Thermal duality and gravitational collapse

Thermal duality is a relationship between the behaviour of het-erotic string models of the E(8)xE(8) or SO(32) types at inversely related temperatures, a variant of T duality in the Euclidean regime. This duality would have consequences for the nature of the Hagedorn transition in these string models. We propose that the vacuum admits a family of deformations in situations where there are closed surfaces of constant area but high radial acceleration (a string regularized ver-sion of a Penrose trapped surface), such as would be formed in situ-ations of extreme gravitational collapse. This would allow a radical resolution of the firewall paradox by allowing quantum effects to sig-nificantly modify the spacetime geometry around a collapsed object. A string bremsstrahlung process would convert the kinetic energy of infalling matter in extreme gravitational collapse to form a region of the deformed vacuum, which would be equivalent to forming a high temperature string phase. A heuristic criterion for the conversion pro-cess is presented, relating Newtonian gravity to the string tension, suggesting an upper limit to the strength of the gravitational interac-tion. This conversion process might have observable consequences for charged particles falling into a rotating collapsed object by producing high energy particles via a variant of the Penrose process.