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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-2849
DTSTART:20121113T220000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T021617Z
LAST-MODIFIED:20121112T155855Z
LOCATION:5280 Chamberlin
SUMMARY:Cosmological Perturbations: Isocurvature\, Vorticity and Magne
 tic Fields\, Theory Seminar (High Energy/Cosmology)\, Adam Christopher
 son\, University of Nottingham
DESCRIPTION:In this talk I will discuss some recent\, complementary wo
 rk that I have undertaken using cosmological perturbation theory\, a p
 owerful technique for modeling inhomogeneities in the universe. After 
 a brief review of the basics\, I introduce isocurvature\, or non-adiab
 atic pressure perturbations\, and calculate their spectrum in the sett
 ings of standard\, concordance cosmology\, and inflationary models inv
 olving two scalar fields. I then extend the discussion beyond linear p
 erturbations\, and show that vorticity can be sourced at second order 
 with only scalar perturbations\, the source term being quadratic in th
 e gradients of first order energy density and non-adiabatic pressure p
 erturbations. I present a first estimate of this vorticity's power spe
 ctrum\, and highlight some potential observational consequences. One o
 f these is the possible sourcing of sizeable magnetic fields\, and I b
 riefly sketch some current work on including magnetic fields in pertur
 bation theory in a consistent way. I close with some ideas for future 
 work.
URL:https://www.physics.wisc.edu/events/?id=2849
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