Black Holes and Time: Opinion

Time dependent black holes and thermal equilibration

We study aspects of a recently proposed exact time dependent black hole solution of IIB string theory using the AdS/CFT correspondence. The dual field theory is a thermal system in which initially a vacuum density for a non-conserved operator is turned on. We can see that in agreement with general thermal field theory expectation the system equilibrates: the expectation value of the non-conserv...

Long Time Scales and Eternal Black Holes

We discuss the various scales determining the temporal behaviour of correlation functions in the presence of eternal black holes. We point out the origins of the failure of the semiclassical gravity approximation to respect a unitarity-based bound suggested by Maldacena. We find that the presence of a subleading (in the large-N approximation involved) master field does restore the compliance wi...

Massive Black Holes across Cosmic Time Massive Black Holes across Cosmic Time

Dirty Black Holes and Hairy Black Holes.

An approach based on considerations of the non-classical energy momentum tensor outside the event horizon of a black hole provides additional physical insight into the nature of discrete quantum hair on black holes and its effect on black hole temperature. Our analysis both extends previous work based on the Euclidean action techniques, and corrects an omission in that work. We also raise sever...

Time–dependent Hypercritical Accretion onto Black Holes

Stationary spherical accretion onto black holes is certainly a well–known and extensively studied topic (for a comprehensive review see Nobili, Turolla and Zampieri , Zampieri, Miller and Turolla ). Up to now all time–dependent investigations of spherical accretion have been concerned either with the analysis of the stability of isothermal , isentropic 4 and optically thick 6 flows or with the ...