Celestial Holography and Gravitational-Wave Memory in Quadratic Gravity

Paper One We comment on the ultraviolet completion of the Big Bang proposed by Liu, Quintin & Afshordi (2026), in which quantum quadratic gravity provides a renormalizable, asymptotically free theory that dynamically generates inflation without an extra inflaton field. We highlight a natural connection to celestial holography. Gravitational-wave memory effects — permanent spacetime scars carrying displacement, spin, and helicity information — map naturally onto operators in the two-dimensional celestial conformal field theory on the celestial sphere via the Pasterski–Strominger–Zhiboedov (PSZ) triangle. Recent results in quadratic gravity suggest these infrared observables remain well-defined within a UV-complete framework extending to the asymptotic null boundary. First paper in a three-part theoretical programme: Holographic Memory and Cyclic Cosmology.