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SUMMARY:Gravitational Phase-Space Turbulence: the Small-Scale Limit of the
  Cold-Dark-Matter Power-Spectrum - Barry Ginat / University of Oxford
DTSTART:20250514T124000Z
DTEND:20250514T130500Z
UID:TALK231985@talks.cam.ac.uk
CONTACT:128254
DESCRIPTION:The matter power spectrum is one of the fundamental quantities
  in the study of large-scale structure in cosmology. In this talk\, I will
  describe its small-scale asymptotic limit\, and give a theoretical argume
 nt to the effect that\, for cold dark matter\, P(k) has a universal asympt
 otic scaling with the wave-number k\, for k >> k_nl\, viz. P(k) ~ k^(-3). 
 I will explain how gravitational collapse drives a turbulent phase-space f
 low of the quadratic Casimir invariant\, where the linear and non-linear t
 ime scales are balanced\, and how this balance dictates the k dependence o
 f the power spectrum. The coldness of the dark-matter distribution functio
 n — its non-vanishing only on a 3-dimensional sub-manifold of phase-spac
 e — underpins the analysis. I will show Vlasov-Poisson simulations that 
 support the theory\, and if time permits\, also describe a stationary-phas
 e technique for deriving an equivalent result. 
LOCATION:The Hoyle Lecture Theatre + Zoom 
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