Mordred

What is Space made of?

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Strange    2431
24 minutes ago, Handy andy said:

How would a quantum black hole compare with a big black hole? Can it absorb and emit radiation in the same way suggested by Hawking.

As far as we know. But a theory of quantum gravity might change this. 

24 minutes ago, Handy andy said:

Is space at the quantum level still viewed as smooth

There are several theories that attempt to combine GR and quantum theory where space is quantised. But all test of quantised space have shown it to be smooth.

24 minutes ago, Handy andy said:

At the quantum level could a black hole be the cause of entanglement, like a wormhole. ?

The hypothesis is that there is some fundamental similarity between wormholes (which are purely hypothetical) and entanglement. If this turns out to be the case, I expect it will be because a theory of quantum gravity gives us a different understanding of both wormholes and entanglement. 

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MigL    492

All depends on what you mean by 'quantum' Black Holes.
A quantum sized BH, could have a huge amount of energy/mass.

Assuming GR works to exceedingly small separations, then there should be no limits to the minimum size of a BH, other than extreme amounts of Hawking Radiation due to extreme temperature, and as a result, extremely short life of the BH.

But we know that isn't the case.
IIRC, intrinsic angular momentum ( spin ) conservation laws require that curved space-time has 'torsion' ( see Einstein- Cartan theory ), and this 'torsion' gives a minimum size to particles ( see Dirac's equation in a gravitational field ).
IE, quantum effects modify GR to give a limiting size to BHs. A workable Quantum Gravity Theory will go a long way to clear up matters.

The 'no limit' scenario would have made tiny BHs in the LHC ( as was feared by some ), but the 'minimum size' scenario means we need orders of magnitude greater energies than the LHC can provide in order to create tiny BHs. 

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Handy andy    26

Thanks for the replies. You can have a laugh now:)

The reason for my question is based on what I think space is perceived to be full off. Space as I understand it is absolutely full of particles (virtual and real)  waves of one form or another. Every point in space has some form of matter or gravitational potential gradient associated with it. I was wondering if a quantum black hole was a lack of something filling a point in space allowing other matter to flow in to fill the empty space.

I also was wondering about the shape of space to allow quantum entanglement to take place. I have an half baked idea that as quantum particles come into existence they create a 3 dimensional space for a short period before popping out of existence again, possibly into a black hole. Within that 3 dimensional space occupied by a quantum particle I visualise a 4th spatial dimension allowing all points in space to be directly connected to it. It occurred to me that this might be connected to a black hole. There is as you are aware a theory of black holes losing matter through a wormhole to a white hole, which as strange pointed out has never been observed. I was partly wondering if empty space (space full of quantum activity and gradients)is partly like a white hole constantly ejecting and absorbing matter and radiation.

You will be aware I don't believe in gods, unless they are misunderstood ET's :) , beginnings of time or singularities, I do however understand the concept of continual creation and destruction, spatial contraction and expansion. What I am probing around for is a way matter can violate the 2nd law of thermodynamics and come into existence, providing matter for a big bang. I view the quantum world as being a chaotic unstable interlinked system, whereby peaks in energy will I think inevitably happen resulting in quarks being produced in space. I think the production of a single quark that combines with other quarks to produce hydrogen, is far more likely than all matter suddenly appearing out of a mind boggling big bang. A Big bang might have happened in the past, but where did the matter and heat it exploded into space come from. If space produces matter, and black holes destroy or redistribute it, it kind of makes sense. 

The big bang or god as the source of all matter is a little religious for me to accept. Something was behind it and it might have been a infinite quantum entangled computing god that produced matter form the vacuum, ie made everything. 

:)

 

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Strange    2431
2 minutes ago, Handy andy said:

The reason for my question is based on what I think space is perceived to be full off. Space as I understand it is absolutely full of particles (virtual and real)  waves of one form or another. Every point in space has some form of matter or gravitational potential gradient associated with it. I was wondering if a quantum black hole was a lack of something filling a point in space allowing other matter to flow in to fill the empty space.

That is actually quite an interesting idea (although nothing to do with black holes!) You are suggesting something like the equivalent of holes in semiconductors; a point with lower energy than the vacuum (zero point) energy. I have no idea if such a thing is possible or has been hypothesised, though.

Quote

The big bang or god as the source of all matter is a little religious for me to accept.

The Big Bang is not the source of all matter. It is just a model describing the universe expanding and cooling over time.

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Handy andy    26
5 minutes ago, Strange said:

That is actually quite an interesting idea (although nothing to do with black holes!) You are suggesting something like the equivalent of holes in semiconductors; a point with lower energy than the vacuum (zero point) energy. I have no idea if such a thing is possible or has been hypothesised, though.

The Big Bang is not the source of all matter. It is just a model describing the universe expanding and cooling over time.

Thanks now I need to drag out of storage all my old semiconductor notes. :)

 

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Mordred    833
7 hours ago, Handy andy said:

Thanks now I need to drag out of storage all my old semiconductor notes. :)

 

While your at it, think about "Observer limits and range of validity within a given metric or function.

Then think about observer limits to different observers, when it comes to BH's and if you understand particles as field excitations. Think about observer limits/range of validity of the metric.

A model is only accurate within its range of validity, with field treatments observer limits is the effective cutoffs of a given metric. ( the above is needed to understand Hawking properly under different coordinate systems.

(also applies to semiconductors in the emitter/observer limits)

Edited by Mordred

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Handy andy    26
6 hours ago, Mordred said:

While your at it, think about "Observer limits and range of validity within a given metric or function.

Then think about observer limits to different observers, when it comes to BH's and if you understand particles as field excitations. Think about observer limits/range of validity of the metric.

A model is only accurate within its range of validity, with field treatments observer limits is the effective cutoffs of a given metric. ( the above is needed to understand Hawking properly under different coordinate systems.

(also applies to semiconductors in the emitter/observer limits)

Yep lots to read and believe in, maybe I will start an OU course when I stop travelling.

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