Space-time structure, asymptotic radiation and information recovery for a quantum hybrid state

Abstract: A hybrid quantum state is a combination of the Hartle-Hawking state for the physical particles and the Boulware state for the non-physical ones (such as ghosts), as was introduced in our earlier work [1]. We present a two-dimensional example, based on the RST model, when the corresponding back-reacted spacetime is a causal diamond, geodesically complete and free of the curvature singularities. In the static case it shows no presence of the horizon while it has a wormhole structure mimicking the black hole. In the dynamical case, perturbed by a pulse of classical matter, there appears an apparent horion while the spacetime remains to be a regular causal diamond. We compute the asymptotic radiation both in the static and dynamic case. We define entropy of the asymptotic radiation and demonstrate that as a function of the retarded time it shows the behavior typical for the Page curve. We suggest interpretation of our findings in terms of correlations in the virtual pairs of physical and non-physical particles spontaneously created in the spacetime.