scholarly journals One-dimensional quantum walks with absorbing boundaries

2004 ◽  
Vol 69 (4) ◽  
pp. 562-592 ◽  
Author(s):  
Eric Bach ◽  
Susan Coppersmith ◽  
Marcel Paz Goldschen ◽  
Robert Joynt ◽  
John Watrous
2021 ◽  
Vol 21 (5&6) ◽  
pp. 395-404
Author(s):  
Ji Guan ◽  
Qisheng Wang ◽  
Mingsheng Ying

We present a novel application of the HHL (Harrow-Hassidim-Lloyd) algorithm --- a quantum algorithm solving systems of linear equations --- in solving an open problem about quantum walks, namely computing hitting (or absorption) probabilities of a general (not only Hadamard) one-dimensional quantum walks with two absorbing boundaries. This is achieved by a simple observation that the problem of computing hitting probabilities of quantum walks can be reduced to inverting a matrix. Then a quantum algorithm with the HHL algorithm as a subroutine is developed for solving the problem, which is faster than the known classical algorithms by numerical experiments.


2015 ◽  
Vol 24 (5) ◽  
pp. 050305 ◽  
Author(s):  
Dan Li ◽  
Michael Mc Gettrick ◽  
Wei-Wei Zhang ◽  
Ke-Jia Zhang

2018 ◽  
Vol 29 (10) ◽  
pp. 1850098 ◽  
Author(s):  
R. F. S. Andrade ◽  
A. M. C. Souza

Properties of one-dimensional discrete-time quantum walks (DTQWs) are sensitive to the presence of inhomogeneities in the substrate, which can be generated by defining position-dependent coin operators. Deterministic aperiodic sequences of two or more symbols provide ideal environments where these properties can be explored in a controlled way. Based on an exhaustive numerical study, this work discusses a two-coin model resulting from the construction rules that lead to the usual fractal Cantor set. Although the fraction of the less frequent coin [Formula: see text] as the size of the chain is increased, it leaves peculiar properties in the walker dynamics. They are characterized by the wave function, from which results for the probability distribution and its variance, as well as the entanglement entropy, were obtained. A number of results for different choices of the two coins are presented. The entanglement entropy has shown to be very sensitive to uncovering subtle quantum effects present in the model.


2010 ◽  
Vol 20 (6) ◽  
pp. 1091-1098 ◽  
Author(s):  
NORIO KONNO

Pólya showed in his 1921 paper that the generating function of the return probability for a two-dimensional random walk can be written in terms of an elliptic integral. In this paper we present a similar expression for a one-dimensional quantum walk.


2021 ◽  
Vol 20 (9) ◽  
Author(s):  
Keisuke Asahara ◽  
Daiju Funakawa ◽  
Motoki Seki ◽  
Yohei Tanaka

2010 ◽  
Vol 10 (5&6) ◽  
pp. 509-524
Author(s):  
M. Mc Gettrick

We investigate the quantum versions of a one-dimensional random walk, whose corresponding Markov Chain is of order 2. This corresponds to the walk having a memory of one previous step. We derive the amplitudes and probabilities for these walks, and point out how they differ from both classical random walks, and quantum walks without memory.


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