BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Yuchen Du\, University of Virginia - Physics\n\n
Through string the ory\, people found interesting relations in particle theory. \;For exa mple\, \;Kawai-Lewellen-Tye (KLT) relation relates the scattering ampl itudes of QCD and gravity. However\, these kinds of relation are co mpletely mysterious from the point view of \;Quantum Field Theory sinc e the gravity Lagrangian \;seems totally unrelated to the Yang-Mills L agrangian. On the other \;hand\, these kinds of relations are neverthe less true and can be checked by computing the amplitudes using Feynman dia grams order by order. Thus the Feynman diagrammatic expansion does not cap ture everything of \;interest\, there are \;still hidden relations between different field theories. Worldline approach\, born as a first qu antized approach to calculate amplitudes\, shares a lot of similarities to string theory. \; \;In this talk\, I will show how worldline appr oach works and how \;it helps shed some light on the problems we are i nterested in. I will also discuss the subtlety and limitation of the appro ach and the possibility of generalizing it to "\;worldgraph approach&q uot\;.
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