# Can string theory reproduce Hawking radiation in non-extremel black holes in 4D?

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can string theory reproduce hawking radiation in non-extremel black holes in 4D? i.e physically realistic black holes. do they exactly match hawking's calculations?

what is the interpretation of hawking radiation in string theory?

Demystifier

Demystifier
Gold Member
I think the best answer is - nobody knows so far.

I think the best answer is - nobody knows so far.

is there a string theory equivalent of this?

https://arxiv.org/abs/1612.05364
Semi-classical analysis of black holes in Loop Quantum Gravity: Modelling Hawking radiation with volume fluctuations
Pierre Heidmann, Hongguang Liu, Karim Noui
(Submitted on 16 Dec 2016)
We introduce the notion of fluid approximation of a quantum spherical black hole in the context of Loop Quantum Gravity. In this limit, the microstates of the black hole are intertwiners between "large" representations si" role="presentation">si
which typically scale as si&#x223C;aH" role="presentation">si∼√aH where aH" role="presentation">aH denotes the area of the horizon in Planck units. The punctures with large colors are, for the black hole horizon, similar to what are the fluid parcels for a classical fluid. We dub them puncels. Hence, in the fluid limit, the horizon is composed by puncels which are themselves interpreted as composed (in the sense of the tensor product) by a large number of more fundamental intertwiners. We study the spectrum of the euclidean volume acting on puncels and we compute its quantum fluctuations. Then, we propose an interpretation of black holes radiation based on the properties of the quantum fluctuations of the euclidean volume operator. We estimate a typical temperature of the black hole and we show that it scales as the Hawking temperature.

Not to my knowledge, but there's progress. In 1997, a Schwarzschild black hole in 7+1 flat dimensions could be described as a metastable array of D0-branes wrapped around the compact dimensions, for which "Hawking emission proceeds a few 0-branes at a time" (final sentence of the paper). It is difficult to adapt that method to lower dimensions (second last paragraph), but AdS/CFT came to the rescue. The price is that one works in AdS space, but it can be made to approximate flat space. Here is a recent study in 4+1 AdS dimensions - see section 3.2. In section 4.1 they discuss generalizing to 3+1 AdS dimensions; and independently, this month a paper appeared constructing non-extremal black holes in 3+1 AdS dimensions, where the compact dimensions are the manifold M111, which gives the standard model gauge group.

Demystifier and kodama
Not to my knowledge, but there's progress. In 1997, a Schwarzschild black hole in 7+1 flat dimensions could be described as a metastable array of D0-branes wrapped around the compact dimensions, for which "Hawking emission proceeds a few 0-branes at a time" (final sentence of the paper). It is difficult to adapt that method to lower dimensions (second last paragraph), but AdS/CFT came to the rescue. The price is that one works in AdS space, but it can be made to approximate flat space. Here is a recent study in 4+1 AdS dimensions - see section 3.2. In section 4.1 they discuss generalizing to 3+1 AdS dimensions; and independently, this month a paper appeared constructing non-extremal black holes in 3+1 AdS dimensions, where the compact dimensions are the manifold M111, which gives the standard model gauge group.

in terms of occam's razor, LQG's results as referenced in the paper for non-extremel hawking radiation in 4D seem simpler and more intuitive, makes more contact with established physics than strings as described by the above. hawking showed black holes have entropy and emit radiation, and LQG seems to offer the microstates that account for both more simply than strings.