{ "id": "1801.04109", "version": "v1", "published": "2018-01-12T09:48:17.000Z", "updated": "2018-01-12T09:48:17.000Z", "title": "Couplings in L^p distance of two Brownian motions and their L{é}vy area", "authors": [ "Michel Bonnefont", "Nicolas Juillet" ], "categories": [ "math.PR" ], "abstract": "We study co-adapted couplings of (canonical hypoelliptic) diffu-sions on the (subRiemannian) Heisenberg group, that we call (Heisenberg) Brow-nian motions and are the joint laws of a planar Brownian motion with its L{\\'e}vy area. We show that contrary to the situation observed on Riemannian manifolds of non-negative Ricci curvature, for any co-adapted coupling, two Heisenberg Brownian motions starting at two given points can not stay at bounded distance for all time t $\\ge$ 0. Actually, we prove the stronger result that they can not stay bounded in L p for p $\\ge$ 2. We also study the coupling by reflection, and show that it stays bounded in L p for 0 $\\le$ p < 1. Finally, we explain how the results generalise to the Heisenberg groups of higher dimension", "revisions": [ { "version": "v1", "updated": "2018-01-12T09:48:17.000Z" } ], "analyses": { "keywords": [ "vy area", "heisenberg group", "planar brownian motion", "study co-adapted couplings", "brow-nian motions" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }