82 citations · 274 across the 16 of their papers we have counts for
17 papers
Observing Massive Scattering from Null Infinity
Walker Melton, Kyrill Michaelsen, Romain Ruzziconi
Because massive particles asymptote to timelike rather than null infinity, current flat space holographic proposals such as celestial or Carrollian holography struggle to describe…
Flat Space Physics from AdS Actions
Walker Melton
Flat spacetimes are foliated by hyperbolic slices that are geometrically three-dimensional de Sitter or anti-de Sitter spaces. As such, it is possible to construct flat space holog…
Conformal Field Theory with Periodic Time
Walker Melton, Andrew Strominger
It is shown that time-ordered correlation functions of a unitary CFT in 2D Minkowski space admit a single-valued, conformally-invariant extension to the Lorentzian signature to…
Quantum Fields on Time-Periodic AdS
Walker Melton, Andrew Strominger, Tianli Wang
We consider a free complex massive scalar on the quotient spacetime AdS, which has the isometry group SO(2,2) rather than its universal cover. This problem is of int…
No-Boundary State for Klein Space
Walker Melton, Atul Sharma, Andrew Strominger +1
Analytic continuation from signature Minkowski to signature Klein space has emerged as a useful tool for the understanding of scattering amplitudes and flat space h…
A Celestial Dual for MHV Amplitudes
Walker Melton, Atul Sharma, Andrew Strominger +1
It is shown that a 2D CFT consisting of a central charge Liouville theory, a chiral level one, rank Kac-Moody algebra and a weight free fermion holographically gener…
Soft Algebras for Leaf Amplitudes
Walker Melton, Atul Sharma, Andrew Strominger
Celestial MHV amplitudes are comprised of non-distributional leaf amplitudes associated to an AdS leaf of a foliation of flat spacetime. It is shown here that the leaf amplitud…
Celestial Leaf Amplitudes
Walker Melton, Atul Sharma, Andrew Strominger
Celestial amplitudes may be decomposed as weighted integrals of AdS-Witten diagrams associated to each leaf of a hyperbolic foliation of spacetime. We show, for the Kleinian th…
Celestial Gluon Amplitudes from the Outside In
Walker Melton, Sruthi A. Narayanan
We show that, given a two-dimensional realization of the celestial OPE in self-dual Yang-Mills, we can find a scalar source around which scattering amplitudes replicate correlation…
Conformal Correlators on the Lorentzian Torus
Walker Melton, Atul Sharma, Andrew Strominger
The general form of a 2D conformal field theory (CFT) correlator on a Euclidean Riemann surface, Lorentzian plane or Lorentzian cylinder is well-known. This paper describes the gen…
Hyperbolic Vacua in Minkowski Space
Walker Melton, Filip Niewinski, Andrew Strominger +1
Families of Lorentz, but not Poincare, invariant vacua are constructed for a massless scalar field in 4D Minkowski space. These are generalizations of the Rindler vacuum with a lar…
Deforming Soft Algebras for Gauge Theory
Walker Melton, Sruthi A. Narayanan, Andrew Strominger
Symmetry algebras deriving from towers of soft theorems can be deformed by a short list of higher-dimension Wilsonian corrections to the effective action. We study the simplest of…
Celestial Amplitudes as AdS-Witten Diagrams
Eduardo Casali, Walker Melton, Andrew Strominger
Both celestial and momentum space amplitudes in four dimensions are beset by divergences resulting from spacetime translation and sometimes scale invariance. In this paper we consi…
Celestial Feynman Rules for Scalars
Walker Melton
Off-shell celestial amplitudes with both time-like and space-like external legs are defined. The Feynman rules for scalar amplitudes, viewed as a set of recursion relations for off…
Conformal Block Expansion in Celestial CFT
Alexander Atanasov, Walker Melton, Ana-Maria Raclariu +1
The 4D 4-point scattering amplitude of massless scalars via a massive exchange is expressed in a basis of conformal primary particle wavefunctions. This celestial amplitude is expa…
Eigenstates of Quasi-Keplerian Self-Gravitating Particle Discs
Walker Melton, Konstantin Batygin
Although quasi-Keplerian discs are among the most common astrophysical structures, computation of secular angular momentum transport within them routinely presents a considerable p…
Scattering and the Celestial Torus
Alexander Atanasov, Adam Ball, Walker Melton +2
Analytic continuation from Minkowski space to split signature spacetime has proven to be a powerful tool for the study of scattering amplitudes. Here we show that, under th…