BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:HEP Colloquia 2025
DTSTART:20251209T153000Z
DTEND:20251209T163000Z
DTSTAMP:20260506T021800Z
UID:indico-event-49639@agenda.infn.it
CONTACT:hepcolloquia@ca.infn.it
DESCRIPTION:Speakers: Zakaria Belkhadria (Université de Genève/ Universi
 tà di Cagliari / Istituto Nazionale di Fisica Nucleare / GWSC)\n\nNew Asp
 ects of spontaneous scalarization of black holes beyond General relativity
  \nSpontaneous scalarization is a mechanism that allows black holes to de
 velop a non-trivial profile of a scalar field “scalar hair” because of
  tachyonic instabilities\, enabling tests of gravity beyond General Relati
 vity. Motivated by stability and threshold issues in Gauss-Bonnet scalariz
 ation\, we propose a new model characterized by two nonminimal couplings o
 f the scalar field to both Gauss-Bonnet curvature and a U(1) gauge field (
 e.g. electromagnetic field). The presence of two distinct sources of tachy
 onic instability broadens the conditions for spontaneous scalarization. We
  track how the electric charge and the coupling constants govern the onset
  of the scalar field and derive new solution branches with nontrivial scal
 ar profiles. Numerical integration shows multiple coexisting scalarized bl
 ack hole solutions with adjustable thresholds\, influenced by the relative
  strengths of curvature and matter couplings. We examine their scalar char
 ge\, horizon properties\, and thermodynamic characteristics\, demonstratin
 g how the model can selectively activate or suppress scalarization phenome
 na. The matter source term modifies the scalarization onset and promotes s
 table solutions\, as indicated by the evolution of the scalar charge and h
 orizon quantities. These findings suggest an alternative approach to scala
 rization\, may avoid the instabilities of curvature-only or matter-only mo
 dels\, and offer new ways to test strong-gravity effects in upcoming obser
 vations.\n \n\nhttps://agenda.infn.it/event/49639/
LOCATION:Sala Consiliare (Department of Physics)
URL:https://agenda.infn.it/event/49639/
END:VEVENT
END:VCALENDAR