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A discrete time quantum walk is known to be the single-particle sector of a quantum cellular automaton. Searching in this mathematical framework has interested the community since a long time. However, most results consider spatial search…

Quantum Physics · Physics 2023-12-27 Mathieu Roget , Giuseppe Di Molfetta

We construct a new type of quantum walks on simplicial complexes as a natural extension of the well-known Szegedy walk on graphs. One can numerically observe that our proposing quantum walks possess linear spreading and localization as in…

Mathematical Physics · Physics 2015-08-05 Kaname Matsue , Osamu Ogurisu , Etsuo Segawa

Quantum walks, both discrete (coined) and continuous time, form the basis of several quantum algorithms and have been used to model processes such as transport in spin chains and quantum chemistry. The enhanced spreading and mixing…

Quantum Physics · Physics 2010-12-10 Godfrey Leung , Paul Knott , Joe Bailey , Viv Kendon

In this paper, we introduce a multidimensional generalization of Kitagawa's split-step discrete-time quantum walk, study the spectrum of its evolution operator for the case of one defect coins, and prove localization of the walk. Using a…

Mathematical Physics · Physics 2017-03-16 Toru Fuda , Daiju Funakawa , Akito Suzuki

We formulate three current models of discrete-time quantum walks in a combinatorial way. These walks are shown to be closely related to rotation systems and 1-factorizations of graphs. For two of the models, we compute the traces and total…

Combinatorics · Mathematics 2019-05-17 Chris Godsil , Hanmeng Zhan

Quantum counting is a key quantum algorithm that aims to determine the number of marked elements in a database. This algorithm is based on the quantum phase estimation algorithm and uses the evolution operator of Grover's algorithm because…

Quantum Physics · Physics 2023-12-11 Gustavo A. Bezerra , Raqueline A. M. Santos , Renato Portugal

We study the average probability that a discrete-time quantum walk finds a marked vertex on a graph. We first show that, for a regular graph, the spectrum of the transition matrix is determined by the weighted adjacency matrix of an…

Combinatorics · Mathematics 2021-08-24 Hanmeng Zhan

We present analytical treatment of quantum walks on a cycle graph. The investigation is based on a realistic physical model of the graph in which decoherence is induced by continuous monitoring of each graph vertex with nearby quantum point…

Quantum Physics · Physics 2007-05-23 Dmitry Solenov , Leonid Fedichkin

The role of classical noise in quantum walks (QW) on integers is investigated in the form of discrete dichotomic random variable affecting its reshuffling matrix parametrized as a SU2)/U(1) coset element. Analysis in terms of quantum…

Quantum Physics · Physics 2015-06-05 D. Ellinas , A. J. Bracken , I. Smyrnakis

We study a particular class of trace-preserving completely positive maps, called PQ-channels, for which classical and quantum evolutions are isolated in a certain sense. By combining open quantum random walks with a notion of recurrence, we…

Mathematical Physics · Physics 2015-06-26 Carlos F. Lardizabal , Rafael R. Souza

We consider a discrete-time 2-state quantum walk on the line. The state of the quantum walker evolves according to a rule which is determined by a coin-flip operator and a position-shift operator. In this paper we take a 3-periodic time…

Quantum Physics · Physics 2015-06-03 F. Alberto Grünbaum , Takuya Machida

In this Chapter, we present some interesting properties of quantum walks on the line. We concentrate our attention in the emergence of invariance and provide some insights into the ultimate origin of the observed behavior. In the first part…

Quantum Physics · Physics 2016-09-02 Miquel Montero

We formulate a framework for discrete-time quantum walks, motivated by classical random walks with memory. We present a specific representation of the classical walk with memory 2 on which this is based. The framework has no need for coin…

We demonstrate that continuous time quantum walks on several types of branching graphs, including graphs with loops, are identical to quantum walks on simpler linear chain graphs. We also show graph types for which such equivalence does not…

Quantum Physics · Physics 2016-02-09 Thomas Cavin , Dmitry Solenov

Consider a graph whose vertices are populated by identical objects, together with an algorithm for the time-evolution of the number of objects placed at each of the vertices. The discrete dynamics of these objects can be observed and…

Quantum Physics · Physics 2024-02-13 Emil Prodan

We survey the equations of continuous-time quantum walks on simple one-dimensional lattices, which include the finite and infinite lines and the finite cycle, and compare them with the classical continuous-time Markov chains. The focus of…

Other Condensed Matter · Physics 2007-05-23 D. ben-Avraham , E. Bollt , C. Tamon

We give a new determinant expression for the characteristic polynomial of the bond scattering matrix of a quantum graph G. Also, we give a decomposition formula for the characteristic polynomial of the bond scattering matrix of a regular…

Mathematical Physics · Physics 2012-11-21 Yusuke Higuchi , Norio Konno , Iwao Sato , Etsuo Segawa

We consider the time-independent scattering theory for time evolution operators of one-dimensional two-state quantum walks. The scattering matrix associated with the position-dependent quantum walk naturally appears in the asymptotic…

Mathematical Physics · Physics 2021-03-23 Takashi Komatsu , Norio Konno , Hisashi Morioka , Etsuo Segawa

In this research article, we design a quantum hash function model from hybrid quantum walks on finite path graph. The hybrid evolution operator consisting of integrated framework of continuous time quantum walks and lackadaisical quantum…

Quantum Physics · Physics 2025-05-22 Rachana Soni , Navneet Pratap Singh , Neelam Choudhary

Among the discrete evolution equations describing a quantum system $\rH_S$ undergoing repeated quantum interactions with a chain of exterior systems, we study and characterize those which are directed by classical random variables in…

Mathematical Physics · Physics 2007-12-21 Stéphane Attal , Ameur Dhahri