Coherent energy cascades in (semi-)random Hamiltonian systems.
Coherent energy cascades in (semi-)random Hamiltonian systems.
The problem of Sobolev norm growth鈥攏amely, the search for mechanisms of energy transfer from low to arbitrarily high modes鈥攈as 听been intensively studied in Hamiltonian systems with an organized, 听deterministic structure of mode interactions, such as the cubic 听nonlinear Schr枚dinger equation. In this talk, I will present an 听extension of this problem to Hamiltonian systems dominated by random nonlinear interactions. I will introduce analytic solutions describing three types of energy cascades that lead either to unbounded growth or to finite-time blow-up of Sobolev norms.I will then present numerical simulations demonstrating the emergence 听of these dynamics from incoherent initial conditions. Taken together, these results demonstrate that coherent (phase-organized) energy 听cascades can be robust mechanisms of energy transfer even in systems with a random structure.