Black-Hole Evolution from Stellar Collapse

We present a local approach towards black-hole evaporation, which relies on the absence of quantum phase transition across the stellar surface. We show that this approach augmented with Bekenstein's black-hole entropy gives the Hawking effect if the null energy condition is violated in the initial quantum-field vacuum. If otherwise, an astrophysical black hole may then be expanding, that corresponds to the anti-Hawking effect, i.e. a positive-energy radiation flows into the black hole, taking its origin far away from the event horizon. This quantum process is reverse to the Hawking effect, as the latter is described by a negative-energy influx nearby the horizon, which goes over to a positive-energy outflux in the far-horizon region. We also provide examples of quantum vacua well-known in the literature, which give rise to both quantum effects from stellarcollapse. A local approach towards black-hole evaporation is presented, which relies on the absence of quantum phase transition across the stellar surface. It is shown that this approach augmented with Bekenstein's black-hole entropy gives the Hawking effect if the null energy condition is violated in the initial quantum-field vacuum. If otherwise, an astrophysical black hole may then be expanding, that corresponds to the anti-Hawking effect, i.e. a positive-energy radiation flows into the black hole, taking its origin far away from the event horizon. This quantum process is reverse to the Hawking effect, as the latter is described by a negative-energy influx nearby the horizon, which goes over to a positive-energy outflux in the far-horizon region. The author also provides examples of quantum vacua well-known in the literature, which give rise to both quantum effects from stellar collapse.