We demonstrate lower bounds for the eigenvalues of compact Bakry-Emery manifolds with and without boundary. The lower bounds for the first eigenvalue rely on a generalised maximum principle which allows gradient estimates in the Riemannian setting to be directly applied to the Bakry-Emery setting. Lower bounds for all eigenvalues are demonstrated using heat kernel estimates and a suitable Sobolev inequality.
This article is a brief presentation of results surrounding the fundamental gap. We begin by recalling Bakry-Emery geometry and demonstrate connections between eigenvalues of the Laplacian with the Dirichlet and Neumann boundary conditions. We then s
how a connection between the fundamental gap and Bakry-Emery geometry, concluding with a presentation of the key ideas in Andrewss and Clutterbucks proof of the fundamental gap conjecture. We conclude with a presentation of results for the fundamental gap of triangles and simplices.
We consider Schroedinger operators on regular metric trees and prove Lieb-Thirring and Cwikel-Lieb-Rozenblum inequalities for their negative eigenvalues. The validity of these inequalities depends on the volume growth of the tree. We show that the bo
unds are valid in the endpoint case and reflect the correct order in the weak or strong coupling limit.
We consider a twisted quantum wave guide, and are interested in the spectral analysis of the associated Dirichlet Laplacian H. We show that if the derivative of rotation angle decays slowly enough at infinity, then there is an infinite sequence of di
screte eigenvalues lying below the infimum of the essential spectrum of H, and obtain the main asymptotic term of this sequence.
We prove various estimates for the first eigenvalue of the magnetic Dirichlet Laplacian on a bounded domain in two dimensions. When the magnetic field is constant, we give lower and upper bounds in terms of geometric quantities of the domain. We furt
hermore prove a lower bound for the first magnetic Neumann eigenvalue in the case of constant field.
We present a brief survey of the spectral theory and dynamics of infinite volume asymptotically hyperbolic manifolds. Beginning with their geometry and examples, we proceed to their spectral and scattering theories, dynamics, and the physical descrip
tion of their quantum and classical mechanics. We conclude with a discussion of recent results, ideas, and conjectures.