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The ability to implement any desired quantum logic gate on a quantum processing unit is equivalent to evolution-operator controllability of the qubits. Conversely, controllability analysis can be used to minimize the resources, i.e., the…

Quantum Physics · Physics 2023-07-19 Fernando Gago-Encinas , Monika Leibscher , Christiane P. Koch

An important result in the theory of quantum control is the "universality" of $2$-local unitary gates, i.e. the fact that any global unitary evolution of a system of $L$ qudits can be implemented by composition of $2$-local unitary gates.…

Quantum Physics · Physics 2026-02-10 Marco Lastres , Frank Pollmann , Sanjay Moudgalya

The symmetries of a finite graph are described by its automorphism group; in the setting of Woronowicz's quantum groups, a notion of a quantum automorphism group has been defined by Banica capturing the quantum symmetries of the graph. In…

Quantum Algebra · Mathematics 2019-07-01 Christian Eder , Viktor Levandovskyy , Julien Schanz , Simon Schmidt , Andreas Steenpass , Moritz Weber

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

Gauge theories are important descriptions for many physical phenomena and systems in quantum computation. Automorphism of gauge group naturally gives global symmetries of gauge theories. In this work we study such symmetries in gauge…

Strongly Correlated Electrons · Physics 2026-05-12 Po-Shen Hsin , Ryohei Kobayashi

We define a notion of quantum automorphism group of Graph C*-algebras for finite, connected graphs. Under the assumption that the underlying graph does not have any multiple edge or loop, the quantum automorphism group of underlying…

Operator Algebras · Mathematics 2018-10-11 Soumalya Joardar , Arnab Mandal

We classify instances of quantum pseudo-telepathy in the graph isomorphism game, exploiting the recently discovered connection between quantum information and the theory of quantum automorphism groups. Specifically, we show that graphs…

Quantum Physics · Physics 2019-05-14 Benjamin Musto , David Reutter , Dominic Verdon

We address the study of controllability of a closed quantum system whose dynamical Lie algebra is generated by adjacency matrices of graphs. We characterize a large family of graphs that renders a system controllable. The key property is a…

Quantum Physics · Physics 2012-01-10 Chris Godsil , Simone Severini

We undertake a study of the notion of a quantum graph over arbitrary finite-dimensional $C^*$-algebras $B$ equipped with arbitrary faithful states. Quantum graphs are realised principally as either certain operators on $L^2(B)$, the quantum…

Operator Algebras · Mathematics 2024-11-27 Matthew Daws

We present an infinite sequence of finite graphs with trivial automorphism group and non-trivial quantum automorphism group. These are the first known examples of graphs with this property. Moreover, to the best of our knowledge, these are…

Quantum Algebra · Mathematics 2025-11-12 Josse van Dobben de Bruyn , David E. Roberson , Simon Schmidt

In 2019, Aterias et al. constructed pairs of quantum isomorphic, non-isomorphic graphs from linear constraint systems. This article deals with quantum automorphisms and quantum isomorphisms of colored versions of those graphs. We show that…

Quantum Algebra · Mathematics 2022-10-03 David Roberson , Simon Schmidt

We introduce the notion of nonlocal symmetry of a graph $G$, defined as a winning quantum correlation for the $G$-automorphism game that cannot be produced classically. Recent connections between quantum group theory and quantum information…

Quantum Algebra · Mathematics 2021-02-11 David E. Roberson , Simon Schmidt

The study of graph C*-algebras has a long history in operator algebras. Surprisingly, their quantum symmetries have never been computed so far. We close this gap by proving that the quantum automorphism group of a finite, directed graph…

Operator Algebras · Mathematics 2018-05-07 Simon Schmidt , Moritz Weber

Recently, the work on quantum automorphism groups of graphs has seen renewed progress, which we expand in this paper. Quantum symmetry is a richer notion of symmetry than the classical symmetries of a graph. In general, it is non-trivial to…

Quantum Algebra · Mathematics 2024-04-24 Julien Schanz

We investigate graphs that can be disconnected into small components by removing a vanishingly small fraction of their vertices. We show that when a quantum network is described by such a graph, the network is efficiently controllable, in…

Quantum Physics · Physics 2017-07-05 Can Gokler , Seth Lloyd , Peter Shor , Kevin Thompson

We prove a number of results to the effect that generic quantum graphs (defined via operator systems as in the work of Duan-Severini-Winter / Weaver) have few symmetries: for a Zariski-dense open set of tuples $(X_1,\cdots,X_d)$ of…

Operator Algebras · Mathematics 2022-03-17 Alexandru Chirvasitu , Mateusz Wasilewski

We present a strong connection between quantum information and quantum permutation groups. Specifically, we define a notion of quantum isomorphisms of graphs based on quantum automorphisms from the theory of quantum groups, and then show…

Quantum Physics · Physics 2018-04-02 Martino Lupini , Laura Mančinska , David E. Roberson

We consider the infinite-dimensional hypercube graph. This graph is not connected and has isomorphic connected components. We describe the restrictions of its automorphisms to the connected components and the automorphism group of connected…

Combinatorics · Mathematics 2011-06-16 Mark Pankov

Quantum control is an important logical primitive of quantum computing programs, and an important concept for equational reasoning in quantum graphical calculi. We show that controlled diagrams in the ZXW-calculus admit rich algebraic…

Quantum Physics · Physics 2026-03-17 Edwin Agnew , Lia Yeh , Richie Yeung

We study Cayley graphs of abelian groups from the perspective of quantum symmetries. We develop a general strategy for determining the quantum automorphism groups of such graphs. Applying this procedure, we find the quantum symmetries of…

Quantum Algebra · Mathematics 2024-02-07 Daniel Gromada
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