Abstract.We check that several properties of the Aubry set, first proven for finite-dimensional Lagrangians by Mather and Fathi, continue to hold in the case of the infinitely many interacting particles of the Vlasov equation on the circle. Mathematics Subject Classification. Primary 37J50; Secondary 35Q83. Keywords. Vlasov equation, Aubry-Mather theory.
IntroductionThe Vlasov equation on the circle governs the motion of a group of particles on S 1 := R Z under the action of an external potential V (t, x) and a mutual interaction W . More precisely, we let I = [0, 1), we lift our particles to R, and we parametrize them at time t by a function σ t ∈ L 2 (I, R); we require that σ t satisfies the differential equation in L 2 (I, R)Our standing hypotheses on the potentials V and W are; moreover W , seen as a function on R, is even; up to adding a constant, we can suppose that W (0) = 0.There is an element of arbitrariness in choosing the lift of the particles to R and in parametrizing them; that's why we are less interested in the evolution of the labelling σ t than in the evolution of the measure it induces. In other words, we want to study the measures on S 1 × R given by μ t := (π • σ t ,σ t ) ν 0 , where ν 0 denotes the Lebesgue measure on I, π : R → S 1 is the natural projection and (·) denotes the push-forward. A standard calculation shows that, if σ t satisfies (ODE) Lag , then μ t satisfies, in the weak sense,