Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Riemann curvature in quantum computational geometry

Howard E. Brandt

Published Mar 24, 2009• 0 citations
Publisher

Abstract

In the Riemannian geometry of quantum computation, the quantum evolution is described in terms of the special unitary group SU(2n) of n-qubit unitary operators with unit determinant. To elaborate on one aspect of the methodology, the Riemann curvature and sectional curvature are explicitly derived using the Lie algebra su(2n). This is important for investigations of the global characteristics of geodesic paths in the group manifold.

DOI
10.1117/12.820876

Related papers

ASPECTS OF THE RIEMANNIAN GEOMETRY OF QUANTUM COMPUTATION

Howard E. Brandt

A review is given of some aspects of the Riemannian geometry of quantum computation in which the quantum evolution is represented in the tangent space manifold of the special unitary unimodular group SU(2n) for n qubits. The Riemannian right-invariant metric, connection, curvature, geodesic equation for minimal complexity quantum circuits, Jacobi equation and the lifted Jacobi equation for varying penalty parameter are reviewed. Sharpened tools for calculating the geodesic derivative are presented. The geodesic derivative may facilitate the numerical investigation of conjugate points and the global characteristics of geodesic paths in the group manifold, the determination of optimal quantum circuits for carrying out a quantum computation, and the determination of the complexity of particular quantum algorithms.

International Journal of Modern Physics B•Sep 18, 2012•2 citations

Jacobi fields in the Riemannian geometry of quantum computation

Howard E. Brandt

In the Riemannian geometry of quantum computation, the quantum evolution is described in terms of the special unitary group of n-qubit unitary operators with unit determinant. To elaborate on some aspects of the methodology, the generic Jacobi equation and lifted Jacobi equation, together with solutions on the group manifold, are explicitly derived. This is important for investigations of the global characteristics of geodesic paths in the group manifold, and the determination of optimal quantum circuits for carrying out a quantum computation.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 31, 2010•2 citations

Lifted Jacobi equation for varying penalty parameter in the Riemannian geometry of quantum computation

Howard E. Brandt

Recent developments in the differential geometry of quantum computation are exposited. The quantum evolution is described in terms of the special unitary group of n-qubit unitary operators with unit determinant. The group manifold is taken to be Riemannian. In the present work, the lifted Jacobi equation and geodesic derivative are reviewed. This is applicable to investigations of conjugate points and the global characteristics of geodesic paths in the group manifold, and the determination of optimal quantum circuits for carrying out a quantum computation.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 31, 2010•1 citation

Differential geometry of quantum computing

Howard E. Brandt

An expository review is given of recent developments in the differential geometry of quantum computation. Descriptions are given of the appropriate Riemannian geometry of the special unitary unimodular group in 2n- dimensions, including the choice of metric, connection, curvature tensor, and optimal geodesics for achieving minimal complexity quantum computations.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 6, 2008•1 citation

Geodesics of Quantum Feature Maps on the Space of Quantum Operators

Andrew Vlasic

Recent advancements in the discipline of quantum algorithms have displayed the importance of the geometry of quantum operators. Given this thrust, this paper develops a rigorous geometric framework to analyze how the Riemannian structure of data, under the manifold hypothesis, influences the subspace of quantum gates induced by quantum feature maps. While numerous encoding schemes have been proposed in quantum machine learning, little attention has been given to how data geometry is deformed when mapped into the Lie group of special unitary operators. Addressing this gap, we assume a point cloud forms a smooth Riemannian manifold and formally construct the induced Riemannian geometry of a broad class of Hamiltonian quantum feature maps, which encompasses the majority of derived schemes. Starting from first principles, we derive analytic and, consequently, computational formulas for fundamental geometric measurements, including curvature, volume forms, and harmonic maps, providing tools for systematic deformation analysis. Notably, the derivations of the formulas elucidates how changes along paths in the data manifold interplay to changes in the associated subspace of special unitary operators, thereby indicating a direct geometric effect of data on quantum circuits. This framework establishes the mathematical validity required for principled analysis beyond heuristic ansatz and enables future research into geometry-aware quantum algorithm design.

arXiv:2509.02795•Sep 2, 2025•0 citations

Aspects of quantum computational geodesics

Howard E. Brandt

The object of this paper is to mathematically investigate characteristics of a geodesic equation describing possible minimum complexity paths in the special unitary group manifold representing the unitary evolution of n qubits associated with a quantum computation. Simple solutions are elaborated for the case of three qubits.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 24, 2009•1 citation
In the Riemannian geometry of quantum computation, the quantum evolution is described in terms of the special unitary group SU(2n) of n-qubit unitary operators with unit determinant. To elaborate on one aspect of the methodology, the Riemann curvature and sectional curvature are explicitly derived using the Lie algebra su(2n). This is important for investigations of the global characteristics of geodesic paths in the group manifold.
A review is given of some aspects of the Riemannian geometry of quantum computation in which the quantum evolution is represented in the tangent space manifold of the special unitary unimodular group SU(2n) for n qubits. The Riemannian right-invariant metric, connection, curvature, geodesic equation for minimal complexity quantum circuits, Jacobi equation and the lifted Jacobi equation for varying penalty parameter are reviewed. Sharpened tools for calculating the geodesic derivative are presented. The geodesic derivative may facilitate the numerical investigation of conjugate points and the global characteristics of geodesic paths in the group manifold, the determination of optimal quantum circuits for carrying out a quantum computation, and the determination of the complexity of particular quantum algorithms.
In the Riemannian geometry of quantum computation, the quantum evolution is described in terms of the special unitary group of n-qubit unitary operators with unit determinant. To elaborate on some aspects of the methodology, the generic Jacobi equation and lifted Jacobi equation, together with solutions on the group manifold, are explicitly derived. This is important for investigations of the global characteristics of geodesic paths in the group manifold, and the determination of optimal quantum circuits for carrying out a quantum computation.
Recent developments in the differential geometry of quantum computation are exposited. The quantum evolution is described in terms of the special unitary group of n-qubit unitary operators with unit determinant. The group manifold is taken to be Riemannian. In the present work, the lifted Jacobi equation and geodesic derivative are reviewed. This is applicable to investigations of conjugate points and the global characteristics of geodesic paths in the group manifold, and the determination of optimal quantum circuits for carrying out a quantum computation.
Recent advancements in the discipline of quantum algorithms have displayed the importance of the geometry of quantum operators. Given this thrust, this paper develops a rigorous geometric framework to analyze how the Riemannian structure of data, under the manifold hypothesis, influences the subspace of quantum gates induced by quantum feature maps. While numerous encoding schemes have been proposed in quantum machine learning, little attention has been given to how data geometry is deformed when mapped into the Lie group of special unitary operators. Addressing this gap, we assume a point cloud forms a smooth Riemannian manifold and formally construct the induced Riemannian geometry of a broad class of Hamiltonian quantum feature maps, which encompasses the majority of derived schemes. Starting from first principles, we derive analytic and, consequently, computational formulas for fundamental geometric measurements, including curvature, volume forms, and harmonic maps, providing tools for systematic deformation analysis. Notably, the derivations of the formulas elucidates how changes along paths in the data manifold interplay to changes in the associated subspace of special unitary operators, thereby indicating a direct geometric effect of data on quantum circuits. This framework establishes the mathematical validity required for principled analysis beyond heuristic ansatz and enables future research into geometry-aware quantum algorithm design.