{ "id": "1807.00219", "version": "v1", "published": "2018-06-30T19:33:02.000Z", "updated": "2018-06-30T19:33:02.000Z", "title": "The Massless Dirac Equation in Two Dimensions: Zero-Energy Obstructions and Dispersive Estimates", "authors": [ "Burak Erdogan", "Michael Goldberg", "William R. Green" ], "comment": "37 pages, submitted", "categories": [ "math.AP", "math-ph", "math.MP" ], "abstract": "We investigate $L^1\\to L^\\infty$ dispersive estimates for the massless two dimensional Dirac equation with a potential. In particular, we show that the Dirac evolution satisfies the natural $t^{-\\frac12}$ decay rate, which may be improved to $t^{-\\frac12-\\gamma}$ for any $0\\leq \\gamma<\\frac{3}{2}$ at the cost of spatial weights. We classify the structure of threshold obstructions as being composed of a two dimensional space of p-wave resonances and a finite dimensional space of eigenfunctions at zero energy. We show that, in the presence of a threshold resonance, the Dirac evolution satisfies the natural decay rate except for a finite-rank piece. While in the case of a threshold eigenvalue only, the natural decay rate is preserved. In both cases we show that the decay rate may be improved at the cost of spatial weights.", "revisions": [ { "version": "v1", "updated": "2018-06-30T19:33:02.000Z" } ], "analyses": { "keywords": [ "massless dirac equation", "dispersive estimates", "zero-energy obstructions", "natural decay rate", "dirac evolution satisfies" ], "note": { "typesetting": "TeX", "pages": 37, "language": "en", "license": "arXiv", "status": "editable" } } }