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We construct relativistic quantum Markov semigroups from covariant completely positive maps. We proceed by generalizing a step in Stinespring's dilation to a general system of imprimitivity and basing it on Poincar\'e group. The resulting…

Quantum Physics · Physics 2021-02-22 Radhakrishnan Balu

For a closed subset $K$ of a compact metric space $A$ possessing an $\alpha$-regular measure $\mu$ with $\mu(K)>0$, we prove that whenever $s>\alpha$, any sequence of weighted minimal Riesz $s$-energy configurations…

Mathematical Physics · Physics 2011-11-23 D. P. Hardin , E. B. Saff , J. T. Whitehouse

Relativistic continuous matrix product states (RCMPS) are a powerful variational ansatz for quantum field theories of a single field. However, they inherit a property of their non-relativistic counterpart that makes them divergent for…

Quantum Physics · Physics 2025-11-27 Karan Tiwana , Antoine Tilloy

We consider Riesz transforms of any order associated to an Ornstein--Uhlenbeck operator $\mathcal L$, with covariance $Q$ given by a real, symmetric and positive definite matrix, and with drift $B$ given by a real matrix whose eigenvalues…

Functional Analysis · Mathematics 2021-09-29 Valentina Casarino , Paolo Ciatti , Peter Sjögren

In this paper the space of almost commuting elements in a Lie group is studied through a homotopical point of view. In particular a stable splitting after one suspension is derived for these spaces and their quotients under conjugation. A…

Algebraic Topology · Mathematics 2015-05-20 Alejandro Adem , Frederick R. Cohen , Jose Manuel Gomez

We prove several rigidity properties for random quotients of mapping class groups of surfaces, namely whose kernel is normally generated by the n-th steps of finitely many independent random walks. Firstly, we generalise a celebrated…

Group Theory · Mathematics 2025-08-18 Giorgio Mangioni

Two groups are virtually isomorphic if they can be obtained one from the other via a finite number of steps, where each step consists in taking a finite extension or a finite index subgroup (or viceversa). Virtually isomorphic groups are…

Geometric Topology · Mathematics 2016-02-15 Roberto Frigerio

We provide a study of the Riesz transforms on stratified nilpotent Lie groups, and obtain a certain version of the pointwise lower bound of the Riesz transform kernel. Then we establish the characterisation of the BMO space on stratified…

Classical Analysis and ODEs · Mathematics 2018-03-06 Xuan Thinh Duong , Hong-Quan Li , Ji Li , Brett D. Wick

If a compact quantum group acts faithfully and smoothly (in the sense of Goswami 2009) on a smooth, compact, oriented, connected Riemannian manifold such that the action induces a natural bimodule morphism on the module of sections of the…

Operator Algebras · Mathematics 2014-11-17 Debashish Goswami

A continuous groupoid homomorphism $c$ on a locally compact second countable Hausdorff \'etale groupoid $\mathcal{G}$ gives rise to a $C^{*}$-dynamical system in which every $\beta$-KMS state can be associated to a $e^{-\beta…

Operator Algebras · Mathematics 2018-10-17 Johannes Christensen

In deformation-rigidity theory it is often important to know whether certain bimodules are weakly contained in the coarse bimodule. Consider a bimodule $H$ over the group algebra $\mathbb{C}[\Gamma]$, with $\Gamma$ a discrete group. The…

Operator Algebras · Mathematics 2024-09-11 Matthijs Borst , Martijn Caspers , Mateusz Wasilewski

We prove two results. (1) There is an absolute constant $D$ such that for any finite quasisimple group $S$, given 2D arbitrary automorphisms of $S$, every element of $S$ is equal to a product of $D$ `twisted commutators' defined by the…

Group Theory · Mathematics 2007-05-23 Nikolay Nikolov , Dan Segal

A locally compact groupoid is said to be exact if its associated reduced crossed product functor is exact. In this paper, we establish some permanence properties of exactness, including generalizations of some known results for exact…

Operator Algebras · Mathematics 2018-11-07 Scott M. LaLonde

We study the Haagerup--Kraus approximation property for locally compact quantum groups, generalising and unifying previous work by Kraus--Ruan and Crann. Along the way we discuss how multipliers of quantum groups interact with the…

Operator Algebras · Mathematics 2024-01-05 Matthew Daws , Jacek Krajczok , Christian Voigt

We introduce an equivariant version of the Cuntz semigroup, that takes an action of a compact group into account. The equivariant Cuntz semigroup is naturally a semimodule over the representation semiring of the given group. Moreover, this…

Operator Algebras · Mathematics 2018-01-08 Eusebio Gardella , Luis Santiago

We prove the existence of a quantum isometry groups for new classes of metric spaces: (i) geodesic metrics for compact connected Riemannian manifolds (possibly with boundary) and (ii) metric spaces admitting a uniformly distributed…

Quantum Algebra · Mathematics 2020-10-28 Alexandru Chirvasitu , Debashish Goswami

We investigate Fourier multipliers on the compact dual of arbitrary discrete groups. Our main result is a H\"ormander-Mihlin multiplier theorem for finite-dimensional cocycles with optimal smoothness condition. We also find Littlewood-Paley…

Classical Analysis and ODEs · Mathematics 2014-10-07 Marius Junge , Tao Mei , Javier Parcet

Almost-isometries are quasi-isometries with multiplicative constant one. Lifting a pair of metrics on a compact space gives quasi-isometric metrics on the universal cover. Under some additional hypotheses on the metrics, we show that there…

Group Theory · Mathematics 2016-07-19 Aditi Kar , Jean-Francois Lafont , Benjamin Schmidt

Let $\Gamma$ be a countable group acting on a countable set $X$ by permutations. We give a necessary and sufficient condition for the action to have a quasi-invariant mean with a given cocycle. This can be viewed as a combinatorial analogue…

Functional Analysis · Mathematics 2011-10-11 Gabor Elek , Adam Timar

We show that the orthogonal free quantum groups are not inner amenable and we construct an explicit proper cocycle weakly contained in the regular representation. This strengthens the result of Vaes and the second author, showing that the…

Operator Algebras · Mathematics 2016-12-06 Pierre Fima , Roland Vergnioux