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We study the state transfer through quantum walks placed on a bounded one-dimensional path. We first consider continuous-time quantum walks from a Gaussian state. We find such a state when superposing centered on the starting and antipodal…

Quantum Physics · Physics 2024-03-12 João P. Engster , Rafael Vieira , Eduardo I. Duzzioni , Edgard P. M. Amorim

A continuous-time quantum walk on a graph $G$ is given by the unitary matrix $U(t) = \exp(-itA)$, where $A$ is the Hermitian adjacency matrix of $G$. We say $G$ has pretty good state transfer between vertices $a$ and $b$ if for any…

The adjacency matrix of a graph G is the Hamiltonian for a continuous-time quantum walk on the vertices of G. Although the entries of the adjacency matrix are integers, its eigenvalues are generally irrational and, because of this, the…

We study perfect state transfer in Grover walks, which are typical discrete-time quantum walk models. In particular, we focus on states associated to vertices of a graph. We call such states vertex type states. Perfect state transfer…

Combinatorics · Mathematics 2021-09-15 Sho Kubota , Etsuo Segawa

We prove new results on perfect state transfer of quantum walks on quotient graphs. Since a graph $G$ has perfect state transfer if and only if its quotient $G/\pi$, under any equitable partition $\pi$, has perfect state transfer, we…

Quantum Physics · Physics 2012-11-05 R. Bachman , E. Fredette , J. Fuller , M. Landry , M. Opperman , C. Tamon , A. Tollefson

A discrete-time quantum walk is the quantum analogue of a Markov chain on a graph. Zhan [J. Algebraic Combin. 53(4):1187-1213, 2020] proposes a model of discrete-time quantum walk whose transition matrix is given by two reflections, using…

Combinatorics · Mathematics 2022-11-24 Krystal Guo , Vincent Schmeits

This paper discusses continuous-time quantum walks and asymptotic state transfer in graphs with an involution. By providing quantitative bounds on the eigenvectors of the Hamiltonian, it provides an approach to achieving high-fidelity state…

Quantum Physics · Physics 2023-10-16 Gabor Lippner , Yujia Shi

The transition matrix of a graph $G$ corresponding to the adjacency matrix $A$ is defined by $H(t):=\exp{\left(-itA\right)},$ where $t\in\mathbb{R}$. The graph is said to exhibit pretty good state transfer between a pair of vertices $u$ and…

Combinatorics · Mathematics 2019-01-08 Hiranmoy Pal

We study perfect state transfer in Kendon's model of discrete quantum walks. In particular, we give a characterization of perfect state transfer purely in terms of the graph spectra, and construct an infinite family of $4$-regular circulant…

Combinatorics · Mathematics 2018-08-20 Hanmeng Zhan

We consider a quantum walk with two marked vertices, sender and receiver, and analyze its application to perfect state transfer on complete bipartite graphs. First, the situation with both the sender and the receiver vertex in the same part…

Quantum Physics · Physics 2018-07-26 Martin Stefanak , Stanislav Skoupy

This paper investigates perfect state transfer in Grover walks, a model of discrete-time quantum walks. We establish a necessary and sufficient condition for the occurrence of perfect state transfer on graphs belonging to an association…

Combinatorics · Mathematics 2025-06-23 Koushik Bhakta , Bikash Bhattacharjya

Quantum walks, an important tool in quantum computing, have been very successfully investigated using techniques in algebraic graph theory. We are motivated by the study of state transfer in continuous-time quantum walks, which is…

Combinatorics · Mathematics 2017-10-09 Chris Godsil , Krystal Guo , Mark Kempton , Gabor Lippner

A continuous-time quantum walk on a graph is a matrix-valued function $\exp(-\mathtt{i} At)$ over the reals, where $A$ is the adjacency matrix of the graph. Such a quantum walk has universal perfect state transfer if for all vertices $u,v$,…

Quantum Physics · Physics 2017-01-20 Erin Connelly , Nathaniel Grammel , Michael Kraut , Luis Serazo , Christino Tamon

We consider the representation of a continuous-time quantum walk in a graph $X$ by the matrix $\exp(itA(X))$. We provide necessary and sufficient criteria for distance-regular graphs and, more generally, for graphs in association schemes to…

Combinatorics · Mathematics 2018-05-23 Gabriel Coutinho , Chris Godsil , Krystal Guo , Frédéric Vanhove

We introduce the concept of group state transfer on graphs, summarize its relationship to other concepts in the theory of quantum walks, set up a basic theory, and discuss examples. Let $X$ be a graph with adjacency matrix $A$ and consider…

Quantum Physics · Physics 2021-03-17 Luke C. Brown , William J. Martin , Duncan Wright

In this paper, we study quantum walks on the extension of association schemes. Various state transfers can be achieved on these graphs, such as multiple state transfer among extreme points of a simplex, fractional revival on subsimplexes.…

Quantum Physics · Physics 2023-07-28 Hiroshi Miki , Satoshi Tsujimoto , Da Zhao

A continuous-time quantum random walk describes the motion of a quantum mechanical particle on an underlying graph. The graph itself is associated with a Hilbert space of dimension equal to the number of vertices. The dynamics of the walk…

Quantum Physics · Physics 2021-09-28 Jaideep Mulherkar , Rishikant Rajdeepak , V. Sunitha

The quantum Perfect State Transfer (PST) is a fundamental tool of quantum communication in a network. It is not easy to achieve in practice. The original idea of PST depends on the fundamentals of the continuous-time quantum walk. A path…

Quantum Physics · Physics 2026-02-24 Supriyo Dutta

A continuous-time quantum walk on a graph evolves according to the unitary operator $e^{-iAt}$, where $A$ is the adjacency matrix of the graph. Perfect state transfer (PST) in a quantum walk is the transfer of a quantum state from one node…

Quantum Physics · Physics 2021-11-02 Jaideep Mulherkar , Rishikant Rajdeepak , V. Sunitha

We discuss pretty good state transfer of multiple qubit states and provide a model for considering state transfer of arbitrary states on unmodulated XX-type spin chains. We then provide families of paths and initial states for which we can…

Quantum Physics · Physics 2019-10-21 Christopher M. van Bommel