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Related papers: Schur States, Average Mixing, and Counting Trees o…

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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

If $X$ is a graph with adjacency matrix $A$, then we define $H(t)$ to be the operator $\exp(itA)$. The Schur (or entrywise) product $H(t)\circ H(-t)$ is a doubly stochastic matrix and, because of work related to quantum computing, we are…

Combinatorics · Mathematics 2011-10-04 Chris Godsil

The weighted spanning tree enumerator of a graph $G$ with weighted edges is the sum of the products of edge weights over all the spanning trees in $G$. In the special case that all of the edge weights equal $1$, the weighted spanning tree…

Combinatorics · Mathematics 2019-09-04 Steven Klee , Matthew T. Stamps

We study the set of probability distributions visited by a continuous-time quantum walk on graphs. An edge-weighted graph G is universal mixing if the instantaneous or average probability distribution of the quantum walk on G ranges over…

Quantum Physics · Physics 2008-06-13 W. Carlson , A. Ford , E. Harris , J. Rosen , C. Tamon , K. Wrobel

A weighted graph $G$ with countable vertex set is bounded if there is an upper bound on the maximum of the sum of absolute values of all edge weights incident to a vertex in $G$. In this paper, we prove a fundamental result on equitable…

Combinatorics · Mathematics 2025-10-08 Chris Godsil , Steve Kirkland , Sarojini Mohapatra , Hermie Monterde , Hiranmoy Pal

In this work we explore the structure of the branching graph of the unitary group using Schur transitions. We find that these transitions suggest a new combinatorial expression for counting paths in the branching graph. This formula, which…

High Energy Physics - Theory · Physics 2016-09-21 Pablo Diaz , Garreth Kemp , Alvaro Veliz-Osorio

In this paper we give a method to associate a graph with an arbitrary density matrix referred to a standard orthonormal basis in the Hilbert space of a finite dimensional quantum system. We study the related issues like classification of…

Quantum Physics · Physics 2007-08-28 Ali Saif M. Hassan , Pramod Joag

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 compute various averages over bulk geometries of quantum states prepared by the Chern-Simons path integral, for any level $k$ and compact simple gauge group $G$. We do so by carefully summing over all topologically distinct bulk…

High Energy Physics - Theory · Physics 2025-07-24 Charlie Cummings

We explore algebraic and spectral properties of weighted graphs containing twin vertices that are useful in quantum state transfer. We extend the notion of adjacency strong cospectrality to arbitrary Hermitian matrices, with focus on the…

Combinatorics · Mathematics 2023-12-29 Hermie Monterde

In this work, we present a theory for topological phases for quantum systems on tree graphs. Conventionally, topological phases of matter have been studied in regular lattices, but also in quasicrystals and amorphous settings. We consider…

Mesoscale and Nanoscale Physics · Physics 2023-02-08 Alex Westström , Wenbu Duan , Kangpei Yao , Xiaonan Wang , Jie Liu , Jian Li

In this article we apply the methods outlined in the previous paper of this series to the particular set of states obtained by choosing the complexifier to be a Laplace operator for each edge of a graph. The corresponding coherent state…

High Energy Physics - Theory · Physics 2009-10-31 T. Thiemann , O. Winkler

We study the topological properties of one-dimensional discrete-time quantum walks with Fibonacci quasiperiodic modulation. Spectral analysis under open boundary conditions reveals isolated edge modes that coexist at both zero and $\pi$…

Quantum Physics · Physics 2026-02-23 F. Iwase

Reinforced random walks are random walks on graphs whose transition probabilities along edges from a vertex are proportional to the weights of those edges, but where the weight of an edge evolves in a way that depends on the past traversals…

Information Theory · Computer Science 2026-05-22 Qinghua , Ding , Venkat Anantharam

In this paper, we are interested in the mixing behaviour of simple random walks on inhomogeneous directed graphs. We focus our study on the Chung-Lu digraph, which is an inhomogeneous network that generalizes the Erd\H{o}s-R\'enyi digraph.…

Probability · Mathematics 2024-09-25 Alessandra Bianchi , Giacomo Passuello

We normalize the combinatorial Laplacian of a graph by the degree sum, look at its eigenvalues as a probability distribution and then study its Shannon entropy. Equivalently, we represent a graph with a quantum mechanical state and study…

Disordered Systems and Neural Networks · Physics 2012-04-24 Filippo Passerini , Simone Severini

We study a family of tree-type diagrams that arise in studies of the cumulant expansion in discrete Erd\H os-R\'enyi random matrix models. Using a version of the Pr\" ufer code, we obtain an explicit expression for the number of tree-type…

Combinatorics · Mathematics 2024-12-16 O. Khorunzhiy

We study the random-cluster model on trees and treelike graphs at low temperatures. This is a model of dependent percolation parametrized by an edge probability $p\in (0,1)$ and a clustering weight $q\in [1,\infty)$, generalizing…

Probability · Mathematics 2026-04-23 Antonio Blanca , Reza Gheissari , Heehyun Park , Xusheng Zhang

We investigate the quantum networks that their nodes are considered as quantum harmonic oscillators. The entanglement of the ground state can be used to quantify the amount of information one part of a network shares with the other part of…

Quantum Physics · Physics 2016-11-25 M. A. Jafarizadeh , F. Eghbalifam , S. Nami

We investigate the entanglement of the ground state in the quantum networks that their nodes are considered as quantum harmonic oscillators. To this aim, the Schmidt numbers and entanglement entropy between two arbitrary partitions of a…

Quantum Physics · Physics 2016-11-25 M. A. Jafarizadeh , S. Nami , F. Eghbalifam
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