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In the quest for designing novel protocols for quantum information and quantum computation, an important goal is to achieve perfect quantum state transfer for systems beyond the well-known one dimensional cases, such as 1d spin chains. We…

Mathematical Physics · Physics 2021-08-04 Maxim Derevyagin , Gerald V. Dunne , Gamal Mograby , Alexander Teplyaev

Pretty good state transfer in networks of qubits occurs when a continuous-time quantum walk allows the transmission of a qubit state from one node of the network to another, with fidelity arbitrarily close to 1. We prove that in a…

Quantum Physics · Physics 2018-06-22 Leonardo Banchi , Gabriel Coutinho , Chris Godsil , Simone Severini

A continuous quantum walk on a graph $X$ with adjacency matrix $A$ is specified by the 1-parameter family of unitary matrices $U(t)=\exp(itA)$. These matrices act on the state space of a quantum system, the states of which we may represent…

Combinatorics · Mathematics 2017-10-12 Chris Godsil

We consider quantum state transfer on finite graphs which are attached to infinite paths. The finite graph represents an operational quantum system for performing useful quantum information tasks. In contrast, the infinite paths represent…

Quantum Physics · Physics 2022-11-30 Pierre-Antoine Bernard , Christino Tamon , Luc Vinet , Weichen Xie

A graph is said to exhibit perfect state transfer (PST) if one of its corresponding Hamiltonian matrices, which are based on the vertex-edge structure of the graph, gives rise to PST in a quantum information-theoretic context, namely with…

Combinatorics · Mathematics 2019-06-26 Steve Kirkland , Sarah Plosker , Xiaohong Zhang

Quantum walks, both discrete and continuous, serve as fundamental tools in quantum information processing with diverse applications. This work introduces a hybrid quantum walk model that integrates the coin mechanism of discrete walks with…

Quantum Physics · Physics 2025-09-12 Tianen Chen , Yun Shang

We consider graphs with two cut vertices joined by a path with one or two edges, and prove that there can be no quantum perfect state transfer between these vertices, unless the graph has no other vertex. We achieve this result by applying…

Quantum Physics · Physics 2021-12-08 Gabriel Coutinho , Chris Godsil , Emanuel Juliano , Christopher M. van Bommel

While completely self-avoiding quantum walks have the distinct property of leading to a trivial unidirectional transport of a quantum state, an interesting and non-trivial dynamics can be constructed by restricting the self-avoidance to a…

Quantum Physics · Physics 2015-12-22 Takuya Machida , C. M. Chandrashekar , Norio Konno , Thomas Busch

The ability to accurately transfer quantum information through networks is an important primitive in distributed quantum systems. While perfect quantum state transfer (PST) can be effected by a single particle undergoing continuous-time…

Quantum Physics · Physics 2015-04-01 Steven J. Large , Michael S. Underwood , David L. Feder

An $s$-pair state in a graph is a quantum state of the form $\mathbf{e}_u+s\mathbf{e}_v$, where $u$ and $v$ are vertices in the graph and $s$ is a non-zero complex number. If $s=-1$ (resp., $s=1$), then such a state is called a pair state…

Quantum Physics · Physics 2024-07-30 Sooyeong Kim , Hermie Monterde , Bahman Ahmadi , Ada Chan , Stephen Kirkland , Sarah Plosker

Quantum walks have frequently envisioned the behavior of a quantum state traversing a classically defined, generally finite, graph structure. While this approach has already generated significant results, it imposes a strong assumption: all…

Quantum Physics · Physics 2024-05-28 John C Vining , Howard A. Blair

Coherent evolution governs the behaviour of all quantum systems, but in nature it is often subjected to influence of a classical environment. For analysing quantum transport phenomena quantum walks emerge as suitable model systems. In…

We suggest a scheme that allows arbitrarily perfect state transfer even in the presence of random fluctuations in the couplings of a quantum chain. The scheme performs well for both spatially correlated and uncorrelated fluctuations if they…

Quantum Physics · Physics 2007-05-23 Daniel Burgarth , Sougato Bose

There are presently two models for quantum walks on graphs. The "coined" walk uses discrete time steps, and contains, besides the particle making the walk, a second quantum system, the coin, that determines the direction in which the…

Quantum Physics · Physics 2009-11-10 Mark Hillery , Janos Bergou , Edgar Feldman

The quantum state transmission (QST) through the medium of high-dimensional many-particle system is studied with a symmetry analysis. We discover that, if the spectrum matches the symmetry of a fermion or boson system in a certain fashion,…

Quantum Physics · Physics 2007-05-23 Ying Li , Z. Song , C. P. Sun

In this paper, we study pretty good state transfer (PGST) in Grover walks on graphs. We consider transfer of quantum states that are localized at the vertices of a graph and we use Chebyshev polynomials to analyze PGST between such states.…

Combinatorics · Mathematics 2025-08-14 Koushik Bhakta , Bikash Bhattacharjya

We provide a characterization of perfect state transfer in a quantum walk whose Hamiltonian is given by the normalized Laplacian. We discuss a connection between classical random walks and quantum walks only present in this model, and we…

Quantum Physics · Physics 2022-09-13 Gabriel Coutinho , Pedro Ferreira Baptista

A programmable quantum networks model is used in this paper for development of methods of control of a quantum state transport. These methods may be applied for a wide variety of patterns of controlled state transmission and spreading in…

Quantum Physics · Physics 2007-09-12 Alexander Yu. Vlasov

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…

Quantum state transfer in a triangular domain of a two-dimensional, equally-spaced, spin lat- tice with non-homogeneous nearest-neighbor couplings is analyzed. An exact solution of the one- excitation dynamics is provided in terms of…

Mathematical Physics · Physics 2012-03-13 Hiroshi Miki , Satoshi Tsujimoto , Luc Vinet , Alexei Zhedanov