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Partition of unity methods (PUMs) on graphs are simple and highly adaptive auxiliary tools for graph signal processing. Based on a greedy-type metric clustering and augmentation scheme, we show how a partition of unity can be generated in…

Signal Processing · Electrical Eng. & Systems 2020-12-22 Roberto Cavoretto , Alessandra De Rossi , Wolfgang Erb

A general scheme is presented to decompose a $d$-by-$d$ unitary matrix as the product of two-level unitary matrices with additional structure and prescribed determinants. In particular, the decomposition can be done by using two-level…

Quantum Physics · Physics 2013-03-11 Chi-Kwong Li , Rebecca Roberts , Xiaoyan Yin

Matrix representations of quantum operators are computationally complete but often obscure the structural topology of information flow within a quantum circuit \cite{nielsen2000}. In this paper, we introduce a generalized graph-theoretic…

Quantum Physics · Physics 2026-03-03 Wesley Lewis , Darsh Pareek , Umesh Kumar , Ravi Janjam

Graph states are key resources for measurement-based quantum computing, which is particularly promising for photonic systems. Fusions are probabilistic Bell state measurements, measuring pairs of parity operators of two qubits. Fusions can…

Quantum Physics · Physics 2025-07-21 Matthias C. Löbl , Love A. Pettersson , Stefano Paesani , Anders S. Sørensen

Entangled multipartite states are resources for universal quantum computation, but they can also give rise to ensembles of unitary transformations, a topic usually studied in the context of random quantum circuits. Using several graph state…

Quantum Physics · Physics 2016-05-25 Peter S. Turner , Damian Markham

Image-based data is a popular arena for testing quantum machine learning algorithms. A crucial factor in realizing quantum advantage for these applications is the ability to efficiently represent images as quantum states. Here we present a…

Quantum Physics · Physics 2023-10-10 Jason Iaconis , Sonika Johri

In frameworks of the phenomenological approach we analyze of the phase diagram of mixed compounds. We obtain space groups of symmetry of the real structures as result of phase transition from close-packed degenerate structure. The theory of…

Statistical Mechanics · Physics 2007-05-23 B. R. Gadjiev

A fundamental problem in quantum information is to describe efficiently multipartite quantum states. An efficient representation in terms of graphs exists for several families of quantum states (graph, cluster, stabilizer states),…

Quantum Physics · Physics 2012-07-04 Radu Ionicioiu , Tim P. Spiller

The classification of quantum phases of matter remains a fundamental challenge in condensed matter physics. We present a novel framework that combines shadow tomography with modern time-series machine learning models to enable efficient and…

Quantum Physics · Physics 2025-08-08 Weicheng Ye , Shuwei Liu , Shiyu Zhou , Yijian Zou

Quantum process tomography conventionally uses a multitude of initial quantum states and then performs state tomography on the process output. Here we propose and study an alternative approach which requires only a single (or few) known…

Quantum Physics · Physics 2023-11-09 Irene López Gutiérrez , Felix Dietrich , Christian B. Mendl

The study of quantum evolution on graphs for diversified topologies is beneficial to modeling various realistic systems. A systematic method, the dimerized decomposition, is proposed to analyze the dynamics on an arbitrary network. By…

Quantum Physics · Physics 2020-03-04 He Feng , Tian-Min Yan , Y. H. Jiang

The ability to perform a universal set of quantum operations based solely on static resources and measurements presents us with a strikingly novel viewpoint for thinking about quantum computation and its powers. We consider the two major…

Quantum Physics · Physics 2007-05-23 Panos Aliferis , Debbie W. Leung

Continuous-variable cluster states offer a potentially promising method of implementing a quantum computer. This paper extends and further refines theoretical foundations and protocols for experimental implementation. We give a…

Quantum Physics · Physics 2015-05-13 Mile Gu , Christian Weedbrook , Nicolas C. Menicucci , Timothy C. Ralph , Peter van Loock

We examine the use of string diagrams and the mathematics of category theory in the description of quantum states by tensor networks. This approach lead to a unification of several ideas, as well as several results and methods that have not…

Quantum Physics · Physics 2015-03-17 Jacob D. Biamonte , Stephen R. Clark , Dieter Jaksch

We consider a variant of the phase retrieval problem, where vectors are replaced by unitary matrices, i.e., the unknown signal is a unitary matrix U, and the measurements consist of squared inner products |Tr(C*U)|^2 with unitary matrices C…

Quantum Physics · Physics 2018-03-07 Shelby Kimmel , Yi-Kai Liu

In this article, we establish a mathematical framework that utilizes concepts from graph theory to formalize the parity transformation, an encoding strategy for compiling optimization problems on quantum devices. We introduce the…

Quantum Physics · Physics 2026-01-27 Florian Dreier , Wolfgang Lechner

We consider graph states generated by the action of controlled phase shift operators on a separable state of a multi-qubit system. The case when all the qubits are initially prepared in arbitrary states is investigated. We obtain the…

Quantum Physics · Physics 2024-01-29 N. A. Susulovska

Topological order of a topological phase of matter in two spacial dimensions is encoded by a unitary modular (tensor) category (UMC). A group symmetry of the topological phase induces a group symmetry of its corresponding UMC. Gauging is a…

Quantum Algebra · Mathematics 2017-04-25 Shawn X. Cui , César Galindo , Julia Yael Plavnik , Zhenghan Wang

In this article we provide necessary and sufficient conditions for a completely positive trace-preserving (CPT) map to be decomposable into a convex combination of unitary maps. Additionally, we set out to define a proper distance measure…

Quantum Physics · Physics 2013-04-25 Koenraad M. R. Audenaert , Stefan Scheel

Diagrammatic representation and manipulation of tensor networks has proven to be a useful tool in mathematics, physics, and computer science. Here we present several important and mostly well-known theorems regarding the dualities between…

Quantum Physics · Physics 2015-09-29 Ville Bergholm