Friday, December 03, 2004

Quantum Microstates: Gas Molecules in the Presence of a Gravitational Field

Andy Strominger:
This was a field theory that lived on a circle, which means it has one spatial dimension and one time dimension. We derived the fact that the quantum states of the black hole could be represented as the quantum states of this one-plus-one dimensional quantum field theory, and then we counted the states of this theory and found they exactly agreed with the Bekenstein-Hawking entropy.


I do not know of many who could not have concluded that microstates would have been something of an issue, as one recognizes this focus towards cosmological considerations. One aspect of Einstein’s general relativity, helped us recognize the value of gravitation that is extremely strong in situations where energy values are climbing. We had to look for these conditions and work them out?



Strominger: That was the problem we had to solve. In order to count microstates, you need a microscopic theory. Boltzmann had one–the theory of molecules. We needed a microscopic theory for black holes that had to have three characteristics: One, it had to include quantum mechanics. Two, it obviously had to include gravity, because black holes are the quintessential gravitational objects. And three, it had to be a theory in which we would be able to do the hard computations of strong interactions. I say strong interactions because the forces inside a black hole are large, and whenever you have a system in which forces are large it becomes hard to do a calculation.

The old version of string theory, pre-1995, had these first two features. It includes quantum mechanics and gravity, but the kinds of things we could calculate were pretty limited. All of a sudden in 1995, we learned how to calculate things when the interactions are strong. Suddenly we understood a lot about the theory. And so figuring out how to compute the entropy of black holes became a really obvious challenge. I, for one, felt it was incumbent upon the theory to give us a solution to the problem of computing the entropy, or it wasn't the right theory. Of course we were all gratified that it did.


If we did not have some way in which to move our considerations to the energy states that existed in the beginning of this universe what other measures would you use? How would you explain a cyclical model that Neil Turok and Steinhardt talked about and created for us?

Is this a predictive feature of our universe that had to have some probablity of expression and mathematically, if one wanted some framework, why not throw all things to the wind and say, Pascal's triangle will do?:)

The animation shows schematically the behavior of the gas molecules in the presence of a gravitational field. We can see in this figure that the concentration of molecules at the bottom of the vessel is higher than the one at the top of the vessel, and that the molecules being pushed upwards fall again under the action of the gravitational field.

One had to have some beginning with which to understand what could have emerged from such energy configurations. If such energies are concentrated and found to bring us to the supersymmetrical values assigned on that brane, then how would cooling functions of the CMB have figured a direct result would be expressive of those same events? Was there no way to measure chaoticness. Maybe it was all Fool’s Gold?:)

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