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The tempered representations of a real reductive Lie group $G$ are naturally partitioned into series associated with conjugacy classes of Cartan subgroups $H$ of $G$. We define partial Dirac cohomology, apply it for geometric construction…

Representation Theory · Mathematics 2022-02-15 Meng-Kiat Chuah , Jing-Song Huang , Joseph A. Wolf

The Lie algebra $\mathcal{D}$ of regular differential operators on the circle has a universal central extension $\hat{\mathcal{D}}$. The invariant subalgebra $\hat{\mathcal{D}}^+$ under an involution preserving the principal gradation was…

Representation Theory · Mathematics 2020-08-10 Andrew R. Linshaw

We modify the construction of the spectral triple over an algebra of holonomy loops by introducing additional parameters in form of families of matrices. These matrices generalize the already constructed Euler-Dirac type operator over a…

High Energy Physics - Theory · Physics 2009-11-16 Johannes Aastrup , Jesper M. Grimstrup , Mario Paschke

We investigate examples of quasi-spectral triples over two-dimensional commutative sphere, which are obtained by modifying the order-one condition. We find equivariant quasi-Dirac operators and prove that they are in a topologically…

Mathematical Physics · Physics 2018-06-04 Andrzej Sitarz

In the Schrodinger picture of the Dirac quantum mechanics, defined in charts with spatially flat Robertson-Walker metrics and Cartesian coordinates the perturbation theory is applied to the interacting part of the Hamiltonian operator…

General Relativity and Quantum Cosmology · Physics 2007-11-28 Pop Adrian Alin

As is known, the so-called Dirac $K$-operator commutes with the Dirac Hamiltonian for arbitrary central potential $V(r)$. Therefore the spectrum is degenerate with respect to two signs of its eigenvalues. This degeneracy may be described by…

High Energy Physics - Theory · Physics 2009-01-16 Tamari~T. Khachidze , Anzor~A. Khelashvili

Let $Q$ be a differential operator of order $\leq 1$ on a complex metric vector bundle $\mathscr{E}\to \mathscr{M}$ with metric connection $\nabla$ over a possibly noncompact Riemannian manifold $\mathscr{M}$. Under very mild regularity…

Mathematical Physics · Physics 2022-08-30 Sebastian Boldt , Batu Güneysu

We study the decomposition into irreducibles of the kernel of noncubic Dirac operators attached to finite-dimensional modules. We compare this decomposition with features of Kostant's cubic Dirac operator. In particular, we show that the…

Representation Theory · Mathematics 2022-09-27 Spyridon Afentoulidis-Almpanis

By a result of Nagy, the C*-algebra of continuous functions on the q-deformation G_q of a simply connected semisimple compact Lie group G is KK-equivalent to C(G). We show that under this equivalence the K-homology class of the Dirac…

Operator Algebras · Mathematics 2011-02-02 Sergey Neshveyev , Lars Tuset

We define uniformly the notions of Dirac operators and Dirac cohomology in the framework of the Hecke algebras introduced by Drinfeld. We generalize in this way the Dirac cohomology theory for Lusztig's graded affine Hecke algebras. We…

Representation Theory · Mathematics 2015-06-23 Dan Ciubotaru

We introduce a Dirac operator $D$ for the quantum group $U_q(\mathfrak{sl}_2)$, as an element of the tensor product of $U_q(\mathfrak{sl}_2)$ with the Clifford algebra on two generators. We study the properties of $D$, including an analogue…

Representation Theory · Mathematics 2017-04-26 Pavle Pandžić , Petr Somberg

In 1993, Lian-Zuckerman constructed two cohomology operations on the BRST complex of a conformal vertex algebra with central charge 26. They gave explicit generators and relations for the cohomology algebra equipped with these operations in…

Quantum Algebra · Mathematics 2009-11-11 Andrew R. Linshaw

We define a class of algebras which are distinguished by a PBW property and an orthogonality condition, and which we call Hopf-Hecke algebras, since they generalize the Drinfeld Hecke algebras defined by Drinfeld. In the course of studying…

Representation Theory · Mathematics 2016-09-07 Johannes Flake

Using a super-affine version of Kostant's cubic Dirac operator, we prove a very strange formula for quadratic finite-dimensional Lie superalgebras with a reductive even subalgebra.

Representation Theory · Mathematics 2017-01-23 Victor G. Kac , Pierluigi Moseneder Frajria , Paolo Papi

For the q-deformation G_q, 0<q<1, of any simply connected simple compact Lie group G we construct an equivariant spectral triple which is an isospectral deformation of that defined by the Dirac operator D on G. Our quantum Dirac operator…

Operator Algebras · Mathematics 2007-05-23 Sergey Neshveyev , Lars Tuset

Motivated by the supersymmetric version of Dirac's theory, chiral models in field theory, and the quest of a geometric fundament for the Standard Model, we describe an approach to the differential geometry of vector bundles on…

Mathematical Physics · Physics 2007-05-23 G. Roepstorff , Ch. Vehns

In \cite{BKN} the authors initiated a study of the representation theory of classical Lie superalgebras via a cohomological approach. Detecting subalgebras were constructed and a theory of support varieties was developed. The dimension of a…

Representation Theory · Mathematics 2014-02-26 Brian D. Boe , Jonathan R. Kujawa , Daniel K. Nakano

Twisted K-theory classes over compact Lie groups can be realized as families of Fredholm operators using the representation theory of loop groups. In this talk I want to show how to deform the Fredholm family, in the sense of quantum…

K-Theory and Homology · Mathematics 2010-08-20 Jouko Mickelsson

The quantum weighted projective algebras $\mathbb{C}[\mathbb{WP}_{k,l,q}]$ are coinvariant subalgebras of the quantum group algebra $\mathbb{C}[SU_{q,2}]$. For each pair of indices $k,l$, two $2$-summable spectral triples will be…

Quantum Algebra · Mathematics 2015-04-07 Antti J. Harju

In this paper we set-up a general framework for a formal deformation theory of Dirac structures. We give a parameterization of formal deformations in terms of two-forms obeying a cubic equation. The notion of equivalence is discussed in…

Quantum Algebra · Mathematics 2009-11-11 Frank Keller , Stefan Waldmann