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SUMMARY:Observable Gravitational Wave Strain at Second-order
DTSTART;VALUE=DATE-TIME:20260521T083000Z
DTEND;VALUE=DATE-TIME:20260521T084500Z
DTSTAMP;VALUE=DATE-TIME:20260530T171909Z
UID:indico-contribution-2459@indico.itp.ac.cn
DESCRIPTION:Speakers: Ao Wang (Institute for Theoretical Physics\, Chinese
  Academy of Science)\nThe definition of second-order gravitational wave (G
 W) strain in cosmological perturbation theory is traditionally ambiguous d
 ue to its dependence on spacetime slicing. This issue is particularly crit
 ical for secondary GWs induced by primordial fluctuations. This talk intro
 duces a gauge-invariant formalism that defines GW strain via the time-dela
 y of electromagnetic signals exchanged between geodesic observers. Our res
 ults confirm that this observable strain aligns with the transverse-tracel
 ess components in the Newton gauge\, providing a robust physical foundatio
 n for interpreting secondary GWs and resolving the gauge-dependence contro
 versy.\n\nhttps://indico.itp.ac.cn/event/419/contributions/2459/
LOCATION:Small Lecture Hall\, Chongqing University Library (图书馆小
 报告厅) 1F-9
URL:https://indico.itp.ac.cn/event/419/contributions/2459/
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