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In this note we present some properties of the Dirac operator on noncompact metric graphs with Kirchoff-type vertex conditions. In particular, we discuss the specific features of the spectrum of the operator and, finally, we give some…

Analysis of PDEs · Mathematics 2021-02-08 William Borrelli , Raffaele Carlone , Lorenzo Tentarelli

It is shown that the square of the Dirac Hamiltonian with the isotropic mass-hedgehog potential in d dimensions is the number operator of fictitious bosons and fermions over d quantum states. This result allows one to obtain the complete…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 Igor F. Herbut , Chi-Ken Lu

We study three practical implementations of the Overlap-Dirac operator $D_o= (1/2) [1 + \gamma_5\epsilon(H_w)]$ in four dimensions. Two implementations are based on different representations of $\epsilon(H_w)$ as a sum over poles. One of…

High Energy Physics - Lattice · Physics 2011-07-19 Robert G. Edwards , Urs M. Heller , Rajamani Narayanan

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

We construct a Connes spectral triple or `Dirac operator' on the non-reduced fuzzy sphere $C_\lambda[S^2]$ as realised using quantum Riemannian geometry with a central quantum metric $g$ of Euclidean signature and its associated quantum…

Quantum Algebra · Mathematics 2022-02-09 Evelyn Lira-Torres , Shahn Majid

We derive bounds on the location of non-embedded eigenvalues of Dirac operators on the half-line with non-Hermitian $L^1$-potentials. The results are sharp in the non-relativistic or weak-coupling limit. In the massless case, the absence of…

Spectral Theory · Mathematics 2013-11-27 Jean-Claude Cuenin

We investigate the leading terms of the spectral action for odd-dimensional Riemannian spin manifolds with the Dirac operator perturbed by a scalar function. We calculate first two Gilkey-de Witt coefficients and make explicit calculations…

Mathematical Physics · Physics 2015-05-20 Andrzej Sitarz , Artur Zajac

The Dirac-Dolbeault operator for a compact K\"ahler manifold is a special case of a Dirac operator. The Green function for the Dirac Laplacian over a Riemannian manifold with boundary allows to express the values of the sections of the…

Differential Geometry · Mathematics 2024-07-15 Simone Farinelli

We investigate the existence of discrete positive or negative energy ground states of the Dirac operator $H$ which describe the fermion scattering on topological solitons in the nonlinear $O(3)$ $\sigma$-model. Additionally, we provide a…

Mathematical Physics · Physics 2025-03-13 Daiju Funakawa , Satoshi Okumura , Yuki Ueda

We define Dirac operators on $\mathbb{S}^3$ (and $\mathbb{R}^3$) with magnetic fields supported on smooth, oriented links and prove self-adjointness of certain (natural) extensions. We then analyze their spectral properties and show, among…

Mathematical Physics · Physics 2018-02-21 Fabian Portmann , Jérémy Sok , Jan Philip Solovej

We prove quadratic estimates for complex perturbations of Dirac-type operators, and thereby show that such operators have a bounded functional calculus. As an application we show that spectral projections of the Hodge--Dirac operator on…

Spectral Theory · Mathematics 2009-11-10 Andreas Axelsson , Stephen Keith , Alan McIntosh

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

We compute the spectrum of color-singlet fermionic operators in the N=2 gauge theory on intersecting D3 and D7-branes using the AdS/CFT correspondence. The operator spectrum is found analytically by solving the equations for the dual…

High Energy Physics - Theory · Physics 2009-11-11 Ingo Kirsch

Let M be a closed spin manifold of dimension at least three with a fixed topological spin structure. For any Riemannian metric, we can construct the associated Dirac operator. The spectrum of this Dirac operator depends on the metric of…

Differential Geometry · Mathematics 2015-01-19 Nikolai Nowaczyk

A version of the Dirac equation is derived from first principles using a combination of quaternions and multivariate 4-vectors. The nilpotent form of the operators used allows us to derive explicit expressions for the wavefunctions of free…

Quantum Physics · Physics 2007-05-23 Peter Rowlands , John P. Cullerne

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

We show that the first five of the axioms we had formulated on spectral triples suffice (in a slightly stronger form) to characterize the spectral triples associated to smooth compact manifolds. The algebra, which is assumed to be…

Operator Algebras · Mathematics 2008-10-14 Alain Connes

It is shown that the eigenvalue problem for the hermitian Wilson-Dirac operator of for a uniform magnetic field in two dimensions can be reduced to one-dimensional problem described by a relativistic analog of the Harper equation. An…

High Energy Physics - Lattice · Physics 2009-11-07 H. Kurokawa , T. Fujiwara

We consider compact Riemannian spin manifolds without boundary equipped with orthogonal connections. We investigate the induced Dirac operators and the associated commutative spectral triples. In case of dimension four and totally…

Mathematical Physics · Physics 2011-06-06 Frank Pfaeffle , Christoph A. Stephan

It is a well-known fact that on a bounded spectral interval the Dirac spectrum can be described locally by a non-decreasing sequence of continuous functions of the Riemannian metric. In the present article we extend this result to a global…

Differential Geometry · Mathematics 2015-05-19 Nikolai Nowaczyk