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We analyze continuous-time quantum and classical random walk on spidernet lattices. In the framework of Stieltjes transform, we obtain density of states, which is an efficiency measure for the performance of classical and quantum mechanical…

Quantum Physics · Physics 2010-04-06 S. Salimi

Let $L$ denote the Laplacian matrix of a graph $G$. We study continuous quantum walks on $G$ defined by the transition matrix $U(t)=\exp\left(itL\right)$. The initial state is of the pair state form, $e_a-e_b$ with $a,b$ being any two…

Combinatorics · Mathematics 2020-09-07 Qiuting Chen , Chris Godsil

The evolution of certain pair state in a quantum network with isomorphic branches, governed by the Heisenberg $XY$ Hamiltonian, depends solely on the local structure, and it remains unaffected even if the global structure is altered. All…

Quantum Physics · Physics 2024-12-10 Hiranmoy Pal , Sarojini Mohapatra

We outline a theory of symmetry protected topological phases of one-dimensional quantum walks. We assume spectral gaps around the symmetry-distinguished points +1 and -1, in which only discrete eigenvalues are allowed. The phase…

Quantum Physics · Physics 2016-04-21 C. Cedzich , F. A. Grünbaum , C. Stahl , L. Velázquez , A. H. Werner , R. F. Werner

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

We investigate coined quantum walk search and state transfer algorithms, focusing on the complete $M$-partite graph with $N$ vertices in each partition. First, it is shown that by adding a loop to each vertex the search algorithm finds the…

Quantum Physics · Physics 2022-12-02 Stanislav Skoupy , Martin Stefanak

Perfect state transfer is significant in quantum communication networks. There are very few graphs having this property. So, it is useful to find some new graphs having perfect state transfer. A good way to construct new graphs is by…

Combinatorics · Mathematics 2019-01-08 Hiranmoy Pal , Bikash Bhattacharjya

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

Consider two random walks on $\mathbb{Z}$. The transition probabilities of each walk is dependent on trajectory of the other walker i.e. a drift $p>1/2$ is obtained in a position the other walker visited twice or more. This simple model has…

Probability · Mathematics 2012-10-30 Noam Berger , Eviatar B. Procaccia

This paper concerns the problem of non-ideal state transfer along the alternating open chain of spins $s=1/2$ with XY Hamiltonian. It is found that the state transfer along the chain with even number of spins $N$ ($N=4,6,8$) may be realized…

Quantum Physics · Physics 2009-11-13 E. I. Kuznetsova , A. I. Zenchuk

We study quantum walks on general graphs from the point of view of scattering theory. For a general finite graph we choose two vertices and attach one half line to each. We are interested in walks that proceed from one half line, through…

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

We study the existence of state transfer with respect to the $q$-Laplacian matrix of a graph equipped with a non-trivial involution. We show that the occurrence of perfect state transfer between certain pair (or plus) states in such a graph…

Combinatorics · Mathematics 2025-09-26 Swornalata Ojha , Hiranmoy Pal

This paper concerns the problem of the high probability state transfer among $2^s$ symmetrically placed nodes of the $N$-nodes spins 1/2 chain with the ${XXZ}$ Hamiltonian. We consider examples with $(N,s)=(4,4)$, $(N,s)=(6,4)$ and…

Quantum Physics · Physics 2009-11-13 E. B. Fel'dman , A. I. Zenchuk

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

Discrete-time quantum walks are well-known for exhibiting localization, a quantum phenomenon where the walker remains at its initial location with high probability. In companion with a joint Letter, we introduce oscillatory localization,…

Quantum Physics · Physics 2016-12-28 Andris Ambainis , Krišjānis Prūsis , Jevgēnijs Vihrovs , Thomas G. Wong

In this article, we propose a quantum communication protocol via 2-step discrete time quantum walks with two coins on a graph of 10 vertices containing both cycles and paths. Quantum walks are known for their ability to integrate quantum…

Quantum Physics · Physics 2025-01-22 Rachana Soni , Neelam Choudhary , Navneet Pratap Singh

We consider the stationary state of a quantum walk on the finite path, where the sink and source are set at the left and right boundaries. The quantum coin is uniformly placed at every vertex of the path graph. At every time step, a new…

Quantum Physics · Physics 2022-03-11 Yoshihiro Anahara , Norio Konno , Hisashi Morioka , Etsuo Segawa

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…

A continuous-time quantum walk is modelled using a graph. In this short paper, we provide lower bounds on the size of a graph that would allow for some quantum phenomena to occur. Among other things, we show that, in the adjacency matrix…

Combinatorics · Mathematics 2018-05-23 Gabriel Coutinho

We study perfect state transfer of quantum walks on signed graphs. Our aim is to show that negative edges are useful for perfect state transfer. Specific results we prove include: (1) The signed join of a negative 2-clique with any positive…

Quantum Physics · Physics 2013-01-17 J. Brown , C. Godsil , D. Mallory , A. Raz , C. Tamon