Radiative observables for linearized gravity on asymptotically flat spacetimes and their boundary induced states

Abstract

We discuss the quantization of linearized gravity on globally hyperbolic, asymptotically flat, vacuum spacetimes and the construction of distinguished states which are both of Hadamard form and invariant under the action of all bulk isometries. The procedure, we follow, consists of looking for a realization of the observables of the theory as a sub-algebra of an auxiliary, non-dynamical algebra constructed on future null infinity ℑ + . The applicability of this scheme is tantamount to proving that a solution of the equations of motion for linearized gravity can be extended smoothly to ℑ + . This has been claimed to be possible provided that a suitable gauge fixing condition, first written by Geroch and Xanthopoulos, is imposed. We review its definition critically showing that there exists a previously unnoticed obstruction in its implementation leading us to introducing the concept of radiative observables. These constitute an algebra for which a Hadamard state induced from null infinity and invariant under the action of all spacetime isometries exists and it is explicitly constructed.

Towards quantum field theory on spacetimes with boundaries

“…linearized gravity -see in Ref. [6], and by F-locality. When Ω = H 4 , we can give explicit examples of states.…”

Hadamard States from Light-like Hypersurfaces

“…To conclude this section we stress that, although in this book, we will only focus on real scalar fields, the methods devised can be used also to discuss other scenarios, such as Dirac fields [DHP11] free electromagnetism [DS13,Si11] or linearised gravity [BDM14].…”

Linear Yang–Mills Theory as a Homotopy AQFT

“…[SDH14, BDS14, BDHS14, FL16, Ben16, BSS16], but there also exist similar developments for e.g. linearized gravity [FH13,BDM14,Kha16,Kha18] and linearized supergravity [HS13]. In addition to such non-interacting models, examples of perturbatively interacting quantum gauge theories were constructed in [Hol08, FR12, FR13, TZ18] by means of an appropriate adaption of the BRST/BV formalism to AQFT.…”