BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-8156
DTSTART:20230412T180000Z
DTEND:20230412T193000Z
DTSTAMP:20260414T050619Z
LAST-MODIFIED:20230410T213138Z
LOCATION:Chamberlin 5280
SUMMARY:Late-time accelerating cosmologies\, Theory Seminar (High Ener
 gy/Cosmology)\, Flavio Tonioni\, UW Madison
DESCRIPTION:In this talk\, I will characterize the late-time expansion
  rate of the universe in scalar-field cosmologies with multi-exponenti
 al potentials. To do this\, I will take advantage of previously unobse
 rved universal asymptotic features of the solutions to the cosmologica
 l equations. This is a critical achievement because it provides a simp
 le diagnostic of whether any given multi-exponential potential holds t
 he necessary conditions for late-time cosmic acceleration. Such potent
 ials have been studied extensively as phenomenological models of quint
 essence and\, moreover\, they are ubiquitous in string-theoretic const
 ructions\, which further allows one to sharpen several statements on t
 he low-energy signatures of quantum gravity. I will extensively commen
 t on the tension for acceleration posed by the string-theoretic dilato
 n\, which\, if present as a rolling scalar in a weakly-coupled theory\
 , makes the potential too steep for acceleration unless negative-defin
 ite potentials are present. I will also show that\, if the late-time s
 cale factor is of power-law form\, the acceleration parameter can be e
 xpressed in terms of a directional derivative of the potential.
URL:https://www.physics.wisc.edu/events/?id=8156
END:VEVENT
END:VCALENDAR