Title：Nonlinear detection of Hermitian connections in Minkowski space 

Speaker：Xi Chen （剑桥大学） 

Time：2018年12月12日（周三）    下午  16:00-17:30

Room：东区第五教学楼 5106

Abstract： I will describe how to recover a Hermitian connection from the source-to-solution map of a cubic non-linear wave equation in Minkowski space; the equation is naturally motivated by the Yang-Mills-Higgs equations. Through a linearization trick, we convert the cubic non-linearity to the nonlinear interaction of three linear waves. The collision of the three waves creates new propagating singularities and makes a broken geodesic. By the microlocal analysis of intersecting Lagrangian distributions, we reduce the recovery to a geometric problem: recovering a connection from its broken non-abelian X-ray transform along light rays. This is joint work with M. Lassas (Helsinki), L. Oksanen (UCL), G. Paternain (Cambridge).