# Pujian Mao

## Publications Authored By Pujian Mao

Recently, the leading soft gluon theorem with single soft emission was shown to be the Ward identity of a two dimensional $\cal G$-Kac-Moody symmetry. In this note, we show that the leading soft gluon theorem can be interpreted as the Ward identity for the asymptotic symmetries of non-Abelian gauge theory. We further argue that the sub-leading soft gluon theorem can follow from the same symmetry. Read More

In this paper, we present a new type of electromagnetic memory. It is a `magnetic' type, or B mode, radiation memory effect. Rather than a residual velocity, we find a position displacement of a charged particle induced by the B mode radiation with memory. Read More

In a previous article, we have argued that Low's sub-leading soft photon theorem can be recovered as a Ward identity associated to the same large gauge transformations that control the leading piece of the theorem. The key for that was to link the frequency expansion displayed in the soft theorem to a 1/r expansion that we can perform in the associated asymptotic charge. We expect this idea to be valid in general, and here we provide compelling evidence for it by showing how the same method works in the case of Einstein-Hilbert gravity. Read More

We derive the expressions for the local, on-shell closed co-dimension 2 forms in the Cartan formulation of general relativity and explicitly show their equivalence to those of the metric formulation. Read More

Inspired by the recent proposal of soft hair on black holes in Phys. Rev. Lett. Read More

It has long been known that the soft factor appearing in the soft photon theorem contains a leading and a sub-leading piece (in the inverse frequency of the photon). It has been recently shown that the leading soft factor can be understood as the Ward identity of a symmetry at null infinity, namely certain residual (large) gauge transformations of the gauge theory. In this note we argue that the sub-leading soft factor follows from the same symmetry. Read More

Three-dimensional Einstein-Maxwell theory with non trivial asymptotics at null infinity is solved. The symmetry algebra is a Virasoro-Kac-Moody type algebra that extends the bms3 algebra of the purely gravitational case. Solution space involves logarithms and provides a tractable example of a polyhomogeneous solution space. Read More