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Noncommutative or quantum Riemannian geometry has been proposed as an effective theory for aspects of quantum gravity. Here the metric is an invertible bimodule map $\Omega^1\otimes_A\Omega^1\to A$ where $A$ is a possibly noncommutative or…

Quantum Algebra · Mathematics 2018-04-18 Shahn Majid , Liam Williams

We study de Rham cohomology for various differential calculi on finite groups G up to order 8. These include the permutation group S_3, the dihedral group D_4 and the quaternion group Q. Poincare' duality holds in every case, and under some…

Mathematical Physics · Physics 2009-11-07 L. Castellani , R. Catenacci , M. Debernardi , C. Pagani

Harmonic maps from Riemann surfaces arise from a conformally invariant variational problem. Therefore, on one hand, they are intimately connected with moduli spaces of Riemann surfaces, and on the other hand, because the conformal group is…

Differential Geometry · Mathematics 2017-10-05 Jürgen Jost , Enno Keßler , Jürgen Tolksdorf , Ruijun Wu , Miaomiao Zhu

We investigate a quantum geometric space in the context of what could be considered an emerging effective theory from Quantum Gravity. Specifically we consider a two-parameter class of twisted Poincar\'e algebras, from which Lie-algebraic…

Mathematical Physics · Physics 2017-05-26 Cesar A. Aguillón , Albert Much , Marcos Rosenbaum , J. David Vergara

The aim of this article is to describe a class of *-algebras that allows to treat well-behaved algebras of unbounded operators independently of a representation. To this end, Archimedean ordered *-algebras (*-algebras whose real linear…

Operator Algebras · Mathematics 2021-08-20 Matthias Schötz

We recast basic topological concepts underlying differential geometry using the language and tools of noncommutative geometry. This way we characterize principal (free and proper) actions by a density condition in (multiplier) C*-algebras.…

Differential Geometry · Mathematics 2007-05-23 Paul F. Baum , Piotr M. Hajac , Rainer Matthes , Wojciech Szymanski

There are introduced and studied a pair of associated Schouten-van Kampen affine connections adapted to the paracontact distribution and an almost paracontact almost paracomplex Riemannian structure generated by the pair of associated…

Differential Geometry · Mathematics 2021-05-21 Hristo Manev , Mancho Manev

Hilbert(ian) A-modules over finite von Neumann algebras A with a faithful normal trace state (from global analysis) and Hilbert W*-modules over A (from operator algebra theory) are compared, and a categorical equivalence is established. The…

Operator Algebras · Mathematics 2025-05-08 Michael Frank

Extending a recently proposed procedure of construction of various elements of diffential geometry on noncommutative algebras, we obtain these structures on noncommutative superalgebras. As an example, a quantum superspace covariant under…

Quantum Algebra · Mathematics 2007-05-23 N. Aizawa , R. Chakrabarti

The sectional nonassociativity of a metrized (not necessarily associative or unital) algebra is defined analogously to the sectional curvature of a pseudo-Riemannian metric, with the associator in place of the Levi-Civita covariant…

Rings and Algebras · Mathematics 2024-01-19 Daniel J. F. Fox

A shape invariant nonseparable and nondiagonalizable three-dimensional model with quadratic complex interaction was introduced by Bardavelidze, Cannata, Ioffe, and Nishnianidze. However, the complete hidden symmetry algebra and the…

Mathematical Physics · Physics 2022-01-17 Ian Marquette , Christiane Quesne

We study hermitian structures, with respect to the standard neutral metric on the cotangent bundle $T^*G$ of a 2n-dimensional Lie group $G$, which are left invariant with respect to the Lie group structure on $T^*G$ induced by the coadjoint…

Differential Geometry · Mathematics 2008-04-30 L. C. de Andrés , M. L. Barberis , I. Dotti , M. Fernández

Supersymmetric quantum mechanics is constructed in a new non-Hermitian representation. Firstly, the map between the partner operators $H^{(\pm)}$ is chosen antilinear. Secondly, both these components of a super-Hamiltonian ${\cal H}$ are…

Mathematical Physics · Physics 2015-05-13 Miloslav Znojil , Vit Jakubsky

The $tt^*$ equations define a flat connection on the moduli spaces of $2d, \mathcal{N}=2$ quantum field theories. For conformal theories with $c=3d$, which can be realized as nonlinear sigma models into Calabi-Yau d-folds, this flat…

High Energy Physics - Theory · Physics 2014-12-12 Murad Alim

Let $\mathbb{G}$ be a locally compact quantum group, and $A,B$ von Neumann algebras on which $\mathbb{G}$ acts. We refer to these as $\mathbb{G}$-dynamical W$^*$-algebras. We make a study of $\mathbb{G}$-equivariant $A$-$B$-correspondences,…

Operator Algebras · Mathematics 2024-09-19 K. De Commer , J. De Ro

We investigate the kinetics of a nonrelativistic particle interacting with a constant external force on a Lie-algebraic noncommutative space. The structure constants of a Lie algebra, also called noncommutative parameters, are constrained…

Mathematical Physics · Physics 2011-07-08 Yan-Gang Miao , Xu-Dong Wang , Shao-Jie Yu

We introduce a class of hermitian metrics with {\em Lee potential}, that generalize the notion of l.c.K. metrics with potential introduced in \cite{ov} and show that in the classical examples of Calabi and Eckmann of complex structures on…

Differential Geometry · Mathematics 2012-08-22 Florin Belgun

If two compact quantum metric spaces are close in the metric sense, then how similar are they, as noncommutative spaces? In the classical realm of Riemannian geometry, informally, if two manifolds are close in the Gromov-Hausdorff distance,…

Operator Algebras · Mathematics 2025-10-16 Carla Farsi , Frederic Latremoliere

Pseudo-Riemannian metrics with Levi-Civita connection in the projective class of a given torsion free affine connection can be obtained from (and are equivalent to) the maximal rank solutions of a certain overdetermined projectively…

Differential Geometry · Mathematics 2018-03-05 Keegan J. Flood , A. Rod Gover

A differential calculus on Cuntz algebra with three generators coming from the action of rotation group in three dimensions is introduced. The differential calculus is shown to satisfy Assumptions I-IV of [1] so that Levi-Civita Connection…

Operator Algebras · Mathematics 2019-10-01 Soumalya Joardar