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SUMMARY:Seminar - Dr.Jishnu Sai P (Ewha Womans University)
DTSTART:20260826T020000Z
DTEND:20260826T030000Z
DTSTAMP:20260816T221200Z
UID:indico-event-11@ihepco.yonsei.ac.kr
DESCRIPTION:Title :  Inflationary trispectrum of gauge fields from scalar
  and tensor exchanges\nAbstract:\n\nIn this paper\, we compute the inflati
 onary trispectrum of primordial gauge fields generated through the scalar 
 and tensor exchanges in models with spectator U(1) gauge fields which are 
 kinetically coupled to the inflaton. Focusing on the connected four-point 
 autocorrelation function of gauge fields\, we derive exact analytical expr
 essions for the full trispectrum of both electric and magnetic fields usin
 g the in-in formalism and cosmological diagrammatic rules\, and explore th
 eir respective contributions in specific momentum configurations. For the 
 scalar exchange\, we find that the trispectrum signal in the equisided con
 figuration grows with the exchange momentum and reaches its maximum in the
  flattened limit. However\, in the counter collinear limit\, we show that 
 the non-linearity parameter associated with the trispectrum scales quadrat
 ically with the corresponding parameter of the cross-correlation bispectru
 m of magnetic fields and curvature perturbations\, thereby establishing a 
 hierarchical relation between the higher- and lower-order correlation func
 tions. For the tensor exchange\, the trispectrum displays a richer angular
  dependence\, reflecting the sensitivity to the orientation of the momentu
 m quadrilateral with respect to the tensor polarisation\, producing charac
 teristic angular modulations in the trispectrum. Detecting such angular si
 gnatures in future high-precision cosmological observations would provide 
 a novel window into tensor-mediated interactions in the early universe.\n\
 n \nPaper : https://arxiv.org/abs/2509.11143\n\nhttps://ihepco.yonsei.ac.
 kr/event/11/
URL:https://ihepco.yonsei.ac.kr/event/11/
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