Was the Big Bang a "Quantum Event"?

[gib65]

I know I'm probably misusing the term "quantum event", so here's what I understand it to mean:

 

A physical event that defies the laws of classical mechanics but is perfectly consistent with, and explainable by, the "laws" of quantum mechanics.

 

I also understand that quantum events are more likely to occur the smaller the frame of reference is - that is, as one considers phenomena at lower and lower scales, one needs more and more to take quantum mechanics into consideration in order to make accurate (or close to accurate) predictions.

 

So, then, here's my question:

 

Was the Big Bang a quantum event? I've heard from sources I forget where that it was. If the Big Bang started as all matter and energy condensed into a singularity, then you can't get any lower in scale than that, and therefore quantum events would be rampant. If it did not start from a singularity, could it be that the scale at which quantum events occur with a critical probability was higher up back then? Could that critical level have been decreasing since then, and will it continue to decrease indefinitely? Also (last question, I promise ), if the Big Bang started as a quantum event, is there really any need to question "what caused it" as so many do? That is, my thinking is that the conventional notion of "causation" only makes sense in a classical mechanics framework. In quantum mechanics, however, that term either takes on a different meaning, or has none at all.

[[Tycho?]]

I know I'm probably misusing the term "quantum event"' date=' so here's what I understand it to mean:

 

A physical event that defies the laws of classical mechanics but is perfectly consistent with, and explainable by, the "laws" of quantum mechanics.

 

I also understand that quantum events are more likely to occur the smaller the frame of reference is - that is, as one considers phenomena at lower and lower scales, one needs more and more to take quantum mechanics into consideration in order to make accurate (or close to accurate) predictions.

 

So, then, here's my question:

 

Was the Big Bang a quantum event? I've heard from sources I forget where that it was. If the Big Bang started as all matter and energy condensed into a singularity, then you can't get any lower in scale than that, and therefore quantum events would be rampant. If it did not start from a singularity, could it be that the scale at which quantum events occur with a critical probability was higher up back then? Could that critical level have been decreasing since then, and will it continue to decrease indefinitely? Also (last question, I promise ), if the Big Bang started as a quantum event, is there really any need to question "what caused it" as so many do? That is, my thinking is that the conventional notion of "causation" only makes sense in a classical mechanics framework. In quantum mechanics, however, that term either takes on a different meaning, or has none at all.[/quote']

 

Yes, the big bang was a "quantum event", by your definition. In that quantum mechanics are required to understand it. However, like a black hole, this poses a large problem for current physics. A singularity is very small, and hence dealt with by quantum mechanics. Its also very massive, and large masses are dealt with by general relativity. So both theories are required for the understanding of the big bang or a black hole, however the two theories are not compatible with each other.

 

Its actually GR that predicts a singularity to occur. But this is a very strange result, one that is likely incorrect. To understand these phenomenon a theory which combines general relativity and quantum mechanics is required, ie a theory of "quantum gravity"; this is one of the fundamental goals in physics today. Some people are trying string theory, some others loop quantum gravity (you can get Martin to tell you about that). But its slow going, and all these new theories are still on the drawing board.

 

(This is just a laymans explanation, Martin likes making posts about loop quantum gravity, so you can do a forum search for those)

http://en.wikipedia.org/wiki/Quantum_gravity

[Martin]

'](This is just a laymans explanation' date=' Martin likes making posts about loop quantum gravity, so you can do a forum search for those)

http://en.wikipedia.org/wiki/Quantum_gravity[/quote']

 

Abhay Ashtekar is a top figure in quantum gravity and he just posted a paper called "Quantum Nature of the Big Bang"

 

that would seem to address the OP question----you can get it first hand instead of by way of my or Wiki paraphrases

 

here is an arxiv search for Ashtekar

http://arxiv.org/find/grp_physics/1/au:+ashtekar/0/1/0/all/0/1

 

and it gives a list of his recent papers, plus links so you can get any you like instantly and free.

 

here is a sample of recent ones

 

 

1. physics/0605078 [abs, ps, pdf, other] :

Title: The Issue of the Beginning in Quantum Gravity

Authors: Abhay Ashtekar

Comments: 15 pages, 2 figures. History and Philosophy of Physics. Based on an invited talk at the 7th International Conference on the History of General Relativity (HGR7), "Einstein and the Changing World View of Physics, 1905-2005", held at Tenerife, Canary Islands in 2005

Subj-class: History of Physics

 

2. gr-qc/0605011 [abs, ps, pdf, other] :

Title: Gravity, Geometry and the Quantum

Authors: Abhay Ashtekar

Comments: 16 pages, 2 figures. To appear in the Proceedings of the `Einstein Century' Conference, 15-22 July, Paris, edited by J-M Alimi et al (American Institute of Physics)

 

3. gr-qc/0604013 [abs, ps, pdf, other] :

Title: Quantum Nature of the Big Bang: An Analytical and Numerical Investigation I

Authors: Abhay Ashtekar, Tomasz Pawlowski, Parampreet Singh

Comments: Revtex4, 60 pages, 19 figures. Minor changes to improve presentation, typos corrected, references added

 

4. gr-qc/0602086 [abs, ps, pdf, other] :

Title: Quantum Nature of the Big Bang

Authors: Abhay Ashtekar, Tomasz Pawlowski, Parampreet Singh

Comments: Revtex4, 4 Pages, 2 Figures. Minor changes to match the published version in Physical Review Letters

Journal-ref: Phys.Rev.Lett. 96 (2006) 141301

 

5. gr-qc/0509075 [abs, ps, pdf, other] :

Title: Quantum geometry and the Schwarzschild singularity

Authors: Abhay Ashtekar, Martin Bojowald

Comments: 31 pages, 1 figure

Journal-ref: Class.Quant.Grav. 23 (2006) 391-411