Quantum State of the Asymptotic Gravity Field from BRST Quantization
Calmet X.

Received: June 18, 2026

DOI: 10.31857/S0044451026110033

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The quantum state of the asymptotic linearized gravity field of a compact energy source is derived using BRST quantization. Barnich has previously derived the quantum state of the U(1) field in QED using the Gauss law constraint. The role of Gauss's law is now played by the linearized Hamiltonian and momentum constraints in gravity. For a static mass source, only the scalar Hamiltonian constraint is shifted. The quantum state corresponding to the static Newton field originates in the non-radiative scalar constraint sector, not in the propagating transverse-traceless graviton sector. Implications for holography and for black hole information are discussed: 1) the exact quantum state of the compact source is encoded in the asymptotic quantum state of its gravity field; 2) Hawking amplitudes are dependent, via the gravity state outside the horizon, on the black hole internal state. Keywords: BRST quantization, linearized gravity, coherent states, gravitational constraints, quantum hair, black holes Contribution for the JETP special issue dedicated to black hole physics (Hawking black hole evaporation)