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Many current and near-future applications of quantum computing utilise parametric families of quantum circuits and variational methods to find optimal values for these parameters. Solving a quantum computational problem with such…

Quantum Physics · Physics 2025-08-05 Tobias Hartung , Karl Jansen

This paper describes a new QR factorization algorithm which is especially designed for massively parallel platforms combining parallel distributed multi-core nodes. These platforms make the present and the foreseeable future of…

Distributed, Parallel, and Cluster Computing · Computer Science 2012-08-27 Jack Dongarra , Mathieu Faverge , Thomas Herault , Julien Langou , and Yves Robert

This paper proposes a quantum-classical algorithm to evaluate and select classical artificial neural networks architectures. The proposed algorithm is based on a probabilistic quantum memory and the possibility to train artificial neural…

We apply numerical optimization and linear algebra algorithms for classical computers to the problem of automatically synthesizing algorithms for quantum computers. Using our framework, we apply several common techniques from these…

Numerical Analysis · Mathematics 2025-09-16 Yuxin Huang , Benjamin E. Grossman-Ponemon , David A. B. Hyde

We present the NMR implementation of a recently proposed quantum algorithm to find the parity of a permutation. In the usual qubit model of quantum computation, speedup requires the presence of entanglement and thus cannot be achieved by a…

Quantum Physics · Physics 2014-11-17 Shruti Dogra , Arvind , Kavita Dorai

In general, a quantum circuit is constructed with elementary gates, such as one-qubit gates and CNOT gates. It is possible, however, to speed up the execution time of a given circuit by merging those elementary gates together into larger…

Quantum Physics · Physics 2009-11-10 Mikio Nakahara , Yasushi Kondo , Kazuya Hata , Shogo Tanimura

The dominant contribution to communication complexity in factorizing a matrix using QR with column pivoting is due to column-norm updates that are required to process pivot decisions. We use randomized sampling to approximate this process…

Numerical Analysis · Mathematics 2018-01-23 Jed A. Duersch , Ming Gu

By taking into account the physical nature of quantum errors it is possible to improve the efficiency of quantum error correction. Here we consider an optimisation to conventional quantum error correction which involves exploiting…

Quantum Physics · Physics 2007-09-26 Z. W. E. Evans , A. M. Stephens , J. H. Cole , L. C. L. Hollenberg

Quantum algorithms have the potential to enhance machine learning across a variety of domains and applications. In this work, we show how quantum machine learning can be used to improve financial forecasting. First, we use classical and…

Statistical Finance · Quantitative Finance 2024-04-05 Sohum Thakkar , Skander Kazdaghli , Natansh Mathur , Iordanis Kerenidis , André J. Ferreira-Martins , Samurai Brito

We propose a scheme for translating metrological precision bounds into lower bounds on query complexity of quantum search algorithms. Within the scheme the link between quadratic performance enhancement in idealized quantum metrological and…

Quantum Physics · Physics 2016-10-13 Rafal Demkowicz-Dobrzanski , Marcin Markiewicz

Quantum algorithms are getting extremely popular due to their potential to significantly outperform classical algorithms. Yet, applying quantum algorithms to optimization problems meets challenges related to the efficiency of quantum…

We introduce a Sinkhorn-type algorithm for producing quantum permutation matrices encoding symmetries of graphs. Our algorithm generates square matrices whose entries are orthogonal projections onto one-dimensional subspaces satisfying a…

Quantum Algebra · Mathematics 2019-11-13 Ion Nechita , Simon Schmidt , Moritz Weber

We present a quantum algorithm for systems of (possibly inhomogeneous) linear ordinary differential equations with constant coefficients. The algorithm produces a quantum state that is proportional to the solution at a desired final time.…

Quantum Physics · Physics 2017-11-07 Dominic W. Berry , Andrew M. Childs , Aaron Ostrander , Guoming Wang

In this paper, we introduce a classical algorithm for random sampling of permutations, drawing inspiration from the Steinhaus-Johnson-Trotter algorithm. Our approach takes a comprehensive view of permutation sampling by expressing them as…

Quantum Physics · Physics 2025-05-08 Bibhas Adhikari

An efficient decoding algorithm named `divided decoder' is proposed in this paper. Divided decoding can be combined with any decoder using QR-decomposition and offers different pairs of performance and complexity. Divided decoding provides…

Information Theory · Computer Science 2009-01-23 In Sook Park

Variational quantum circuits characterise the state of a quantum system through the use of parameters that are optimised using classical optimisation procedures that typically rely on gradient information. The circuit-execution complexity…

Quantum Physics · Physics 2023-07-28 Sayantan Pramanik , Chaitanya Murti , M Girish Chandra

We discuss the advantages of using the approximate quantum Fourier transform (AQFT) in algorithms which involve periodicity estimations. We analyse quantum networks performing AQFT in the presence of decoherence and show that extensive…

Quantum Physics · Physics 2009-10-30 Adriano Barenco , Artur Ekert , Kalle-Antti Suominen , Päivi Törmä

We discuss the performance of the Search and Fourier Transform algorithms on a hybrid computer constituted of classical and quantum processors working together. We show that this semi-quantum computer would be an improvement over a pure…

Quantum Physics · Physics 2007-05-23 Reinaldo O. Vianna , Wilson R. M. Rabelo , C. H. Monken

The QR algorithm is one of the three phases in the process of computing the eigenvalues and the eigenvectors of a dense nonsymmetric matrix. This paper describes a task-based QR algorithm for reducing an upper Hessenberg matrix to real…

Mathematical Software · Computer Science 2021-12-17 Mirko Myllykoski

We develop a framework for proving rapid convergence of shifted QR algorithms which use Ritz values as shifts, in finite arithmetic. Our key contribution is a dichotomy result which addresses the known forward-instability issues surrounding…

Numerical Analysis · Mathematics 2022-05-16 Jess Banks , Jorge Garza-Vargas , Nikhil Srivastava