English
Related papers

Related papers: A quantum walk with a delocalized initial state: c…

200 papers

We consider a two-state quantum walk on a line where after the first step an absorbing sink is placed at the origin. The probability of finding the walker at position $j$, conditioned on that it has not returned to the origin, is…

Quantum Physics · Physics 2018-08-08 Mohamed Sabri , Etsuo Segawa , Martin Stefanak

We analyze the asymptotic scaling of persistence of unvisited sites for quantum walks on a line. In contrast to the classical random walk there is no connection between the behaviour of persistence and the scaling of variance. In…

Quantum Physics · Physics 2016-03-17 Martin Stefanak , Igor Jex

A discrete time quantum walk is considered in which the step lengths are chosen to be either $1$ or $2$ with the additional feature that the walker is persistent with a probability $p$. This implies that with probability $p$, the walker…

Quantum Physics · Physics 2020-04-08 Suchetana Mukhopadhyay , Parongama Sen

Entanglement is a key resource in many quantum information applications and achieving high values independently of the initial conditions is an important task. Here we address the problem of generating highly entangled states in a discrete…

Quantum Physics · Physics 2020-11-25 Aikaterini Gratsea , Friederike Metz , Thomas Busch

We present the first robust implementation of a coined quantum walk over five steps using only passive optical elements. By employing a fiber network loop we keep the amount of required resources constant as the walker's position Hilbert…

Quantum Physics · Physics 2015-05-14 A. Schreiber , K. N. Cassemiro , V. Potocek , A. Gabris , P. J. Mosley , E. Andersson , I. Jex , Ch. Silberhorn

In this study we show a way of achieving the reverse evolution of n-dimensional quantum walks by introducing interventions on the coin degree of freedom during the forward progression of the coin-walker system. Only a single intervention is…

Quantum Physics · Physics 2018-03-23 Mahesh N. Jayakody , Asiri Nanayakkara

We implement a quantum walk in phase space with a new mechanism based on the superconducting resonator-assisted double quantum dots. By analyzing the hybrid system, we obtain the necessary factors of realization of a quantum walk in phase…

Quantum Physics · Physics 2014-07-31 Zhihao Bian , Hao Qin , Xiang Zhan , Rong Zhang , Peng Xue

We consider the effect of different unitary noise mechanisms on the evolution of a quantum walk (QW) on a linear chain with a generic coin operation: (i) bit-flip channel noise, restricted to the coin subspace of the QW, and (ii)…

Quantum Physics · Physics 2007-11-27 G. Abal , R. Donangelo , F. Severo , R. Siri

For a discrete two-state quantum walk (QW) on the half-line with a general condition at the boundary, we formulate and prove a weak limit theorem describing the terminal behavior of its transition probabilities. In this context,…

Quantum Physics · Physics 2015-10-05 Chaobin Liu , Nelson Petulante

Disorder in coined quantum walks generally leads to localization. We investigate the influence of the localization on the entanglement properties of coined quantum walks. Specifically, we consider quantum walks on the line and explore the…

Quantum Physics · Physics 2023-08-30 Louie Hong Yao , Sascha Wald

The preparation of initial superposition states of discrete-time quantum walks (DTQWs) are necessary for the study and applications of DTQWs. In linear optics, it is easy to prepare initial superposition states of the coin, which are always…

We perform a finite-time scaling analysis over the detrapping point of a three-state quantum walk on the line. The coin operator is parameterized by $\rho$ that controls the wavepacket spreading velocity. The input state prepared at the…

Quantum Physics · Physics 2021-11-15 P. R. N. Falcão , A. R. C. Buarque , W. S. Dias , G. M. A. Almeida , M. L. Lyra

In discrete-time quantum walk (DTQW) the walker's coin space entangles with the position space after the very first step of the evolution. This phenomenon may be exploited to obtain the value of the coin parameter $\theta$ by performing…

Quantum Physics · Physics 2019-07-10 Shivani Singh , C. M. Chandrashekar , Matteo G. A. Paris

Quantum walks are promising for information processing tasks because on regular graphs they spread quadratically faster than random walks. Static disorder, however, can turn the tables: unlike random walks, quantum walks can suffer Anderson…

Mesoscale and Nanoscale Physics · Physics 2015-11-18 Tibor Rakovszky , Janos K. Asboth

The study of quantum walk processes has been widely divided into two standard variants, the discrete-time quantum walk (DTQW) and the continuous-time quantum walk (CTQW). The connection between the two variants has been established by…

Quantum Physics · Physics 2008-11-08 C. M. Chandrashekar

We extend the idea of a discrete-time quantum walk on a graph by placing a qubit on each vertex, and allowing the walker to interact with the qubit at its current position. We show that allowing for a controlled-Z interaction at each time…

Quantum Physics · Physics 2016-08-26 Joshua Lockhart , Mauro Paternostro

We study a spin-1/2-particle moving on a one dimensional lattice subject to disorder induced by a random, space-dependent quantum coin. The discrete time evolution is given by a family of random unitary quantum walk operators, where the…

Quantum Physics · Physics 2015-05-27 Andre Ahlbrecht , Volkher B. Scholz , Albert H. Werner

Quantum walks are considered to be quantum counterparts of random walks.They show us impressive probability distributions which are different from those of random walks.That fact has been precisely proved in terms of mathematics and some of…

Quantum Physics · Physics 2016-07-13 Takuya Machida

Quantum walk (QW), which is considered as the quantum counterpart of the classical random walk (CRW), is actually the quantum extension of CRW from the single-coin interpretation. The sequential unitary evolution engenders correlation…

Quantum Physics · Physics 2020-03-11 Jin-Fu Chen , Yu-Han Ma , Chang-Pu Sun

We study a quantum walker on a one-dimensional lattice with a single defect site characterized by a phase. The spread and localization of discrete-time quantum walks starting at the impurity site are affected by the appearance of bound…

Quantum Physics · Physics 2019-05-10 B. Danacı , G. Karpat , İ. Yalçınkaya , A. L. Subaşı