Piazza dei Cavalieri, 7

56126 Pisa-Italy tel: +39 050 509111

fax: +39 050 563513 19/01/2018

SEMINARIO DI FISICA TEORICA

Lunedì 22 gennaio 2018

ore 14:30

Scuola Normale Superiore

Pisa

Aula Bianchi

Lance Dixon (SLAC, Stanford)

Terrà un seminario dal titolo:

“Polylogarithmic Polygon Origami”

Abstract:

Scattering amplitudes in planar N=4 super-Yang-Mills theory are dual to light-like polygonal Wilson-loop

expectation values. In many cases their perturbative expansion can be expressed in terms of multiple

polylogarithms which also obey certain single-valuedness conditions or branch cut restrictions. The rigidity of this

function space, together with a few other conditions, allows one to construct the six-point amplitude -- or

hexagonal Wilson loop -- through 6 loops, and the (symbol of the) seven-point amplitude through 4 loops. Then

one can "fold" the polygonal Wilson loops into multiple degenerate configurations, expressing the limiting

behavior in terms of simpler function spaces, and learning in the process about how amplitudes factorize. The

polylogarithms, and the multiple zeta values to which they evaluate at specific points, satisfy a Hopf algebra

coproduct structure, and additional relations coming from "Cosmic Galois Theory".

Tutti gli interessati sono invitati a partecipare.

Classe di Scienze Matematiche e Naturali