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Quantum graphs are a paradigmatic model for quantum chaos as well as for spectral theory. We give a concise didactical introduction to quantum graphs, or Schr\"odinger Hamiltonians on metric graphs, with a focus on results related to…

Quantum Physics · Physics 2026-05-07 Gregory Berkolaiko , Sven Gnutzmann

This work deals with the average scattering entropy of quantum graphs. We explore this concept in several distinct scenarios that involve periodic, aperiodic and random distribution of vertices of distinct degrees. In particular, we compare…

Quantum Physics · Physics 2022-04-13 Alison A. Silva , Fabiano M. Andrade , D. Bazeia

In this work a Green function approach for scattering quantum walks is developed. The exact formula has the form of a sum over paths and always can be cast into a closed analytic expression for arbitrary topologies and position dependent…

Quantum Physics · Physics 2011-12-13 F. M. Andrade , M. G. E. da Luz

In this paper, we discuss the concept of quantum graphs with transparent vertices by considering the case where the graph interacts with an external time-independent field. In particular, we address the problem of transparent boundary…

Quantum Physics · Physics 2023-12-05 J. R. Yusupov , M. Ehrhardt , Kh. Sh. Matyokubov , D. U. Matrasulov

We provide an introductory review of some topics in spectral theory of Laplacians on metric graphs. We focus on three different aspects: the trace formula, the self-adjointness problem and connections between Laplacians on metric graphs and…

Spectral Theory · Mathematics 2022-09-08 Noema Nicolussi

Quantum graphs have been introduced by Duan, Severini, and Winter to describe the zero-error behaviour of quantum channels. Since then, quantum graph theory has become a field of study in its own right. A substantial source of difficulty in…

Operator Algebras · Mathematics 2026-04-20 Gian Luca Spitzer , Ion Nechita

Spectral characterization of graphs is an important topic in spectral graph theory, which has received a lot of attention from researchers in recent years. It is generally very hard to show a given graph to be determined by its spectrum.…

Combinatorics · Mathematics 2021-08-03 Lihong Qiu , Wei Wang , Wei Wang , Hao Zhang

We present an exact analytical solution of the spectral problem of quasi one-dimensional scaling quantum graphs. Strongly stochastic in the classical limit, these systems are frequently employed as models of quantum chaos. We show that…

Quantum Physics · Physics 2007-05-23 Yu. Dabaghian , R. Blümel

Quantum graphs were introduced to model free electrons in organic molecules using a self-adjoint Hamiltonian on a network of intervals. A second graph quantization describes wave propagation on a graph by specifying scattering matrices at…

Mathematical Physics · Physics 2024-02-20 Jon Harrison

We study transport in quantum systems consisting of a finite array of N identical single-channel scatterers. A general expression of the S matrix in terms of the individual-element data obtained recently for potential scattering is…

Quantum Physics · Physics 2007-05-23 Pavel Exner , Milos Tater , David Vanek

A continuous-time quantum walk on a dynamic graph evolves by Schr\"odinger's equation with a sequence of Hamiltonians encoding the edges of the graph. This process is universal for quantum computing, but in general, the dynamic graph that…

Quantum Physics · Physics 2022-01-20 Rebekah Herrman , Thomas G. Wong

We investigate the bottom of the spectra of infinite quantum graphs, i.e., Laplace operators on metric graphs having infinitely many edges and vertices. We introduce a new definition of the isoperimetric constant for quantum graphs and then…

Spectral Theory · Mathematics 2018-12-17 Aleksey Kostenko , Noema Nicolussi

A unification of characteristic mode decomposition for all method-of-moment formulations of field integral equations describing free-space scattering is derived. The work is based on an algebraic link between impedance and transition…

Classical Physics · Physics 2023-01-04 Mats Gustafsson , Lukas Jelinek , Kurt Schab , Miloslav Capek

In contrast to the usual quantum systems which have at most a finite number of open spectral gaps if they are periodic in more than one direction, periodic quantum graphs may have gaps arbitrarily high in the spectrum. This property of…

Quantum Physics · Physics 2020-05-26 Pavel Exner , Ondřej Turek

Quantum graphity is a background independent model for emergent locality, spatial geometry and matter. The states of the system correspond to dynamical graphs on N vertices. At high energy, the graph describing the system is highly…

High Energy Physics - Theory · Physics 2008-11-26 Tomasz Konopka , Fotini Markopoulou , Simone Severini

Trace formulae provide one of the most elegant descriptions of the classical-quantum correspondence. One side of a formula is given by a trace of a quantum object, typically derived from a quantum Hamiltonian, and the other side is…

Spectral Theory · Mathematics 2007-05-23 Johannes Sjoestrand , Maciej Zworski

The aim of the present article is to give an overview of spectral theory on metric graphs guided by spectral geometry on discrete graphs and manifolds. We present the basic concept of metric graphs and natural Laplacians acting on it and…

Combinatorics · Mathematics 2008-02-15 Olaf Post

We systematise and develop a graphical approach to the investigations of quantum integrable vertex statistical models and the corresponding quantum spin chains. The graphical forms of the unitarity and various crossing relations are…

Mathematical Physics · Physics 2019-09-16 Khazret S. Nirov , Alexander V. Razumov

Transformers have demonstrated success in graph learning, particularly for node-level tasks. However, existing methods encounter an information bottleneck when generating graph-level representations. The prevalent single token paradigm…

Machine Learning · Computer Science 2026-02-11 Ruixiang Wang , Yuyang Hong , Shiming Xiang , Chunhong Pan

We construct an effective Quantum Field Theory for the wrapping effects in 1+1 dimensional models of factorised scattering. The recently developed graph-theoretical approach to TBA gives the perturbative desctiption of this QFT. For the…

High Energy Physics - Theory · Physics 2022-05-06 Ivan Kostov