Lecture notes prepared for the 2021 SAGEX PhD School in Amplitudes hosted by the
University of Copenhagen August 10th through 13th. Topics covered include: the …

Conformal field theories have been long known to describe the fascinating universal physics
of scale invariant critical points. They describe continuous phase transitions in fluids …

We review the role that infinite-dimensional symmetries arising at the boundary of
asymptotically flat spacetimes play in the context of the celestial holography program. Once …

A bstract Conformal theory correlators are characterized by the spectrum and three-point
functions of local operators. We present a formula which extracts this data as an analytic …

A bstract We describe in more detail the general relation uncovered in our previous work
between boundary correlators in de Sitter (dS) and in Euclidean anti-de Sitter (EAdS) space …

A bstract We argue that every CFT contains light-ray operators labeled by a continuous spin
J. When J is a positive integer, light-ray operators become integrals of local operators over a …

The four-dimensional (4D) Lorentz group SL (2, C) acts as the two-dimensional (2D) global
conformal group on the celestial sphere at infinity where asymptotic 4D scattering states are …

We study solutions of the Klein-Gordon, Maxwell, and linearized Einstein equations in R 1,
d+ 1 that transform as d-dimensional conformal primaries under the Lorentz group SO (1, d+ …

A bstract It is a long-standing conjecture that any CFT with a large central charge and a large
gap∆ gap in the spectrum of higher-spin single-trace operators must be dual to a local …

A bstract Caron-Huot has recently given an interesting formula that determines OPE data in
a conformal field theory in terms of a weighted integral of the four-point function over a …