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We analyze the quantum walk in higher spatial dimensions and compare classical and quantum spreading as a function of time. Tensor products of Hadamard transformations and the discrete Fourier transform arise as natural extensions of the…

Quantum Physics · Physics 2007-05-23 Troy D. Mackay , Stephen D. Bartlett , Leigh T. Stephenson , Barry C. Sanders

Quantum random walks are shown to have non-intuitive dynamics, which makes them an attractive area of study for devising quantum algorithms for well-known classical problems as well as those arising in the field of quantum computing. In…

Quantum Physics · Physics 2007-12-11 K. Manouchehri , J. B. Wang

A quantum walk describes the discrete unitary evolution of a quantum particle on a discrete graph. Some quantum walks, referred to as the Weyl and Dirac quantum walks, provide a description of the free evolution of relativistic quantum…

Quantum Physics · Physics 2020-09-08 Luca Apadula , Alessandro Bisio , Giacomo Mauro D'Ariano , Paolo Perinotti

The theory of random walks on finite graphs is well developed with numerous applications. In quantum walks, the propagation is governed by quantum mechanical rules; generalizing random walks to the quantum setting. They have been…

Quantum Physics · Physics 2022-05-10 Avah Banerjee

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

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 propose a scheme for the realization of a quantum walker and a quantum simulator for the Dirac equation with ultracold spinor atoms in driven optical lattices. A precise control of the dynamics of the atomic matter wave can be realized…

Quantum Physics · Physics 2011-04-20 D. Witthaut

We implement the discrete-time quantum walk model using the continuous-time evolution of the Hamiltonian that includes both the shift and the coin generators. Based on the Trotter-Suzuki first-order approximation, we consider an…

Quantum Physics · Physics 2022-03-03 Jalil Khatibi Moqadam , Marcos Cesar de Oliveira

We show that the Dirac quantum cellular automaton [Ann. Phys. 354 (2015) 244] shares many properties in common with the discrete-time quantum walk. These similarities can be exploited to study the automaton as a unitary process that takes…

Quantum Physics · Physics 2016-01-26 A. Pérez

Quantum walks function as essential means to implement quantum simulators, allowing one to study complex and often directly inaccessible quantum processes in controllable systems. In this contribution, the notion of a driven Gaussian…

Representing massless Dirac fermions on a spatial lattice poses a potential challenge known as the Fermion Doubling problem. Addition of a quadratic term to the Dirac Hamiltonian circumvents this problem. We show that the modified…

Mesoscale and Nanoscale Physics · Physics 2015-09-15 K. M. Masum Habib , Redwan N. Sajjad , Avik W. Ghosh

Quantum walk (QW) is the quantum analog of the random walk. QW is an integral part of the development of numerous quantum algorithms. Hence, an in-depth understanding of QW helps us to grasp the quantum algorithms. We revisit the…

Quantum Physics · Physics 2021-02-16 Mahesh N. Jayakody , Chandrakala Meena , Priodyuti Pradhan

Discrete quantum walks are dynamical protocols for controlling a single quantum particle. Despite of its simplicity, quantum walks display rich topological phenomena and provide one of the simplest systems to study and understand…

Quantum Physics · Physics 2011-12-09 Takuya Kitagawa

We introduce quantum walks with a time-dependent coin, and show how they include, as a particular case, the generalized quantum walk recently studied by Wojcik et al. {[}Phys. Rev. Lett. \textbf{93}, 180601(2004){]} which exhibits…

Quantum Physics · Physics 2009-11-11 M. C. Banuls , C. Navarrete , A. Perez , Eugenio Roldan , J. C. Soriano

Discrete time quantum walks (DTQWs) are nontrivial generalizations of random walks with a broad scope of applications. In particular, they can be used as computational primitives, and they are suitable tools for simulating other quantum…

Quantum Physics · Physics 2015-02-13 Bálint Kollár , Tamás Kiss , Igor Jex

Quantum walks are referred to as quantum analogs to random walks in mathematics. They have been studied as quantum algorithms in quantum information for quantum computers. There are two types of quantum walks. One is the discrete-time…

Quantum Physics · Physics 2024-06-26 Takuya Machida

We show that a large class of 2-adic Schr\"odinger equations is the scaling limit of certain continuous-time quantum Markov chains (CTQMCs). Practically, a discretization of such an equation gives a CTQMC. As a practical result, we…

Quantum Physics · Physics 2025-06-27 W. A. Zúñiga-Galindo

Quantum walks constitute important tools in different applications, especially in quantum algorithms. To a great extent their usefulness is due to unusual diffusive features, allowing much faster spreading than their classical counterparts.…

Quantum Physics · Physics 2012-10-09 F. M. Andrade , M. G. E. da Luz

We provide first evidence that under certain conditions, 1/2-spin fermions may naturally behave like a Grover search, looking for topological defects in a material. The theoretical framework is that of discrete-time quantum walks (QW), i.e.…

Quantum Physics · Physics 2020-05-13 Mathieu Roget , Stéphane Guillet , Pablo Arrighi , Giuseppe Di Molfetta

We present a recent work on the Dirac equation in a curved spacetime. In addition to the standard equation, two alternative versions are considered, derived from wave mechanics, and based on the tensor representation of the Dirac field. The…

General Relativity and Quantum Cosmology · Physics 2008-10-06 Mayeul Arminjon , Frank Reifler