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We consider the problem of searching a general $d$-dimensional lattice of $N$ vertices for a single marked item using a continuous-time quantum walk. We demand locality, but allow the walk to vary periodically on a small scale. By…

Quantum Physics · Physics 2014-09-08 Andrew M. Childs , Yimin Ge

We study the quantum walk in momentum space using a coin arranged in quasi-periodic sequences following a Fibonacci prescription. We build for this system a classical map based on the trace of the evolution operator. The sub-ballistic…

Quantum Physics · Physics 2015-05-13 Alejandro Romanelli

Quantum walks are powerful tools for quantum applications and for designing topological systems. Although they are simulated in a variety of platforms, genuine two-dimensional realizations are still challenging. Here we present an…

We study the motion of M particles performing a quantum walk on the line. Under various conditions on the initial coin states for quantum walkers controlled by the Hadamard operator, we give theoretical criterion to observe the quantum…

Quantum Physics · Physics 2011-06-28 Clement Ampadu

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 experimentally demonstrate a method for selecting small regions of phase space for kicked rotor quantum chaos experiments with cold atoms. Our technique uses quantum accelerator modes to selectively accelerate atomic wavepackets with…

Atomic Physics · Physics 2009-11-07 M. B. d'Arcy , R. M. Godun , D. Cassettari , G. S. Summy

We consider one-dimensional quantum walks in optical linear networks with synthetically introduced disorder and tunable system parameters allowing for the engineered realization of distinct topological phases. The option to directly monitor…

We make and generalize the observation that summing of probability amplitudes of a discrete-time quantum walk over partitions of the walking graph consistent with the step operator results in a unitary evolution on the reduced graph which…

Quantum Physics · Physics 2020-04-06 Václav Potoček

We consider the discrete time unitary dynamics given by a quantum walk on the lattice $\Z^d$ performed by a quantum particle with internal degree of freedom, called coin state, according to the following iterated rule: a unitary update of…

Mathematical Physics · Physics 2015-05-20 Alain Joye

The problem of the detection statistics of a quantum walker has received increasing interest, connected as it is to the problem of quantum search. We investigate the effect of employing a moving detector, using a projective measurement…

Statistical Mechanics · Physics 2019-09-04 Dror Meidan , Eli Barkai , David A. Kessler

We study the asymptotic position distribution of general quantum walks on a lattice, including walks with a random coin, which is chosen from step to step by a general Markov chain. In the unitary (i.e., non-random) case, we allow any…

Quantum Physics · Physics 2011-04-21 Andre Ahlbrecht , Holger Vogts , Albert H. Werner , Reinhard F. Werner

We study the discrete-time quantum walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and…

Quantum Physics · Physics 2015-03-17 Scott D. Berry , Jingbo B. Wang

A general approach to obtain reduced models for a wide class of discrete-time quantum systems is proposed. The obtained models not only reproduce exactly the output of a given quantum model, but are also guaranteed to satisfy physical…

Quantum Physics · Physics 2025-09-18 Tommaso Grigoletto , Francesco Ticozzi

We address continuous-time quantum walks on graphs in the presence of time- and space-dependent noise. Noise is modeled as generalized dynamical percolation, i.e. classical time-dependent fluctuations affecting the tunneling amplitudes of…

Quantum Physics · Physics 2019-01-10 Claudia Benedetti , Matteo A. C. Rossi , Matteo G. A. Paris

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

In this tutorial, which contains some original results, we bridge the fields of quantum computing algorithms, conservation laws, and many-body quantum systems by examining three algorithms for searching an unordered database of size $N$…

Quantum Physics · Physics 2025-08-29 David A. Meyer , Thomas G. Wong

In this paper, we introduce hierarchical random walks at first. In this model, we use two types of random walkers, {global and local} walkers. The global walker chooses a local walker at every step, then the chosen local walker moves a…

Quantum Physics · Physics 2025-10-15 Jirô Akahori , Yusuke Ide , Tomoki Kato , Norio Konno , Shuhei Mano , Akihiro Narimatsu

In this survey paper we give an intuitive treatment of the discrete time quantization of classical Markov chains. Grover search and the quantum walk based search algorithms of Ambainis, Szegedy and Magniez et al. will be stated as quantum…

Quantum Physics · Physics 2008-08-04 Miklos Santha

The quantum walk is a quantum counterpart of the classical random walk that exhibits nonclassical behaviors and outperforms the classical random walk in various aspects. It has been known that a single particle can be propagated by a…

Quantum Physics · Physics 2024-12-09 Daer Feng , Shengshi Pang

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