Timeline for How can one reconcile the temperature of a black hole with asymptotic flatness?
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5 events
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| Aug 28, 2011 at 20:51 | comment | added | Ron Maimon | -1: If the whole universe is filled with radiation at a given temperature, how can you expect it to be asymptotically flat? This answer is totally wrong. | |
| May 28, 2011 at 10:27 | comment | added | Daniel Grumiller | Yes, to talk about Hawking temperature in the first place we should assume the semi-classical approximation to be valid. Then backreaction effects will be small, the Hawking flux will be stationary to leading order, and a Bondi mass can be well-defined. Regarding thermal equilibrium there are the standard issues with negative specific heat, that can be resolved by putting the black hole inside a cavity, which provides a heat bath. If the cavity is sufficiently close to the horizon you have positive specific heat. However, then it is meaningless to talk about asymptotic observers. | |
| May 28, 2011 at 8:17 | comment | added | Columbia | Thinking about it more. I think you are talking about using the quasistatic approximation here, before the hole becomes Planckian (and the approximation loses its power and quantum gravity becomes important) | |
| May 28, 2011 at 8:02 | comment | added | Columbia | Once you start asking questions about the global backreaction effects (important roughly when M is of order 1 eg the Planck mass), its not clear to me how you define a concept like the Bondi mass. Intuitively what you say makes good sense, but I don't know of a way to see that precisely. Also its clear that thermal equilibrium no longer makes sense when you enter the regime where backreaction effects are important and its thus difficult to talk about a Hawking temperature. | |
| May 28, 2011 at 7:25 | history | answered | Daniel Grumiller | CC BY-SA 3.0 |