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SUMMARY:Preheating on curved field-space manifolds
DTSTART;VALUE=DATE-TIME:20191016T093000Z
DTEND;VALUE=DATE-TIME:20191016T113000Z
DTSTAMP;VALUE=DATE-TIME:20191023T214520Z
UID:indico-event-837793@indico.cern.ch
DESCRIPTION:I will discuss preheating in multi-field models of inflation w
ith a curved field-space manifold. In the case of two-field generalizatio
ns of $\\alpha$-attractor models with is a highly curved hyperbolic field-
space manifold\, analytical progress can be made for preheating using the
WKB approximation and Floquet analysis. I will show the emergence of a sim
ple scaling behavior of the Floquet exponents for large values of the fiel
d-space curvature\, that enables a quick estimation of the reheating effi
ciency for any large value of the field-space curvature. In this regime on
e can observe and explain universal preheating features that arise for dif
ferent values of the potential steepness. In general preheating is faster
for larger negative values of the field-space curvature and steeper potent
ials. For very highly curved field-space manifolds preheating is essential
ly instantaneous.\n\nIn case of multi-field models with non-minimal coupli
ngs\, where the field-space in the Einstein frame is highly curved near th
e origin\, I will describe recent lattice simulations that have been used
to capture significant nonlinear effects like backreaction and rescatterin
g. I will show how we can we extract the effective equation of state and t
ypical time-scales for the onset of thermalization\, quantities that could
affect the usual mapping between predictions for primordial perturbation
spectra and measurements of anisotropies in the cosmic microwave backgroun
d radiation. For large values of the nonminimal coupling constants\, eff
icient particle production gives rise to nearly instantaneous preheating.
Moreover\, the strong single-field attractor behavior that was identified
for these models in linearized analyses remains robust in the full theory\
, and in all cases considered the attractor persists until the end of preh
eating. Finally\, I will discuss the implications for Higgs inflation.\n\n
https://indico.cern.ch/event/837793/
LOCATION:CERN 4/2-011 - TH common room
URL:https://indico.cern.ch/event/837793/
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