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arXiv · 1106.5628

Unitarity alternatives in the reduced-action model for gravitational collapse

M. Ciafaloni·D. Colferai·G. Falcioni
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Abstract

Based on the ACV approach to transplanckian energies, the reduced-action model for the gravitational S-matrix predicts a critical impact parameter b_c ~ R = 2 G sqrt{s} such that S-matrix unitarity is satisfied in the perturbative region b > b_c, while it is exponentially suppressed with respect to s in the region b < b_c that we think corresponds to gravitational collapse. Here we definitely confirm this statement by a detailed analysis of both the critical region b ~ b_c and of further possible contributions due to quantum transitions for b < b_c. We point out, however, that the subcritical unitarity suppression is basically due to the boundary condition which insures that the solutions of the model be ultraviolet-safe. As an alternative, relaxing such condition leads to solutions which carry short-distance singularities presumably regularized by the string. We suggest that through such solutions - depending on the detailed dynamics at the string scale - the lost probability may be recovered.

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M. Ciafaloni, D. Colferai, G. Falcioni. 2011-06-28. Unitarity alternatives in the reduced-action model for gravitational collapse. https://doi.org/10.1142/9789814374552_0164

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