BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Inflation from Fermion Condensation: Dynamics and Observational Si
 gnatures
DTSTART;VALUE=DATE-TIME:20261027T140000Z
DTEND;VALUE=DATE-TIME:20261027T143000Z
DTSTAMP;VALUE=DATE-TIME:20261020T114434Z
UID:indico-contribution-6124@cern.ch
DESCRIPTION:Speakers: Antonino Marciano (Fudan University)\nInflation is c
 onventionally described in terms of fundamental scalar fields whose micros
 copic origin remains unknown. We propose [1\,2] a fundamentally different 
 mechanism in which inflation emerges from fermion condensates generated by
  torsion-induced four-fermion interactions in Einstein–Cartan–Holst gr
 avity. Starting from a purely fermionic theory\, we derive a two-condensat
 e effective description whose inflationary dynamics resembles hybrid infla
 tion but exhibits a qualitatively new exit mechanism. \nThe central result
  is the emergence of a density-driven waterfall transition. During inflati
 on\, axial charge production continuously increases the fermion density an
 d the associated chiral chemical potential. Solving the finite-density gap
  equation\, we show that above a critical axial density the condensate no 
 longer admits a symmetry-broken solution. Inflation therefore terminates t
 hrough the evaporation of the condensate itself rather than through the in
 flaton crossing a critical field value. This mechanism naturally triggers 
 rapid energy transfer to fermionic degrees of freedom and provides a micro
 scopic realization of instant preheating. \nThe post-transition condensate
  is unstable to fragmentation into charged non-topological solitons. These
  objects can subsequently collapse into primordial black holes\, generatin
 g a calculable relic population whose properties are determined by the sam
 e condensate dynamics that drives inflation [3]. Because the underlying th
 eory is intrinsically chiral and connected to dynamical Chern–Simons gra
 vity\, the scenario simultaneously predicts parity-violating signatures [4
 ].\nThe framework unifies inflation\, reheating\, soliton formation\, prim
 ordial-black-hole production\, and parity-violating phenomenology within a
  single gravitationally induced fermion-condensation mechanism. It provide
 s a composite alternative to scalar-field inflation and identifies correla
 ted observational signatures that can test the role of spacetime torsion i
 n the early Universe.\n\nReferences\n[1] S. Alexander\, P. Chen\, J. Liu\,
  A. Marciano\, M. Sasaki and X. L. Su\, Hybrid inflation from fermion cond
 ensation\, Phys. Lett. B 873 (2026)\, 140193 doi:10.1016/j.physletb.2026.1
 40193 arXiv:2509.25290 [gr-qc]]\n[2] S. Alexander\, P. Chen\, J. Liu\, A. 
 Marciano\, M. Sasaki and X. L. Su\, Fermion Condensate Inflation\, Dynamic
 al Waterfall Mechanism and Primordial Black Holes\, arXiv:2604.21535 [hep-
 th].\n[[3] E. Cotner\, A. Kusenko\, M. Sasaki and V. Takhistov\, Analytic 
 Description of Primordial Black Hole Formation from Scalar Field Fragmenta
 tion\, JCAP 10 (2019)\, 077 doi:10.1088/1475-7516/2019/10/077 arXiv:1907.1
 0613 [astro-ph.CO].\n[4] J. Liu\, S. Alexander and A. Marciano\, Birefring
 ence in fermion-attenuated gravitational wave power spectrum\, Phys. Lett.
  B 866 (2025)\, 139499 doi:10.1016/j.physletb.2025.139499 arXiv:2501.08240
  [gr-qc].\n\nhttps://indico.particle.mephi.ru/event/626/contributions/6124
 /
LOCATION:Sevastopol hotel Conference Hall 2
URL:https://indico.particle.mephi.ru/event/626/contributions/6124/
END:VEVENT
END:VCALENDAR