Nordita HEP Local Seminars

A semiclassical path to the cosmic web

by Dr Cora Uhlemann (Newcastle University)

Europe/Stockholm
132:028 (Nordita East)

132:028

Nordita East

Description

We chart a path towards solving for the nonlinear gravitational dynamics of dark matter using semiclassical methods. On large scales, dark matter can be treated as a perfect fluid. On small scales, gravitationally bound structures form through a cascade of multiple fluid streams. Capturing the development of this intricate structure in 6-dimensional phase space is challenging. We suggest to approximate the time evolution of the phase-space distribution using the quantum-classical correspondence. In this framework, one can solve a Schroedinger-type equation, where the small parameter hbar acts as a phase-space resolution scale. The leading-order solution is the semiclassical equivalent of the Zeldovich approximation, where particles move along straight trajectories. At next-to-leading order, we solve the semiclassical equation perturbatively and obtain the associated displacement and velocity fields. We illustrate in numerical examples that our solutions resemble Lagrangian Perturbation Theory, but protect key symmetries of the system. This provides interesting prospects for modelling the cosmic large-scale structure in the nonlinear regime.