LizR wrote:
On 11 November 2014 10:32, Bruce Kellett <bhkell...@optusnet.com.au
<mailto:bhkell...@optusnet.com.au>> wrote:
LizR wrote:
OK, so are you saying that the formation of bound states like
nucleons has no bearing on the existence of an AOT?
It certainly doesn't play a role in the origin of the AoT. Formation
of bound states is just a routine physical process that follows
conventional dynamical laws, including the second law of
thermodynamics. Since the second law governs these processes, they
are subject to an AoT.
You appear to be assuming the AOT in order to explain something that
emerged from a state in which there was no distinct AOT. The quark
soup starts in a high energy, essentially time-reversible state (any
nucleons that happen to form sill rapidly fall apart again) - how can
the 2nd law apply at that point?
I think we have covered this. The quark-gluon plasma is a thermal state
of only those degrees of freedom -- other degrees of freedom,
particularly gravitational, are not thermalized, so it is not a state of
maximum entropy. It is, in fact, a low entropy state compared with what
might be expected -- we could have a soup of black holes for instance,
which would have the same energy density but vastly higher entropy. Why
do we not have such a state? That is the past hypothesis -- things
started in an unusually low entropy state.
If the universe were not expanding, and hence cooling the initial
plasma, then the gravitational degrees of freedom would gradually become
excited, and eventually fully thermalized. The entropy would rise
throughout this process, even though no expansion is hypothesized. The
second law applies because the state has a much lower entropy than other
states which are equally likely. The second law is there in the
statistics of the degrees of freedom -- it does not have to 'emerge'
from anywhere.
Bruce
The 2nd law is emergent, as I think we all agree, and we're trying to
explain how it might have emerged from time-symmetric physics. The
transition from a plasma in which free quarks are interacting in an
essentially time symmetric manner to a cloud of nucleons looks like a
step on the way to doing that.
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