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Related papers: Quantum Graph Homomorphisms via Operator Systems

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Representing graphs by their homomorphism counts has led to the beautiful theory of homomorphism indistinguishability in recent years. Moreover, homomorphism counts have promising applications in database theory and machine learning, where…

Data Structures and Algorithms · Computer Science 2023-10-16 Jan Böker , Louis Härtel , Nina Runde , Tim Seppelt , Christoph Standke

In this paper, we quantize universal gauge groups such as SU(\infty), as well as their homogeneous spaces, in the sigma-C*-algebra setting. More precisely, we propose concise definitions of sigma-C*-quantum groups and sigma-C*-quantum…

Quantum Algebra · Mathematics 2011-08-31 Snigdhayan Mahanta , Varghese Mathai

We geometrically describe the relation induced on a set of graphs by isomorphism of their associated graph C*-algebras as the smallest equivalence relation generated by five types of moves. The graphs studied have finitely many vertices and…

Operator Algebras · Mathematics 2019-10-28 Sara E. Arklint , Søren Eilers , Efren Ruiz

In this paper, we study multiplicative structures on the K-theory of the core $A:=C^*(E)^{U(1)}$ of the C*-algebra $C^*(E)$ of a directed graph $E$. In the first part of the paper, we study embeddings $E\to E\times E$ that induce a…

K-Theory and Homology · Mathematics 2026-04-15 Francesco D'Andrea

A quantum graph $\mathcal{G}$ housed by a matrix algebra $M_n$ can be encoded as an operator system $\mathcal S=\mathcal{S}_{\mathcal{G}}\le M_n$. There are two sensible notions of quantum automorphism group for any such:…

Quantum Algebra · Mathematics 2025-11-18 Alexandru Chirvasitu , Piotr M. Sołtan , Mateusz Wasilewski

Current quantum computing devices have different strengths and weaknesses depending on their architectures. This means that flexible approaches to circuit design are necessary. We address this task by introducing a novel space-efficient…

We introduce a new graph invariant that measures fractional covering of a graph by cuts. Besides being interesting in its own right, it is useful for study of homomorphisms and tension-continuous mappings. We study the relations with…

Combinatorics · Mathematics 2015-11-24 Robert Šámal

The harmonious chromatic number of a graph $G$ is the minimum number of colors that can be assigned to the vertices of $G$ in a proper way such that any two distinct edges have different color pairs. This paper gives various results on…

We compute numerically the homology of several graph complexes in low loop orders, extending previous results.

Quantum Algebra · Mathematics 2023-12-21 Simon Brun , Thomas Willwacher

We explore the connection between ring homomorphisms and semigroup homomorphisms on matrix algebras over rings or $C^*$-algebras.

Operator Algebras · Mathematics 2017-01-24 Bernhard Burgstaller

In this work, we propose novel families of positional encodings tailored to graph neural networks obtained with quantum computers. These encodings leverage the long-range correlations inherent in quantum systems that arise from mapping the…

A quantum set is defined to be simply a set of nonzero finite-dimensional Hilbert spaces. Together with binary relations, essentially the quantum relations of Weaver, quantum sets form a dagger compact category. Functions between quantum…

Operator Algebras · Mathematics 2021-10-13 Andre Kornell

We determine the optimum topology of quasi-one dimensional nonlinear optical structures using generalized quantum graph models. Quantum graphs are relational graphs endowed with a metric and a multiparticle Hamiltonian acting on the edges,…

Quantum Physics · Physics 2015-06-19 Rick Lytel , Shoresh Shafei , Mark G. Kuzyk

We show that quantum graph parameters for finite, simple, undirected graphs encode winning strategies for all possible synchronous non-local games. Given a synchronous game $\mathcal{G}=(I,O,\lambda)$ with $|I|=n$ and $|O|=k$, we…

Quantum Physics · Physics 2023-07-12 Samuel J. Harris

We summarize different approaches to the theory of quantum graphs and provide several ways to construct concrete examples. First, we classify all undirected quantum graphs on the quantum space $M_2$. Secondly, we apply the theory of…

Quantum Algebra · Mathematics 2022-12-15 Daniel Gromada

We introduce notions of being "triangle-free" and "strongly triangle-free" for operator systems in M_n(C) considered as quantum graphs. Several examples and non-examples are discussed. We provide a complete characterization of strongly…

Operator Algebras · Mathematics 2025-09-23 Nik Weaver

Quantum graphs have attracted attention from mathematicians for some time. A quantum graph is defined by having a Laplacian on each edge of a metric graph and imposing boundary conditions at the vertices to get an eigenvalue problem. A…

Spectral Theory · Mathematics 2022-07-26 Mats-Erik Pistol , Pavel Kurasov

We investigate the notion of quantum chromatic number of a graph, which is the minimal number of colours necessary in a protocol in which two separated provers can convince an interrogator with certainty that they have a colouring of the…

Quantum Physics · Physics 2011-11-09 Peter J. Cameron , Ashley Montanaro , Michael W. Newman , Simone Severini , Andreas Winter

Algebro-geometric methods have proven to be very successful in the study of graphical models in statistics. In this paper we introduce the foundations to carry out a similar study of their quantum counterparts. These quantum graphical…

Algebraic Geometry · Mathematics 2023-08-23 Eliana Duarte , Dmitrii Pavlov , Maximilian Wiesmann

Several quantum systems have been used in the last few years to extend supersymmetry. In this paper we show all this systems fit into the picture of what we call "Number Operator Algebras".

Mathematical Physics · Physics 2007-05-23 Fabien Besnard