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Related papers: Dirac series of U(n,2)

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Motivated by the $(\mathfrak{g},K)$-cohomology and Dirac cohomology, we determine Dirac series of $\mathrm{GL}(n,\mathbb{H})$, and show that the spin lowest $K$-type of any Dirac series, which determines the Dirac cohomology, is unique and…

Representation Theory · Mathematics 2025-06-27 Yihao Ding , Hongfeng Zhang

This paper classifies all the Dirac series (that is, irreducible unitary representations having non-zero Dirac cohomology) of $E_{7(7)}$. Enhancing the Helgason-Johnson bound in 1969 for the group $E_{7(7)}$ is one key ingredient. Our…

Representation Theory · Mathematics 2024-12-20 Yi-Hao Ding , Chao-Ping Dong , Lin Wei

Let $G$ be $Sp(2n, \mathbb{R})$ or $SO^*(2n)$. We compute the Dirac index of a large class of unitary representations considered by Vogan in Section 8 of [Vog84], which include all weakly fair $A_{\mathfrak{q}}(\lambda)$ modules and…

Representation Theory · Mathematics 2021-02-17 Chao-Ping Dong , Kayue Daniel Wong

In this paper, we classify all unitary representations with non-zero Dirac cohomology for complex Lie group of Type E8. This completes the classification of Dirac series for all complex simple Lie groups.

Representation Theory · Mathematics 2026-04-22 Dan Barbasch , Kayue Daniel Wong

Dirac operators and Dirac cohomology for Lie superalgebras of Riemannian type, introduced by Huang and Pand\v{z}i\'{c}, provide an effective tool for the study of unitarizable supermodules. In this article, we study these objects for Lie…

Representation Theory · Mathematics 2026-03-24 Steffen Schmidt

The relationship between the Dirac and reduced phase space quantizations is investigated for spin models belonging to the class of Hamiltonian systems having no gauge conditions. It is traced out that the two quantization methods may give…

High Energy Physics - Theory · Physics 2007-05-23 Mikhail S. Plyushchay , Alexander V. Razumov

This paper computes the Dirac cohomology $H_D(\pi)$ of irreducible unitary Harish-Chandra modules $\pi$ of complex classical groups viewed as real reductive groups. More precisely, unitary representations with nonzero Dirac cohomology are…

Representation Theory · Mathematics 2022-03-31 Dan Barbasch , Chao-Ping Dong , Kayue Daniel Wong

We show the existence of nonsymmetric homogeneous spin Riemannian manifolds whose Dirac operator is like that on a Riemannian symmetric spin space. Such manifolds are exactly the homogeneous spin Riemannian manifolds $(M,g)$ which are…

Differential Geometry · Mathematics 2016-02-10 P. M. Gadea , José C. González-Dávila , José A. Oubiña

We find and classify possible equivariant spin structures with Dirac operators on the noncommutative torus, proving that similarly as in the classical case the spectrum of the Dirac operator depends on the spin structure.

Quantum Algebra · Mathematics 2018-06-04 Mario Paschke , Andrzej Sitarz

The idea of using Dirac cohomology to study branching laws was initiated by Huang, Pandzi\'c and Zhu in 2013 [HPZ]. One of their results says that the Dirac cohomology of $\pi$ completely determines $\pi|_{K}$, where $\pi$ is any…

Representation Theory · Mathematics 2024-11-07 Chao-Ping Dong , Yongzhi Luan , Haojun Xu

Whatever it is that animates anima and breathes life into higher algebra, this something leaves its trace in the structure of a Dirac ring on the homotopy groups of a commutative algebra in spectra. In the prequel to this paper, we…

Algebraic Topology · Mathematics 2024-01-03 Lars Hesselholt , Piotr Pstragowski

In this paper we study the problem of computing the Dirac cohomology of the special unipotent representations of the real groups Sp(2n,R) and U(p,q).

Representation Theory · Mathematics 2013-02-20 Dan Barbasch , Pavle Pandžić

In a joint paper P. Pand\v{z}i\'c and D. Renard proved that holomorphic and antiholomorphic discrete series representations can be constructed via algebraic Dirac induction. The group $SU(2,1)$, except for those two types, also has a third…

Representation Theory · Mathematics 2016-07-05 Ana Prlić

An integer valued topological index of a Dirac operator is introduced for a pair of a 4n+2 dimensional open Spin^c manifold and a section of the determinant line bundle satisfying some property. We show a relation between the index and an…

Differential Geometry · Mathematics 2014-01-22 Shin Hayashi

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

Let $\mathfrak{g}$ be a reductive Lie algebra over $\mathbb{C}$. For any simple weight module of $\mathfrak{g}$ with finite-dimensional weight spaces, we show that its Dirac cohomology is vanished unless it is a highest weight module. This…

Representation Theory · Mathematics 2022-09-27 Jingsong Huang , Wei Xiao

The unitary dual of $GL(n, \mathbb{R})$ was classified by Vogan in the 1980s. Focusing on the irreducible unitary representations of $GL(n, \mathbb{R})$ with half-integral infinitesimal characters, we find that Speh representations and the…

Representation Theory · Mathematics 2020-07-13 Chao-Ping Dong , Kayue Daniel Wong

This paper computes the Dirac index of all the weakly fair $A_{\mathfrak{q}}(\lambda)$ modules of $U(p, q)$. Although counter-examples have been found to a conjecture of Vogan on the unitary dual of $U(p, q)$ phrased by Trapa in 2001, we…

Representation Theory · Mathematics 2020-10-15 Chao-ping Dong , Kayue Daniel Wong

Recently, several new materials exhibiting massless Dirac fermions have been proposed. However, many of these do not have the typical graphene honeycomb lattice, which is often associated with Dirac cones. Here, we present a classification…

Materials Science · Physics 2016-01-12 G. van Miert , C. Morais Smith

Up to equivalence, this paper classifies all the irreducible unitary representations with non-zero Dirac cohomology for the following simple real exceptional Lie groups: ${\rm EI}=E_{6(6)}, {\rm EIV}=E_{6(-26)}, {\rm FI}=F_{4(4)}, {\rm…

Representation Theory · Mathematics 2020-05-12 Jian Ding , Chao-Ping Dong , Liang Yang
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