Würzburg 2018 – scientific programme

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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik

MP 5: Quantum Field Theory I

MP 5.2: Talk

Wednesday, March 21, 2018, 11:45–12:05, Z6 - SR 1.012

Closing cumulant hierarchies: Quantal methods for classical dynamics — •Cora Uhlemann — DAMTP, University of Cambridge

Nonlinear problems in manifold areas of physics (such as cosmology, plasma physics and hydrodynamics including turbulence) are described by an infinite hierarchy of coupled differential equations for cumulants. Typically, truncations are based on fluid-like approximations that cannot capture the phenomenology of the system featuring multiple streams. I suggest to take a closer look at closure schemes that rely on the correspondence principle connecting quantal and classical dynamics. I will illustrate this idea for the gravitational clustering of dark matter, described by a phase-space distribution solving the Vlasov-Poisson equation. I will show that an approximate phase-space distribution can be constructed from a wave function solving the Schrödinger-Poisson equation. Hence, 6-dimensional phase-space information can be encoded in two functions on 3-dimensional position space that consistently generate cumulants at all orders. This provides a starting point for constructing approximate closure schemes that are consistent with the nonlinear dynamics.