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suprised
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Bernie G said:The interesting issue is what's inside the event horizon and if it can be confirmed by observation.
That's going to be the hard part... ;-)
Bernie G said:The interesting issue is what's inside the event horizon and if it can be confirmed by observation.
Bernie G said:The above post should have read: "Not necessarily that hard to observe."
suprised said:I guess, though this seems controversial, that the infalling observer experiences a coherent superposition of fuzzball states to the effect that he notices nothing particular at the horizon. I understand, though, that he infalling observer problem seems to be the weakest point in this proposal.
What do you mean by that?atyy said:I guess in the fuzzball proposal, the microscopic state is that there is actually no event horizon?
Right - the fuzzball microstates do not have horizons.atyy said:I guess in the fuzzball proposal, the microscopic state is that there is actually no event horizon?
This is what is claimed.atyy said:And the event horizon somehow appears by coarse graining to a macroscopic outside observer?
No idea...atyy said:I'd also be interested in knowing whether http://arxiv.org/abs/1008.3439" 's ideas are consistent with fuzzball ideas.
There is a proposal for black holes in LQG which defines horizons in terms of spin networks, i.e. with pure gravity ...suprised said:This is a remark to those who believe that this problem can be solved from within pure gravity...
tom.stoer said:There is a proposal for black holes in LQG which defines horizons in terms of spin networks, i.e. with pure gravity ...
tom.stoer said:They count spin network states forming the classical horizon area. The result reprocudes the Bekenstein-Hawking-entropy plus corrections. I bet marcus has a list of publications.
What is the proton mass according to string theory? Up to how many arbitrary factors?suprised said:AFAIK up to an arbitrary factor, which means that the result is meaningless?
tom.stoer said:What is the proton mass according to string theory? Up to how many arbitrary factors?
So let's continue seriously? or polemically?
suprised said:As said we have been running a workshop on Quantum Gravity right now, which discusses this kind of questions. Tomorrow is LQG day and we will see what the LQG persons have to tell.
Sorry about that, but you started this kind of reasoning.suprised said:You start here polemics.
For extremal black holes with maximal SUSY, no Schwarzschild and no Kerr, right?suprised said:Indeed has been shown since long that in string theory the factor comes out right, to every detail.
We know that all theories including quantum gravity (including string theory) are work in progress. So of course there are open questions. Everybody in the LQG community would agree that the Imirzi parameter os one of them.suprised said:This ambiguity thus does not allow to decide whether the number of states contributing is correct or not. So this is meaningless for settling this question in LQG.
finesuprised said:As said we have been running a workshop on Quantum Gravity right now, which discusses this kind of questions. Tomorrow is LQG day and we will see what the LQG persons have to tell.
not aware of...tom.stoer said:Sorry about that, but you started this kind of reasoning.
Sure, that's the way non-perturbatively exact statements can be made without directly solving the theory.tom.stoer said:For extremal black holes with maximal SUSY, no Schwarzschild and no Kerr, right?
tom.stoer said:We know that all theories including quantum gravity (including string theory) are work in progress. So of course there are open questions. Everybody in the LQG community would agree that the Imirzi parameter os one of them.
All what I wanted to say is that there seems to be a very detailed description based on microscopic degrees of freedom which can be applied to "classical black holes". The Immirzi parameter has to be fixed, then the prediction is unambiguous. I do not see a problem to have one parameter in a theory w/o being able to derive it theoretically. You can't do that in other theories, either (QCD coupling constant / scale, GSW coupling / Fermi constant, ...)
derek101 said:if matter and anti-matter annihilate,only the expansion of time can keep them apart.thus a singularity at the center of a black hole i suggest consists of anti-matter 13.7 billion years in the past(back to the big bang)and matter 13.7 billion years into the future.the matter in the surrounding galaxy is being sucked into the future this is my understanding of space time.
I never understoof the Immirzi parameter as a multiplicative parameter for the number of states (for a given area) but always as a multiplicative constant for the (classical) area given a predefined state count. So there are two issues: is the counting correct? what's the value of the Immirzi parameter?suprised said:... Rather, because it multiplies the entropy, it directly affects how you count the number of states of the theory. Since this parameter is arbitrary, ... it is impossible to tell whether the states provided by LQG are "enough" such as to account for the microstates of black holes. Tuning the parameter to the "right" value won't continuosuly change the number of states until it matches the correct count. Rather it should be seen as a prefactor multiplying an unknown state count.
...
These facts are known to anybody working in the field, and this was also confirmed by today's discussions.
tom.stoer said:So there are two issues: is the counting correct? what's the value of the Immirzi parameter?
What was the result of the discussion with the LQG colleagues you mentioned.
I agree that there is no consensus regarding the Immirzi parameter. But we do not agree on the reasoning in general.suprised said:Well, we have had various discussions and the general consensus seems that this formula is inconclusive, with regard to the question whether the right number of states is counted. In fact the "right" value of the Immirzi parameter depends on the particular LQG model, and thus is non-universal.