BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Luminal scalar-tensor theories via couplings to photons
DTSTART;VALUE=DATE-TIME:20261107T093000Z
DTEND;VALUE=DATE-TIME:20261107T100000Z
DTSTAMP;VALUE=DATE-TIME:20261023T141935Z
UID:indico-contribution-2923@indico.itp.ac.cn
DESCRIPTION:Speakers: Arina Shtennikova (INR RAS & ITMP MSU)\nThe detectio
 n of GW170817 and its electromagnetic counterpart placed a stringent bound
  on the difference between the speeds of gravitational waves and light\, s
 everely restricting viable scalar-tensor models of dark energy. In particu
 lar\, large parts of Horndeski and beyond Horndeski theories appeared to b
 e ruled out as a description of late-time cosmic acceleration. In this tal
 k we revisit this conclusion. We argue that the constraint concerns the re
 lative propagation of gravitons and photons\, so a consistent treatment mu
 st include possible interactions between the dark energy scalar and the el
 ectromagnetic sector. Using Kaluza–Klein reductions of higher-dimensiona
 l scalar-tensor theories as a guiding principle\, we construct classes of 
 self-consistent scalar–vector–tensor theories within the DHOST framewo
 rk in which gravitational waves and light propagate with equal speeds on c
 osmological backgrounds. We discuss which of these couplings cannot be rem
 oved by conformal or disformal field redefinitions\, the fate of gravitati
 onal wave decay into dark energy\, and the implications for screening mech
 anisms and observational tests.\n\nhttps://indico.itp.ac.cn/event/417/cont
 ributions/2923/
LOCATION:
URL:https://indico.itp.ac.cn/event/417/contributions/2923/
END:VEVENT
END:VCALENDAR