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SUMMARY:From locality and unitarity to cosmological correlators - David St
 efanyszyn (DAMTP)
DTSTART:20210521T120000Z
DTEND:20210521T130000Z
UID:TALK158686@talks.cam.ac.uk
CONTACT:Justin Ripley
DESCRIPTION:The on-shell approach to computing scattering amplitudes has p
 roduced tremendous progress in particle physics. The combination of symmet
 ries\, locality and unitarity allows one to efficiently explore the space 
 of consistent effective theories of massless particles without using Lagra
 ngians or introducing gauge redundancies. Effort has recently turned to ap
 plying a similar logic to “bootstrap" the fundamental observables in cos
 mology\, namely cosmological correlators that live on the late-time bounda
 ry of an approximately de-Sitter spacetime. After outlining the success of
  the on-shell approach for particle physics\, I will explain how we can ef
 ficiently bootstrap three and four point functions in the effective field 
 theory of inflation by using a small number of physical principles. I will
  also show how this new approach to computing cosmological observables all
 ows us to make some very general statements about parity-violating gravita
 tional interactions on inflationary backgrounds. 
LOCATION:Zoom
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