Aubry-Mather theory and periodic solutions of the forced Burgers equation

✍ Scribed by Weinan E

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 377 KB
• Volume: 52
• Category: Article
• ISSN: 0010-3640
• DOI: 10.1002/(sici)1097-0312(199907)52:7<811::aid-cpa2>3.0.co;2-d

✦ Synopsis

Consider a Hamiltonian system with Hamiltonian of the form H(x, t, p) where H is convex in p and periodic in x, and t and x ∈ R 1 . It is well-known that its smooth invariant curves correspond to smooth Z 2 -periodic solutions of the PDE ut + H(x, t, u)x = 0 .

In this paper, we establish a connection between the Aubry-Mather theory of invariant sets of the Hamiltonian system and Z 2 -periodic weak solutions of this PDE by realizing the Aubry-Mather sets as closed subsets of the graphs of these weak solutions. We show that the complement of the Aubry-Mather set on the graph can be viewed as a subset of the generalized unstable manifold of the Aubry-Mather set, defined in (2.24). The graph itself is a backward-invariant set of the Hamiltonian system. The basic idea is to embed the globally minimizing orbits used in the Aubry-Mather theory into the characteristic fields of the above PDE. This is done by making use of one-and two-sided minimizers, a notion introduced in [12] and inspired by the work of Morse on geodesics of type A [26]. The asymptotic slope of the minimizers, also known as the rotation number, is given by the derivative of the homogenized Hamiltonian, defined in [21]. As an application, we prove that the Z 2 -periodic weak solution of the above PDE with given irrational asymptotic slope is unique. A similar connection also exists in multidimensional problems with the convex Hamiltonian, except that in higher dimensions, two-sided minimizers with a specified asymptotic slope may not exist.