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SUMMARY:An On-Shell Approach to Black-Hole Merger Waveforms
DTSTART:20260910T020000Z
DTEND:20260910T030000Z
DTSTAMP:20260910T220200Z
UID:indico-event-30764@indico.ihep.ac.cn
DESCRIPTION:Speakers: Andrea  Cristofoli (Kyoto University)\n\nScattering-
 amplitude methods are revolutionizing our understanding of black-hole dyna
 mics. To date\, however\, this program has focused primarily on black-hole
  scattering\, while the merger regime has largely been regarded as beyond 
 its reach. In this talk\, I will present a framework aimed at extending th
 e amplitude approach to this regime. I will first review how scattering wa
 veforms are extracted from on-shell amplitudes and then introduce a new fr
 amework for merger radiation\, in which a black-hole merger is formulated 
 as an inclusive on-shell transition from two incoming black holes to a rem
 nant accompanied by radiation. Following the logic of effective field theo
 ry\, the construction separates the soft radiative sector from the unresol
 ved hard dynamics of the merger\, whose effects are encoded in effective o
 n-shell transition data. No direct use is made of Einstein’s equations o
 r geodesic equations. Instead\, generalized unitarity\, BCFW recursion\, a
 nd soft theorems provide the central tools\, yielding an effective S-matri
 x description of black-hole mergers grounded in modern particle-physics me
 thods. As applications of this framework\, I will show how it recovers key
  features of merger dynamics and radiation—including linear memory and t
 he formation of the remnant angular momentum—while systematically accoun
 ting for recoil\, nonlinear memory\, and tail effects.\n\nBrief biography:
 \nAndrea Cristofoli is a theoretical physicist working at the intersection
  of scattering amplitudes\, black-hole dynamics\, and gravitational-wave p
 hysics. He completed his PhD at the Niels Bohr Institute in Copenhagen as 
 a Marie Curie Fellow. He then joined the University of Edinburgh as a Rese
 arch Associate before moving to the Yukawa Institute for Theoretical Physi
 cs at Kyoto University after being awarded a JSPS Fellowship. His research
  aims to reformulate classical gravity in the language of modern quantum f
 ield theory\, deriving black-hole dynamics and gravitational radiation dir
 ectly from scattering amplitudes.\n\nhttps://indico.ihep.ac.cn/event/30764
 /
LOCATION:S408
URL:https://indico.ihep.ac.cn/event/30764/
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