analogue in quantum walks is expected to provide a fruitful source of quantum algorithms. So far, however, such…

Quantum Physics · Physics 2008-03-26 B. L. Douglas , J. B. Wang

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

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

We present a direct and simple method for the computation of the total scattering matrix of an arbitrary finite noncompact connected quantum graph given its metric structure and local scattering data at each vertex. The method is inspired…

Mathematical Physics · Physics 2010-01-06 V. Caudrelier , E. Ragoucy

This tutorial article showcases the many varieties and uses of quantum walks. Discrete time quantum walks are introduced as counterparts of classical random walks. The emphasis is on the connections and differences between the two types of…

Quantum Physics · Physics 2013-05-16 Daniel Reitzner , Daniel Nagaj , Vladimir Buzek

We introduce a simple diagrammatic approach for estimating how a randomly walking quantum particle searches on a graph in continuous-time, which involves sketching small weighted graphs with self-loops and considering degenerate…

Quantum Physics · Physics 2015-06-12 Thomas G. Wong

A quantum walk places a traverser into a superposition of both graph location and traversal "spin." The walk is defined by an initial condition, an evolution determined by a unitary coin/shift-operator, and a measurement based on the…

Quantum Physics · Physics 2015-11-25 Marko A. Rodriguez , Jennifer H. Watkins

A discrete-time quantum walk on a graph is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. Hitting times for discrete quantum walks on graphs give an average time before the walk…

Quantum Physics · Physics 2007-11-13 Hari Krovi

In this paper we study discrete-time quantum walks on Cayley graphs corresponding to Dihedral groups, which are graphs with both directed and undirected edges. We consider the walks with coins that are one-parameter continuous deformation…

Quantum Physics · Physics 2023-09-28 Rohit Sarma Sarkar , Bibhas Adhikari

The Scattering Quantum Random Walk scheme has found success as a basis for search algorithms on highly symmetric graph structures. In this paper we examine its effectiveness at locating a specially marked vertex on square grid graphs,…

Quantum Physics · Physics 2019-01-23 Daniel Koch