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This paper is a sequel to the work of Bhattacharjya et al.\ (J. Phys. A-Math. 57.33: 335303, https://doi.org/10.1088/1751-8121/ad6653) on quantum state transfer on blow-up graphs, where instead of the adjacency matrix, we take the Laplacian…

Combinatorics · Mathematics 2025-04-17 Hermie Monterde , Hiranmoy Pal , Steve Kirkland

Quantum walks on graphs are fundamental to quantum computing and have led to many interesting open problems in algebraic graph theory. This review article highlights three key classes of open problems in this domain; perfect state transfer,…

Combinatorics · Mathematics 2024-04-04 Gabriel Coutinho , Krystal Guo

A simple method for transmitting quantum states within a quantum computer is via a quantum spin chain---that is, a path on $n$ vertices. Unweighted paths are of limited use, and so a natural generalization is to consider weighted paths;…

Quantum Physics · Physics 2019-03-26 Steve Kirkland , Darian McLaren , Rajesh Pereira , Sarah Plosker , Xiaohong Zhang

The interest in quantum walks has been steadily increasing during the last two decades. It is still worth to present new forms of quantum walks that might find practical applications and new physical behaviors. In this work, we define…

Quantum Physics · Physics 2020-04-06 Bruno Chagas , Renato Portugal

For $q\in\mathbb{R}\backslash\{0\}$, the generalized Laplacian of a graph $X$ is the matrix $\mathscr{L}=\Delta+qA$, where $\Delta$ is the degree matrix and $A$ is the adjacency matrix of $X$. In this paper, we investigate perfect state…

Combinatorics · Mathematics 2026-04-23 Swornalata Ojha , Hermie Monterde , Hiranmoy Pal

We present a generalized definition of discrete-time quantum walks convenient for capturing a rather broad spectrum of walker's behavior on arbitrary graphs. It includes and covers both: the geometry of possible walker's positions with…

Quantum Physics · Physics 2019-05-08 Jan Mareš , Jaroslav Novotný , Igor Jex

We consider a system of qubits coupled via nearest-neighbour interaction governed by the Heisenberg Hamiltonian. We further suppose that all coupling constants are equal to $1$. We are interested in determining which graphs allow for a…

Combinatorics · Mathematics 2018-05-23 Gabriel Coutinho , Henry Liu

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 article presents a novel and succinct algorithmic framework via alternating quantum walks, unifying quantum spatial search, state transfer and uniform sampling on a large class of graphs. Using the framework, we can achieve exact…

Quantum Physics · Physics 2025-04-22 Qingwen Wang , Ying Jiang , Lvzhou Li

We consider the Dyson hierarchical graph $\mathcal{G}$, that is a weighted fully-connected graph, where the pattern of weights is ruled by the parameter $\sigma \in (1/2, 1]$. Exploiting the deterministic recursivity through which…

Data Analysis, Statistics and Probability · Physics 2017-04-11 Elena Agliari , Flavia Tavani

Lazy quantum walks were presented by Andrew M. Childs to prove that the continuous-time quantum walk is a limit of the discrete-time quantum walk [Commun.Math.Phys.294,581-603(2010)]. In this paper, we discuss properties of lazy quantum…

Quantum Physics · Physics 2015-09-01 Dan Li , Michael Mc Gettrick , Wei-Wei Zhang , Ke-Jia Zhang

We introduce quantum walks with a time-dependent coin, and show how they include, as a particular case, the generalized quantum walk recently studied by Wojcik et al. {[}Phys. Rev. Lett. \textbf{93}, 180601(2004){]} which exhibits…

Quantum Physics · Physics 2009-11-11 M. C. Banuls , C. Navarrete , A. Perez , Eugenio Roldan , J. C. Soriano

This paper investigates continuous-time quantum walks on directed bipartite graphs based on a graph's adjacency matrix. We prove that on bipartite graphs, probability transport between the two node partitions can be completely suppressed by…

Quantum Physics · Physics 2016-12-07 Beat Tödtli , Monika Laner , Jouri Semenov , Beatrice Paoli , Marcel Blattner , Jérôme Kunegis

Given a graph with Hermitian adjacency matrix $H$, perfect state transfer occurs from vertex $a$ to vertex $b$ if the $(b,a)$-entry of the unitary matrix $\exp(-iHt)$ has unit magnitude for some time $t$. This phenomenon is relevant for…

We develop a general theory of random walks on hypergraphs which includes, as special cases, the different models that are found in literature. In particular, we introduce and analyze general random walk Laplacians for hypergraphs, and we…

Spectral Theory · Mathematics 2021-06-23 Raffaella Mulas , Christian Kuehn , Tobias Böhle , Jürgen Jost

We introduce and study peak state transfer, a notion of high state transfer in qubit networks modeled by continuous-time quantum walks. Unlike perfect or pretty good state transfer, peak state transfer does not require fidelity arbitrarily…

Quantum Physics · Physics 2025-10-02 Gabriel Coutinho , Krystal Guo , Vincent Schmeits

In this paper, a study on discrete-time coined quantum walks on the line is presented. Clear mathematical foundations are still lacking for this quantum walk model. As a step towards this objective, the following question is being…

Quantum Physics · Physics 2013-01-01 Marcos Villagra , Masaki Nakanishi , Shigeru Yamashita , Yasuhiko Nakashima

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

In quantum communication, quantum state transfer from one location to another in a quantum network plays a prominent role, where the impact of noise could be crucial. The idea of state transfer can be fruitfully associated with quantum walk…

Quantum Physics · Physics 2025-12-04 Monika Rani , Supriyo Dutta , Subhashish Banerjee

Quantum walks subject to decoherence generically suffer the loss of their genuine quantum feature, a quadratically faster spreading compared to classical random walks. This intuitive statement has been verified analytically for certain…