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In this note we explain the method how to find the resonance condition on quantum graphs, which is called pseudo orbit expansion. In three examples with standard coupling we show in detail how to obtain the resonance condition. We focus on…

Mathematical Physics · Physics 2023-07-19 Jiri Lipovsky

We investigate spectral properties of Kirchhoff Laplacians on radially symmetric antitrees. This class of metric graphs enjoys a rich group of symmetries, which enables us to obtain a decomposition of the corresponding Laplacian into the…

Spectral Theory · Mathematics 2021-09-07 Aleksey Kostenko , Noema Nicolussi

We consider the dynamics of relativistic spin-half particles in quantum graphs with transparent branching points. The system is modeled by combining the quantum graph concept with the one of transparent boundary conditions applied to the…

Quantum Physics · Physics 2020-07-01 J. R. Yusupov , K. K. Sabirov , Q. U. Asadov , M. Ehrhardt , D. U. Matrasulov

We analyze spectral properties of a quantum graph in the form of a ring chain with a $\delta$ coupling in the vertices exposed to a homogeneous magnetic field perpendicular to the graph plane. We find the band spectrum in the case when the…

Mathematical Physics · Physics 2019-12-10 Pavel Exner , Stepan S. Manko

Quantum graphs have recently emerged as models of nonlinear optical, quantum confined systems with exquisite topological sensitivity and the potential for predicting structures with an intrinsic, off-resonance response approaching the…

Optics · Physics 2013-05-21 Rick Lytel , Shoresh Shafei , Mark G. Kuzyk

The paper is concerned with the number of open gaps in spectra of periodic quantum graphs. The well-known conjecture by Bethe and Sommerfeld (1933) says that the number of open spectral gaps for a system periodic in more than one direction…

Mathematical Physics · Physics 2017-11-16 Pavel Exner , Ondřej Turek

In this paper we study the asymptotic distribution of the cuspidal spectrum of arithmetic quotients of the symmetric space S=SL(n,R)/SO(n). In particular, we obtain Weyl's law with an estimation on the remainder term. This extends results…

Representation Theory · Mathematics 2019-12-19 Erez Lapid , Werner Mueller

A general analytical approach to the statistical description of quantum graph spectra based on the exact periodic orbit expansions of quantum levels is discussed. The exact and approximate expressions obtained in \cite{Anima} for the…

Quantum Physics · Physics 2007-05-23 Yu. Dabaghian

We define the independence ratio and the chromatic number for bounded, self-adjoint operators on an L^2-space by extending the definitions for the adjacency matrix of finite graphs. In analogy to the Hoffman bounds for finite graphs, we…

Functional Analysis · Mathematics 2014-10-07 Christine Bachoc , Evan DeCorte , Fernando Mario de Oliveira Filho , Frank Vallentin

We compute the spectrum for a class of quantum Markov semigroups describing systems of $N$ particle interacting through a binary collision mechanism. These quantum Markov semgroups are associated to a novel kind of quantum random walk on…

Combinatorics · Mathematics 2023-12-12 Eric A. Carlen , Michael P. Loss

We study the distribution of eigenvalues for non-selfadjoint perturbations of selfadjoint semiclassical analytic pseudodifferential operators in dimension two, assuming that the classical flow of the unperturbed part is completely…

Spectral Theory · Mathematics 2015-05-27 Michael Hitrik , Johannes Sjoestrand

Quantum self-testing is the task of certifying quantum states and measurements using the output statistics solely, with minimal assumptions about the underlying quantum system. It is based on the observation that some extremal points in the…

Quantum Physics · Physics 2023-09-07 Kishor Bharti , Maharshi Ray , Zhen-Peng Xu , Masahito Hayashi , Leong-Chuan Kwek , Adán Cabello

In this study we investigate the bound states of the Hamiltonian describing a quantum particle living on three dimensional straight strip of width $d$. We impose the Neumann boundary condition on a disc window of radius $a$ and Dirichlet…

Spectral Theory · Mathematics 2026-02-10 S. Ben Hariz , M. Ben Salah , H. Najar

We study the spectral statistics of quantum (metric) graphs whose vertices are equipped with preferred orientation vertex conditions. When comparing their spectral statistics to those predicted by suitable random matrix theory ensembles,…

Spectral Theory · Mathematics 2025-08-08 Ram Band , Pavel Exner , Divya Goel , Aviya Strauss

The "noncommutative graphs" which arise in quantum error correction are a special case of the quantum relations introduced in [N. Weaver, Quantum relations, Mem. Amer. Math. Soc. 215 (2012), v-vi, 81-140]. We use this perspective to…

Operator Algebras · Mathematics 2017-06-30 Nik Weaver

We study Schr\"odinger operators on compact finite metric graphs subject to $\delta'$-coupling conditions. Based on a novel modified local Weyl law, we derive an explicit expression for the limiting mean eigenvalue distance of two different…

Spectral Theory · Mathematics 2025-04-02 Patrizio Bifulco , Joachim Kerner

We consider magnetic Schroedinger operators on quantum graphs with identical edges. The spectral problem for the quantum graph is reduced to the discrete magnetic Laplacian on the underlying combinatorial graph and a certain Hill operator.…

Mathematical Physics · Physics 2007-05-23 Konstantin Pankrashkin

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

In this paper we study spectral properties of adjacency and Laplace operators on percolation subgraphs of Cayley graphs of amenable, finitely generated groups. In particular we describe the asymptotic behaviour of the integrated density of…

Spectral Theory · Mathematics 2008-11-27 Tonći Antunović , Ivan Veselić

We study the spectra of quantum graphs with the method of trace identities (sum rules), which are used to derive inequalities of Lieb-Thirring, Payne-P\'olya-Weinberger, and Yang types, among others. We show that the sharp constants of…

Spectral Theory · Mathematics 2015-05-14 Semra Demirel , Evans M. Harrell
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