
#1
Oct1013, 03:00 PM

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I understand (I may be wrong) that the highest density material is that of a quarkgluon plasma, such as the interior of a neutron star. Is there an upper limit to this density and is it known?




#2
Oct1013, 03:31 PM

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Thanks
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Try Googling "quark phase diagram" for some interesting pictures!




#3
Oct1113, 03:30 AM

P: 188

According to our current understanding a black hole will form at some point if you keep increasing the density. The density where this happens would then be the upper limit for the density (and we are far from any such limit at today's colliders). Strongly interacting matter at these high densities is a question of current research. Some keywords to look for are "quark star", "quark matter", "color superconductivity", "colorflavor locking" and "QCD phase diagram".




#4
Oct1113, 10:34 AM

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density of quarkgluon plasmaStrange Quark Matter and Compact Stars http://arxiv.org/abs/astroph/0407155 



#5
Oct1113, 06:40 PM

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General relativity predicts that inside a black hole everything gets condensed to a point of infinite density. If there is an upper limit to the density of matter, then there would be a contradiction. 



#6
Oct1313, 09:34 AM

P: 604

'The maximum density of stable objects in hydrostatic equilibrium is 10^{16} g/cm^{3}. This limit applies to any macroscopic object composed of standard model fermions' which works out at 10 billion tonnes per cm^{3}. Hypothetical Preon degenerate matter is suppose to occur at densities around 10^{20} g/cm^{3}. Though I always thought that once inside the Schwarzschild radius, the world lines became spacelike and there is no stable radius so no matter how much pressure the degenerate matter might exert, r is temporal and will not 'hold' and it's this that predicts the singularity (though in the case of the rotating black hole, timelike world lines are reinstated beyond the Cauchy horizon and matter may still exist in some form). 



#7
Oct1313, 10:01 AM

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A high density without a black hole is possible if the object is small enough. 



#8
Oct1313, 02:44 PM

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#9
Oct1313, 02:50 PM

P: 188

Well, that's not really news is it? We have known for a long time that we can't describe phenomena where a quantized theory of gravity is needed. Hence the big interest in creating such a theory.
In any case, quantum gravity does not have much to do with the quarkgluon plasma, so regardless of what the density is in the quarkgluon plasma it has small, if any, impact on quantum gravity research. 



#10
Oct1313, 03:10 PM

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I don't see why there should be an upper limit on density of small objects, though such density might be very transitory. 



#11
Oct1413, 03:07 PM

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Above description describes the structure of a neutron star. It says that the deep interior may be a quarkgluon plasma. 



#12
Oct1513, 08:53 AM

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There is no contradiction. The limit is for the density of stable matter in hydrostatic equilibrium. These conditions do not apply to interior of a black hole.




#13
Oct1513, 03:54 PM

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#14
Oct1513, 04:07 PM

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General relativity works fine for the interior, excluding the center.




#15
Oct1613, 10:28 AM

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#16
Oct1613, 02:37 PM

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#17
Oct1613, 02:47 PM

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