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SUMMARY:Geodesic Focusing Conditions in  f(Q) Gravity
DTSTART;VALUE=DATE-TIME:20261025T060000Z
DTEND;VALUE=DATE-TIME:20261025T062000Z
DTSTAMP;VALUE=DATE-TIME:20261025T034357Z
UID:indico-contribution-3002@indico.itp.ac.cn
DESCRIPTION:Speakers: Chunhui Liu (HIAS\,UCAS)\nIn this talk\, I will disc
 uss the focusing of timelike geodesic congruences in $f(Q)$ gravity. I wil
 l first introduce geodesic deviation in symmetric teleparallel geometry an
 d the modified Raychaudhuri equation obtained under a Weyl-type nonmetrici
 ty ansatz and an additional nonmetricity–acceleration condition. I will 
 then present a focusing condition expressed in terms of the matter energy-
 momentum trace and an effective trace\, and discuss the compatibility of t
 he ansatz with homogeneous and isotropic connections. Finally\, I will con
 sider a shear-free flat FLRW background in the compatible coincident-gauge
  sector\, where the modified Friedmann equations yield $T_\\text{eff} = T$
  for $f_Q>0$. Under these assumptions\, the focusing inequality is saturat
 ed and imposes no additional constraint on the matter content.\n\nhttps://
 indico.itp.ac.cn/event/427/contributions/3002/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3002/
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