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This work describes a new algorithm for creating a superposition over the edge set of a graph, encoding a quantum sample of the random walk stationary distribution. The algorithm requires a number of quantum walk steps scaling as…

Quantum Physics · Physics 2019-04-26 Simon Apers

We implement the proof of principle for the quantum walk of one ion in a linear ion trap. With a single-step fidelity exceeding 0.99, we perform three steps of an asymmetric walk on the line. We clearly reveal the differences to its…

Quantum Physics · Physics 2015-05-13 H. Schmitz , R. Matjeschk , Ch. Schneider , J. Glueckert , M. Enderlein , T. Huber , T. Schaetz

Quantum random walks have been much studied recently, largely due to their highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum random walk on the line: the use of multiple…

Quantum Physics · Physics 2009-11-07 Todd A. Brun , Hilary A. Carteret , Andris Ambainis

In this paper we focus our attention on a particle that follows a unidirectional quantum walk, an alternative version of the nowadays widespread discrete-time quantum walk on a line. Here the walker at each time step can either remain in…

Quantum Physics · Physics 2013-08-01 Miquel Montero

Quantum walks (QWs) describe particles evolving coherently on a lattice. The internal degree of freedom corresponds to a Hilbert space, called coin system. We consider QWs on Cayley graphs of some group $G$. In the literature,…

We consider a periodic quantum graph in the form of a rectangular lattice with the $\delta$-coupling of strength $\gamma$ in the vertices perturbed by changing the latter at an infinite straight array of vertices to a…

Spectral Theory · Mathematics 2024-12-31 Marzieh Baradaran , Pavel Exner , Andrii Khrabustovskyi

Suppose that $k$ runners having different constant speeds run laps on a circular track of unit length. The Lonely Runner Conjecture states that, sooner or later, any given runner will be at distance at least $1/k$ from all the other…

Combinatorics · Mathematics 2012-02-07 Sebastian Czerwiński

We study quantum walk on a ladder with combination of conventional and split-step protocols. The two components of the walk resulting from periodic boundary conditions can be made to have three kinds of probability distributions. Two of…

Quantum Physics · Physics 2020-12-29 Hira Ali , M. Naeem Shahid

Quantum walks constitute an important tool for designing quantum algorithms and information processing tasks. In a lackadaisical walk, in addition to the possibility of moving out of a node, the walker can remain on the same node with some…

Quantum Physics · Physics 2024-05-17 Pranay Naredi , J. Bharathi Kannan , M. S. Santhanam

Quantum walks are well-known for their ballistic dispersion, traveling $\Theta(t)$ away in $t$ steps, which is quadratically faster than a classical random walk's diffusive spreading. In physical implementations of the walk, however, the…

Quantum Physics · Physics 2016-01-25 Thomas G. Wong

It has been proved by Kempe that discrete quantum walks on the hypercube (HC) hit exponentially faster than the classical analog. The same was also observed numerically by Krovi and Brun for a slightly different property, namely, the…

Quantum Physics · Physics 2014-08-20 Adi Makmal , Manran Zhu , Daniel Manzano , Markus Tiersch , Hans J. Briegel

A discrete-time Quantum Walk (QW) is essentially an operator driving the evolution of a single particle on the lattice, through local unitaries. Some QWs admit a continuum limit, leading to familiar PDEs (e.g. the Dirac equation). Recently…

Quantum Physics · Physics 2016-09-21 Pablo Arrighi , Stefano Facchini

A bijection is given between fixed point free involutions of $\{1,2,...,2N\}$ with maximum decreasing subsequence size $2p$ and two classes of vicious (non-intersecting) random walker configurations confined to the half line lattice points…

Combinatorics · Mathematics 2009-11-07 T. H. Baker , P. J. Forrester

In this work, we study the effect of a moving detector on a discrete time one dimensional Quantum Random Walk where the movement is realized in the form of hopping/shifts. The occupation probability $f(x,t;n,s)$ is estimated as the number…

Quantum Physics · Physics 2023-07-10 Md Aquib Molla , Sanchari Goswami

Quantum walks represent an excellent testbed for investigating the interplay between unitary coherent and incoherent dissipative processes. Thanks to photonic quantum interferometers of considerable size, experimental studies could be…

We apply results from Baryshnikov, Brady, Bressler and Pemantle (2008) to compute limiting probability profiles for various quantum random walks in one and two dimensions. Using analytic machinery we show some features of the limit…

Combinatorics · Mathematics 2009-11-23 Andrew Bressler , Torin Greenwood , Robin Pemantle , Marko Petkovsek

Coherence is the most fundamental quantum resource in quantum information processing. How fast a physical system gets coherence or decoherence is a critical ingredient. We present an attainable quantum speed limit based on the variation of…

Quantum Physics · Physics 2025-10-07 Zi-yi Mai , CHang-shui Yu

We show that random walk in uniformly elliptic i.i.d. environment in dimension $\geq5$ has at most one non zero limiting velocity. In particular this proves a law of large numbers in the distributionally symmetric case and establishes…

Probability · Mathematics 2009-09-29 Noam Berger

We take the point of view of a particle performing random walk with bounded jumps on $\mathbb{Z}^d$ in a stationary and ergodic random environment. We prove the quenched large deviation principle (LDP) for the pair empirical measure of the…

Probability · Mathematics 2008-12-17 Atilla Yilmaz

We consider a network model, embedded on the Manhattan lattice, of a quantum localisation problem belonging to symmetry class C. This arises in the context of quasiparticle dynamics in disordered spin-singlet superconductors which are…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 E. J. Beamond , A. L. Owczarek , John Cardy