BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Superhorizon curvature perturbations in hybrid inflation
DTSTART;VALUE=DATE-TIME:20260521T084500Z
DTEND;VALUE=DATE-TIME:20260521T090000Z
DTSTAMP;VALUE=DATE-TIME:20260530T155548Z
UID:indico-contribution-2464@indico.itp.ac.cn
DESCRIPTION:Speakers: Anxianyi Xiong (ITP-CAS)\nWe utilize the $\\delta N$
  formalism within a parameter space formed by the $e$-folding number $N$ a
 nd its transverse subspace to explicitly account for the geometry of the f
 inal hypersurface in multi-field inflation. Applying this framework to hyb
 rid inflation\, we identify an enhancement mechanism of the curvature pert
 urbation driven by the growing isocurvature perturbation due to the tachyo
 nic instability of the waterfall field. This amplification occurs during t
 he trajectory's turn in field space\, a process qualitatively distinct fro
 m the background deceleration in single-field non-attractor models such as
  ultra-slow-roll. The resulting power spectrum features a broad peak with 
 a characteristic $k^3$ infrared growth and a ultraviolet spectral tilt tha
 t uniquely determines the nonlinear parameter $f_\\mathrm{NL}$ of a logari
 thmic non-Gaussianity\, all of which are primarily governed by the waterfa
 ll dynamics. The enhanced curvature perturbation can simultaneously accoun
 t for primordial black hole dark matter and a stochastic gravitational wav
 e background detectable by LISA\, Taiji\, and TianQin.\n\nhttps://indico.i
 tp.ac.cn/event/419/contributions/2464/
LOCATION:Small Lecture Hall\, Chongqing University Library (图书馆小
 报告厅) 1F-9
URL:https://indico.itp.ac.cn/event/419/contributions/2464/
END:VEVENT
END:VCALENDAR