Research Talk 5 - Crossing beyond scattering amplitudes

          @misc{ pirsa_PIRSA:23070018,
            doi = {10.48660/23070018},
            url = {https://pirsa.org/23070018},
            author = {},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {Research Talk 5 - Crossing beyond scattering amplitudes},
            publisher = {Perimeter Institute},
            year = {2023},
            month = {jul},
            note = {PIRSA:23070018 see, \url{https://pirsa.org}}
          }
          

Abstract

What can be measured asymptotically in quantum field theory? Among the answers to this question are scattering amplitudes, but also a whole compendium of inclusive measurements, such as expectation values of gravitational radiation and out-of-time-ordered amplitudes. We show that these asymptotic observables can be related to one another through new versions of crossing symmetry. Assuming analyticity, we propose generalized crossing relations and corresponding paths of analytic continuation. Throughout the talk, we show how to apply crossing in practice, using various tree- and loop-level examples.