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The physical concept of locality is first analyzed in the special relativistic quantum regime, and compared with that of microcausality and the local commutativity of quantum fields. Its extrapolation to quantum general relativity on…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Eduard Prugovecki

On a locally compact group we introduce covariant quantization schemes and analogs of phase space representations as well as mixed-state localization operators. These generalize corresponding notions for the affine group and the Heisenberg…

Functional Analysis · Mathematics 2023-07-20 Simon Halvdansson

We propose a definition of a quantum homogeneous space of a locally compact quantum group. We show that classically it reduces to the notion of a homogeneous spaces. On the quantum level our definition goes beyond the quotient case. It…

Operator Algebras · Mathematics 2014-10-30 Pawel Kasprzak

We provide a new characterisation of quantum supermaps in terms of an axiom that refers only to sequential and parallel composition. Consequently, we generalize quantum supermaps to arbitrary monoidal categories and operational…

Quantum Physics · Physics 2026-03-11 Matt Wilson , Giulio Chiribella , Aleks Kissinger

A notion of a quantum automorphism group of a finite quantum group, generalising that of a classical automorphism group of a finite group, is proposed and a corresponding existence result proved.

Operator Algebras · Mathematics 2014-10-28 Jyotishman Bhowmick , Adam Skalski , Piotr M. Sołtan

We study the action of space-time symmetries on quantum fields in the presence of small departures from locality determined by dynamical gravity. It is shown that, under such relaxation of locality, the symmetries of the theory cannot be…

High Energy Physics - Theory · Physics 2008-11-26 Michele Arzano

Using methods coming from non-formal equivariant quantization, we construct in this short note a unitary dual 2-cocycle on a discrete family of quotient groups of subgroups of the affine group of a local field (which is not of…

Operator Algebras · Mathematics 2018-09-26 David Jondreville

Starting from any proper action of any locally compact quantum group on any discrete quantum space, we show that its equivariant representation theory yields a concrete unitary 2-category of finite type Hilbert bimodules over the discrete…

Operator Algebras · Mathematics 2025-08-27 Lukas Rollier

To any action of a compact quantum group on a von Neumann algebra which is a direct sum of factors we associate an equivalence relation corresponding to the partition of a space into orbits of the action. We show that in case all factors…

Operator Algebras · Mathematics 2019-01-29 Kenny De Commer , Paweł Kasprzak , Adam Skalski , Piotr M. Sołtan

A class of negative definite kernels is defined in terms of measure spaces. Using this concept, property (T) for a countable group $\G$ is characterized in terms of measure preserving actions of $\G$, as follows. If a set $S$ is translated…

Functional Analysis · Mathematics 2013-02-26 Guyan Robertson , Tim Steger

Convex sets of completely positive maps and positive semidefinite kernels are considered in the most general context of modules over $C^*$-algebras and a complete charaterization of their extreme points is obtained. As a byproduct, we…

Quantum Physics · Physics 2014-03-05 Juha-Pekka Pellonpää

For a broad class of Frechet-Lie supergroups we prove that there exists a correspondence between positive definite smooth superfunctions and matrix coefficients of unitary representations. We also give a characterization of linear…

Representation Theory · Mathematics 2012-08-14 Karl-Hermann Neeb , Hadi Salmasian

Building on the "quantum inequalities" introduced by Ford, I argue that the negative local energies encountered in quantum field theory can only be observed by detectors with positive energies at least as great in magnitude. This means that…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Adam D. Helfer

We show that either of the two reasonable choices for the category of compact quantum groups is nice enough to allow for a plethora of universal constructions, all obtained "by abstract nonsense" via the adjoint functor theorem. This…

Quantum Algebra · Mathematics 2012-08-28 Alexandru Chirvasitu

We consider a kernel based harmonic analysis of "boundary," and boundary representations. Our setting is general: certain classes of positive definite kernels. Our theorems extend (and are motivated by) results and notions from classical…

Functional Analysis · Mathematics 2016-11-15 Palle Jorgensen , Feng Tian

The main result of the paper is the characterization of those locally compact quantum groups with projection, i.e. non-commutative analogs of semidirect products, which are extensions as defined by L. Vainerman and S. Vaes. It turns out…

Operator Algebras · Mathematics 2017-01-17 P. Kasprzak , P. M. Sołtan

We introduce quantum tomography on locally compact Abelian groups $G$. A linear map from the set of quantum states on the $C^*$-algebra $A(G)$ generated by the projective unitary representation of $G$ to the space of characteristic…

Quantum Physics · Physics 2022-05-26 Grigori Amosov

We introduce the notion of Dunkl positive definite and strictly positive definite functions on $\mathbb{R}^{d}$. This done by the use of the properties of Dunkl translation. We establish the analogue of Bochner's theorem in Dunkl setting.…

Classical Analysis and ODEs · Mathematics 2013-06-04 Jamel El Kamel , Khaled Mehrez

This paper has two goals: to present some new results that are necessary for further study and applications of quasi-linear functionals, and, by combining known and new results, to serve as a convenient single source for anyone interested…

Functional Analysis · Mathematics 2019-02-12 Svetlana V. Butler

The principle of local covariance which was recently introduced admits a generally covariant formulation of quantum field theory. It allows a discussion of structural properties of quantum field theory as well as the perturbative…

High Energy Physics - Theory · Physics 2007-05-23 Klaus Fredenhagen