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CATEGORIES:Cosmology Lunch
SUMMARY:Ultra-slow-turn inflation - Ana Achúcarro (Leiden 
 U. &amp\; Basque U.\, Bilbao)
DTSTART;TZID=Europe/London:20260223T130000
DTEND;TZID=Europe/London:20260223T140000
UID:TALK242626AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/242626
DESCRIPTION:Multifield inflation models involving ultra-light 
 fields such as moduli and axions  are a generic ou
 tcome of string and supergravity cosmology. In thi
 s talk we consider under what conditions their pri
 mordial perturbation spectra may be consistent wit
 h observations on the largest (CMB) scales.  The u
 sual route is to stabilise the light fields so as 
 to recover single-field inflation. Another possibi
 lity is if massless\, frozen isocurvature perturba
 tions can source adiabatic perturbations efficient
 ly over many e-folds. I will discuss a third optio
 n\, that has emerged more recently\, in which the 
 isocurvature perturbations are tachyonic (unstable
 ) but the instability is shut off by an exponentia
 lly decaying turning rate. We call this regime “ul
 tra-slow-turn” (by analogy with the ultra-slow-rol
 l regime where the first slow roll parameter decay
 s exponentially). \n[Based on an upcoming paper wi
 th P. Christodoulidis\, J-O. Gong and O. Iarygina.
 ]
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Roo
 m]
CONTACT:Gonzalo Villa
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