Abstract:We consider the classical Dirac operator on globally hyperbolic manifolds with timelike boundary and show well-posedness of the Cauchy initial-boundary value problem coupled to APS-boundary conditions. This is achieved by deriving suitable energy estimates, which play a fundamental role in establishing uniqueness and existence of weak solutions. Finally, by introducing suitable mollifier operators, we study the differentiability of the solutions. For obtaining smoothness we need additional technical conditions. Show more
“…On the side note we remark that if the boundary is assumed to be time-like instead of being space-like, the Lorentzian Dirac operator behaves very differently, see Drago-Große-Murro for the well-posedness of the corresponding Cauchy problem [26] Finally, as our result assumes compactness of M in spatial directions, one might ask if an index formula could be shown for e.g. perturbations of Minkowski space and other classes of non-compact spacetimes.…”
We consider the Dirac operator on asymptotically static Lorentzian manifolds with an odd-dimensional compact Cauchy surface. We prove that if Atiyah-Patodi-Singer boundary conditions are imposed at infinite times then the Dirac operator is Fredholm. This generalizes a theorem due to in the case of finite times, and we also show that the corresponding index formula extends to the infinite setting. Furthermore, we demonstrate the existence of a Fredholm inverse which is at the same time a Feynman parametrix in the sense of Duistermaat-Hörmander. The proof combines methods from time-dependent scattering theory with a variant of Egorov's theorem for pseudo-differential hyperbolic systems.
“…On the side note we remark that if the boundary is assumed to be time-like instead of being space-like, the Lorentzian Dirac operator behaves very differently, see Drago-Große-Murro for the well-posedness of the corresponding Cauchy problem [26] Finally, as our result assumes compactness of M in spatial directions, one might ask if an index formula could be shown for e.g. perturbations of Minkowski space and other classes of non-compact spacetimes.…”
We consider the Dirac operator on asymptotically static Lorentzian manifolds with an odd-dimensional compact Cauchy surface. We prove that if Atiyah-Patodi-Singer boundary conditions are imposed at infinite times then the Dirac operator is Fredholm. This generalizes a theorem due to in the case of finite times, and we also show that the corresponding index formula extends to the infinite setting. Furthermore, we demonstrate the existence of a Fredholm inverse which is at the same time a Feynman parametrix in the sense of Duistermaat-Hörmander. The proof combines methods from time-dependent scattering theory with a variant of Egorov's theorem for pseudo-differential hyperbolic systems.
“…Let us remark that not all physical interesting boundary conditions for Dirac fields enter in this class of boundary condition. Indeed there exists physically interesting non-local boundary conditions, like the so-called APS boundary condition, which guarantees that the Cauchy problem is well-posed [37], but they are not admissible (since any admissible boundary condition is a local condition). For further details on self-adjoint admissible boundary conditions for the Dirac fields we refer to [52, Section 6.1.1] and [53,Remark 3.19].…”
The aim of this paper is to prove the existence of Hadamard states for Dirac fields coupled with MIT boundary conditions on any globally hyperbolic manifold with timelike boundary. This is achieved by introducing a geometric Møller operator which implements a unitary isomorphism between the spaces of L 2 -initial data of particular symmetric systems we call weakly-hyperbolic and which are coupled with admissible boundary conditions. In particular, we show that for Dirac fields with MIT boundary conditions, this isomorphism can be lifted to a * -isomorphism between the algebras of Dirac fields and that any Hadamard state can be pulled back along this * -isomorphism preserving the singular structure of its two-point distribution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.