4 papers
Universal Polarimetric Signatures of the Black Hole Photon Ring
Elizabeth Himwich, Michael D. Johnson, Alexandru Lupsasca +1
Black hole images present an annular region of enhanced brightness. In the absence of propagation effects, this "photon ring" has universal features that are completely governed by…
Uplifting AdS3/CFT2 to Flat Space Holography
Adam Ball, Elizabeth Himwich, Sruthi A. Narayanan +2
Four-dimensional (4D) flat Minkowski space admits a foliation by hyperbolic slices. Euclidean AdS3 slices fill the past and future lightcones of the origin, while dS3 slices fill t…
A Note on the Subleading Soft Graviton
Elizabeth Himwich, Zahra Mirzaiyan, Sabrina Pasterski
We show that the soft part of the charge generating infinitesimal superrotations can be expressed, in harmonic gauge, in terms of metric components evaluated at the boundaries of n…
Celestial Current Algebra from Low's Subleading Soft Theorem
Elizabeth Himwich, Andrew Strominger
The leading soft photon theorem implies that four-dimensional scattering amplitudes are controlled by a two-dimensional (2D) Kac-Moody symmetry that acts on the celestial sp…