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Related papers: Quantum chromatic numbers via operator systems

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We explore the concept of a graph homomorphism through the lens of C$^*$-algebras and operator systems. We start by studying the various notions of a quantum graph homomorphism and examine how they are related to each other. We then define…

Operator Algebras · Mathematics 2016-02-23 Carlos M. Ortiz , Vern I. Paulsen

We define the Cartesian, Categorical, and Lexicographic, and Strong products of quantum graphs. We provide bounds on the quantum chromatic number of these products in terms of the quantum chromatic number of the factors. To adequately…

Operator Algebras · Mathematics 2024-08-23 Rolando de Santiago , A. Meenakshi McNamara

We study quantum analogs of graph colorings and chromatic number. Initially defined via an interactive protocol, quantum colorings can also be viewed as a natural operator relaxation of graph coloring. Since there is no known algorithm for…

Quantum Physics · Physics 2018-01-12 Laura Mančinska , David E. Roberson

The study of quantum chromatic numbers of graphs is a hot research topic in recent years. However, the infinite family of graphs with known quantum chromatic numbers are rare, as far as we know, the only known such graphs (except for…

Combinatorics · Mathematics 2024-12-31 Xiwang Cao , Keqin Feng , Ying-Ying Tan

The determination of the quantum chromatic number of graphs has attracted considerable attention recently. However, there are few families of graphs whose quantum chromatic numbers are determined. A notable exception is the family of…

Combinatorics · Mathematics 2025-12-02 Tao Luo , Yu Ning , Xiande Zhang

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

First, I introduce quantum graph theory. I also discuss a known lower bound on the independence numbers and derive from it an upper bound on the chromatic numbers of quantum graphs. Then, I construct a family of quantum graphs that can be…

Quantum Physics · Physics 2014-12-01 Steven Lu

We construct a new graph on 120 vertices whose quantum and classical independence numbers are different. At the same time, we construct an infinite family of graphs whose quantum chromatic numbers are smaller than the classical chromatic…

Combinatorics · Mathematics 2024-02-09 Chris Godsil , Mariia Sobchuk

Quantum tomography approaches typically consider a set of observables which we wish to measure, design a measurement scheme which measures each of the observables and then repeats the measurements as many times as necessary. We show that…

Quantum Physics · Physics 2025-01-28 Otto Veltheim , Esko Keski-Vakkuri

Due to its unique computing principles, quantum computing technology will profoundly change the spectacle of color art. Focusing on experimental exploration of color qubit representation, color channel processing, and color image generation…

Quantum Physics · Physics 2025-09-05 Guosheng Hu

The quantum chromatic number, $\chi_q(G)$, of a graph $G$ was originally defined as the minimal number of colors necessary in a quantum protocol in which two provers that cannot communicate with each other but share an entangled state can…

Combinatorics · Mathematics 2018-08-10 Pawel Wocjan , Clive Elphick

We review quantum chaos on graphs. We construct a unitary operator which represents the quantum evolution on the graph and study its spectral and wavefunction statistics. This operator is the analogue of the classical evolution operator on…

Chaotic Dynamics · Physics 2007-05-23 Tsampikos Kottos

We provide formulas for invariants defined on a tensor product of defining representations of unitary groups, under the action of the product group. This situation has a physical interpretation, as it is related to the quantum mechanical…

Representation Theory · Mathematics 2011-11-01 Michael W. Hero , Jeb F. Willenbring , Lauren Kelly Williams

Coloured graphical models are Gaussian statistical models determined by an undirected coloured graph. These models can be described by linear spaces of symmetric matrices. We outline a relationship between the symmetries of the graph and…

Algebraic Geometry · Mathematics 2025-01-14 Isobel Davies , Orlando Marigliano

Tensor network methods are taking a central role in modern quantum physics and beyond. They can provide an efficient approximation to certain classes of quantum states, and the associated graphical language makes it easy to describe and…

Quantum Physics · Physics 2017-08-02 Jacob Biamonte , Ville Bergholm

Quantum computers are expected to give major speed-ups for the simulation of quantum systems. In these conference proceedings, we discuss quantum algorithms for the simulation of perturbative Quantum Chromodynamics (QCD) processes. In…

High Energy Physics - Phenomenology · Physics 2023-09-14 Herschel A. Chawdhry , Mathieu Pellen

A proper vertex colouring of a graph is \emph{nested} if the vertices of each of its colour classes can be ordered by inclusion of their open neighbourhoods. Through a relation to partially ordered sets, we show that the nested chromatic…

Combinatorics · Mathematics 2013-06-04 David Cook

Chromatic quantum contextuality is a criterion of quantum nonclassicality based on (hyper)graph coloring constraints. If a quantum hypergraph requires more colors than the number of outcomes per maximal observable (context), it lacks a…

Quantum Physics · Physics 2025-04-09 Karl Svozil

By a finite type-graph we mean a graph whose set of vertices is the set of all $k$-subsets of $[n]=\{1,2,\ldots, n\}$ for some integers $n\ge k\ge 1$, and in which two such sets are adjacent if and only if they realise a certain order type…

Combinatorics · Mathematics 2017-09-12 Christian Avart , Bill Kay , Christian Reiher , Vojtěch Rödl

Quantum computing (QC) is a new computational paradigm whose foundations relate to quantum physics. Notable progress has been made, driving the birth of a series of quantum-based algorithms that take advantage of quantum computational…

Quantum Physics · Physics 2022-02-22 Yehui Tang , Junchi Yan , Hancock Edwin
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