Holography in asymptotically flat space-times and the BMS group

TL;DR

This paper explores the holographic principle in asymptotically flat space-times, focusing on the BMS group, and constructs a BMS phase space and Hamiltonian to understand boundary data at null infinity.

Contribution

It extends previous work by analyzing the BMS group's role in holography, connecting IR sectors with BMS representations, and constructing a phase space and Hamiltonian for boundary fields.

Findings

Mapped bulk and boundary symmetries highlighting differences from AdS/CFT.

Connected IR sectors of gravity with BMS group representations.

Constructed a BMS phase space and free Hamiltonian for boundary fields.

Abstract

In a previous paper (hep-th/0306142) we have started to explore the holographic principle in the case of asymptotically flat space-times and analyzed in particular different aspects of the Bondi-Metzner-Sachs (BMS) group, namely the asymptotic symmetry group of any asymptotically flat space-time. We continue this investigation in this paper. Having in mind a S-matrix approach with future and past null infinity playing the role of holographic screens on which the BMS group acts, we connect the IR sectors of the gravitational field with the representation theory of the BMS group. We analyze the (complicated) mapping between bulk and boundary symmetries pointing out differences with respect to the AdS/CFT set up. Finally we construct a BMS phase space and a free hamiltonian for fields transforming w.r.t BMS representations. The last step is supposed to be an explorative investigation of the boundary data living on the degenerate null manifold at infinity.