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In this paper, using the recently discovered notion of the $S$-spectrum, we prove the spectral theorem for a bounded or unbounded normal operator on a Clifford module (i.e., a two-sided Hilbert module over a Clifford algebra based on units…

Functional Analysis · Mathematics 2021-12-13 Fabrizio Colombo , David P. Kimsey

We prove that on a compact $n$-dimensional spin manifold admitting a non-trivial harmonic 1-form of constant length, every eigenvalue $\lambda$ of the Dirac operator satisfies the inequality $\lambda^2 \geq \frac{n-1}{4(n-2)}\inf_M Scal$.…

Differential Geometry · Mathematics 2019-01-08 Andrei Moroianu , Liviu Ornea

In this paper, for an even dimensional compact manifold with boundary which has the non-product metric near the boundary, we use the noncommutative residue to define a conformal invariant pair. For a 4-dimensional manifold, we compute this…

Differential Geometry · Mathematics 2009-11-11 Yong Wang

Following ideas of Connes and Moscovici, we describe two spectral triples related to the Kronecker foliation, whose generalized Dirac operators are related to first and second order signature operators. We also consider the corresponding…

Mathematical Physics · Physics 2009-11-07 R. Matthes , O. Richter , G. Rudolph

We consider the algebra $A$ of bounded operators on $L^2(\mathbb{R}^n)$ generated by quantizations of isometric affine canonical transformations. The algebra $A$ includes as subalgebras all noncommutative tori and toric orbifolds. We define…

Operator Algebras · Mathematics 2022-08-04 Anton Savin , Elmar Schrohe

We compute conformal correlation functions with spinor, tensor, and spinor-tensor primary fields in general dimensions with Euclidean and Lorentzian metrics. The spinors are taken to be Dirac spinors, which exist for any dimensions. For…

High Energy Physics - Theory · Physics 2019-07-16 Hiroshi Isono

An analogue of a spectral triple over SUq(2) is constructed for which the usual assumption of bounded commutators with the Dirac operator fails. An analytic expression analogous to that for the Hochschild class of the Chern character for…

Operator Algebras · Mathematics 2011-05-27 Ulrich Kraehmer , Adam Rennie , Roger Senior

In this paper, the spectrum, residual spectrum, point spectrum and spectral radius of weighted conditional type operators are computed. As an application, we give an equivalent condition for weighted conditional type operators to be…

Functional Analysis · Mathematics 2013-10-09 Yousef Estaremi

We derive a number of spectral results for Dirac operators in geometrically nontrivial regions in $\mathbb{R}^2$ and $\mathbb{R}^3$ of tube or layer shapes with a zigzag type boundary using the corresponding properties of the Dirichlet…

Spectral Theory · Mathematics 2022-10-26 Pavel Exner , Markus Holzmann

We introduce a functional that couples the nonlinear sigma model with a spinor field: $L=\int_M[|d\phi|^2+(\psi,\D\psi)]$. In two dimensions, it is conformally invariant. The critical points of this functional are called Dirac-harmonic…

Differential Geometry · Mathematics 2007-05-23 Qun Chen , Juergen Jost , Jiayu Li , Guofang Wang

In this paper we present a complete spectral analysis of Dirac operators with non-Hermitian matrix potentials of the form $i\operatorname{sgn}(x)+V(x)$ where $V\in L^1$. For $V=0$ we compute explicitly the matrix Green function. This allows…

Spectral Theory · Mathematics 2025-04-09 Lyonell Boulton , David Krejcirik , Tho Nguyen Duc

Almost commutative models provide a framework for Connes' work on the standard model of particle physics. These models are constructed as products of a the canonical spectral triple of a compact connected spin manifold with a finite…

Operator Algebras · Mathematics 2026-03-20 Frederic Latremoliere

We show that for generic Riemannian metrics on a simply-connected closed spin manifold of dimension at least 5 the dimension of the space of harmonic spinors is no larger than it must be by the index theorem. The same result holds for…

Differential Geometry · Mathematics 2011-07-22 Christian Baer , Mattias Dahl

On a compact spin manifold we study the space of Riemannian metrics for which the Dirac operator is invertible. The first main result is a surgery theorem stating that such a metric can be extended over the trace of a surgery of codimension…

Differential Geometry · Mathematics 2011-07-21 Mattias Dahl

We construct spectral triples and, in particular, Dirac operators, for the algebra of continuous functions on certain compact metric spaces. The triples are countable sums of triples where each summand is based on a curve in the space.…

Metric Geometry · Mathematics 2007-06-19 Erik Christensen , Cristina Ivan , Michel L. Lapidus

Using the Chamseddine--Connes approach of the noncommutative action on spectral triples, we show that there are no tadpoles of any order for compact spin manifolds without boundary, and also consider a case of a chiral boundary condition.…

Mathematical Physics · Physics 2011-09-28 Bruno Iochum , Cyril Levy

We construct a 1+ summable regular even spectral triple for a noncommutative torus defined by a C*-subalgebra of the Toeplitz algebra.

Quantum Algebra · Mathematics 2018-02-20 Fredy Díaz García , Elmar Wagner

We formulate a noncommutative generalization of the Ricci flow theory in the framework of spectral action approach to noncommutative geometry. Grisha Perelman's functionals are generated as commutative versions of certain spectral…

Mathematical Physics · Physics 2011-06-02 Sergiu I. Vacaru

We construct the Wightman function for symmetric traceless tensors and Dirac fermions in dS$_{d+1}$ in a coordinate and index free formalism using a $d+2$ dimensional ambient space. We expand the embedding space formalism to cover spinor…

High Energy Physics - Theory · Physics 2022-12-16 Ben Pethybridge , Vladimir Schaub

For conformal field theories in arbitrary dimensions, we introduce a method to derive the conformal blocks corresponding to the exchange of a traceless symmetric tensor appearing in four point functions of operators with spin. Using the…

High Energy Physics - Theory · Physics 2014-07-31 Miguel S. Costa , Joao Penedones , David Poland , Slava Rychkov
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