What is Space made of?

[Mordred]

That would be a useful project for me to help others. I may just do that

[StringJunky]

That would be a useful project for me to help others. I may just do that

Definitely. it would be useful to you as well in consolidating what you've learnt in communication terms as well as the physics. i think it would be good if you aim for the same sort of audience and in the spirit that Sean did in that video but in written form. I'm sure you are quite capable of writing for a mathematically-capable audience as well but I think they are probably well catered for.

Edited July 9, 2017 by StringJunky

[Mordred]

Whenever I sit down to write any article including the two in my signature I end up learning 😁.

 

Site Articles (Articles written by PF and Site members)

 

http://cosmology101.wikidot.com/redshift-and-expansion

http://cosmology101.wikidot.com/universe-geometry

 

The top article is my first attempt at writing site articles. Took me 6 months to finally complete.

 

The second one went smoother only 2 and I find its better written.

 

The trick is removing ambiguous sentences etc. Its amazing how simple it is to miss imply.

 

(last one has a page two link at bottom of page)

 

Edit: Lol though there was a huge debate on the Cosmological redshift and gravitational redshift on the viability of being treated one and the same. Listening to numerous Ph.D's arguing the pros cons was definetely a learning experience. Took P. Allen and I some effort to reword the article to allow the possibility of both.

 

P.Allen and I took on sections of the first paper then blended in the two different writing styles.

 

I learned a lot since writing the first so have been considering rewriting the first article.

Edited July 9, 2017 by Mordred

[Handy andy]

Another question boardering on the surreal.

 

In terms of space or additional dimensions have you any insight on quantum entanglement.

 

If a field fluctuation creates it own space from nothing, are all points in space connected via another dimension or nothing.

 

Are all points in space created by fields connected in some way.

 

How many dimensions has space.

[Mordred]

Another question boardering on the surreal.

 

In terms of space or additional dimensions have you any insight on quantum entanglement.

 

If a field fluctuation creates it own space from nothing, are all points in space connected via another dimension or nothing.

 

Are all points in space created by fields connected in some way.

 

How many dimensions has space.

A little scattered, but one or two good questions in this.

Are all points in space created by fields connected in some way.

 

 

Don't think of one creating the other.

 

In expansion the fields can affect volume change. You don't create space, as space has no substance that needs creating.

 

If a field fluctuation creates it own space from nothing, are all points in space connected via another dimension or nothing.

By this referring to universe from nothing models describing the quantum process in the expansion of our universe from BB.

 

Other than the caveat above (I never liked the term "space created" too misleading) for the reasons above.

How many dimensions has space.

Ok this is s very important question.

 

In physics a dimension is an independant value. By this I mean this variable etc can change without changing any other values.

 

This is also called a "degree of freedom"

 

Now in mathematical treatments it is preferable to reduce a system to the minimal number of degrees of freedom as possible.

 

An example is "Hilbert space" which reduces the degrees of freedom to 2 dimensions. It does so in essence by charge vectors and symmetry groups.

 

So for string theory ext the higher dimensions correspond to effective independant degrees of freedom a system has.

 

Here is a classic example. A robot arm that only move up and down has 1 degree of freedom. It cannot move up without affecting the distance from the bottom.

 

Now if that arm can move up/down and left/right. We have an additional degree of freedom. Now we can also spin that arm without affecting the other ranges of motion.

 

So now spin is a degree of freedom that requires 2 dimensions to mathematically define. (angular momentum)

Edited July 9, 2017 by Mordred

[Handy andy]

If I understood correctly space is created by fields virtual or otherwise which expand the space they occupy accelerating the expansion of the universe or the distance between galaxies. With no fields there is no space, what no space is or nothing is, is interesting and possibly just philosophical. I understand information is transmitted via quantum entanglement instantly, and not limited by c. If two points were connected by some other dimension could the distance be zero in another dimension between the points. I think last time I read a popular physics book on string theory there was 13 dimensions that could unfold.

[Mordred]

The above not exact isn't inaccurate enough to correct. Heuristically describing fields as creating space is commonly written in literature just keep in mind space is just the volume.

 

As for the Entanglement information isn't exchanged faster than c.

 

That is a pop media misnomer that I would prefer to help you understand under a new thread in QM forum as its a bit off topic on this thread.

 

Yes string theory has 13 dimensions. (effective degrees of freedom), There is also embedded mathematical geometry states (local etc)

Edited July 9, 2017 by Mordred

[Strange]

To me, when I hear or read the word nothing ; i cannot think other of an other particle that i have called Nothing..and it's a ''Cube''. The reason Why? is that ,when in my head i shrink the 8 corners back to the center of the cube i do not see the Cube any more So! what if empty space, we so call, was replaced by cubes that cannot be detected and nor seen .

But the same is true of a (simpler) tetrahedron or an icosahedron or a sphere. So there is no reason to visualise it as a cube.

But..Volume require boundary. So what is boundary ? is it a time limit?... containing Energy ? and if so matter must be a part of it .

It doesn't require a boundary. If the volume is infinite, for example. But even if the universe is finite, it is assumed to have no boundary. (This is easier to imagine in 2 dimensions, the surface of a sphere, for example. Or a cube, if you must.)

[Handy andy]

Thankyou. I have not checked to see if a thread on entanglement exists, but will look forward to the thread. Do you have an opinion on how many spacial dimensions there may be. Are the string theorists just talking about mathematical dimensions for convenience, rather than actual spacial dimensions.

[Mordred]

Combination of both. Your three spatial dimensions are always included but under the global geometry. String theory under groups adds mathematical dimensions to separately define smaller volumes under transformations for different overlapping fields. In essence different embedded geometries each describing a different field dynamic.

 

The key is symmetry transformations.

 

For example Kaluzu-Klien has you relativity degrees of freedom.

 

(ct,x,y,z) Now Kaluzu adds electromagnetic charge to the above. Making the above 5D.

 

If you add the strong force you need a minimal 3 degrees of freedom to define the interactions of the quark family.

 

So now we have 8.

 

Now add the weak force for another 3.

 

11 dimensions.

 

Under groups the above is SO(3)×SU(2)×U(1). This is the majority of the dimensions in String theory but not all

Edited July 9, 2017 by Mordred

[Handy andy]

Thankyou very much for the response apologies for the pop physics derived questions, originating from expensive string theory books.

 

I understand degrees of freedom having done some modelling before, sorry not on a cat walk more of a non linear mathematical nature involving magenetic circuits.

 

I have a question with reference to your previous answer. I may have missed the overwhelming relevance of what you initially wrote, and never followed up with the correct question..

 

Paraphrasing the Big bang or quantum foam causes the expansion of space. Without a field virtual or otherwise there is no space. Quantum foam is constantly expanding space. Gravity is caused by the contraction of space ie the reduction of fields or quantum foam that creates space.

 

DOES Mass shrink the space around it, by absorbing or calming the quantum foam which causes the expansion of space. BIG QUESTION MARK. (Sorry portuguese key board I cant find the key for question mark).

 

Is a graviton required under QFT

[Mordred]

Yes and no using strictly mass.

 

As matter collapses into large scale structures, it concentrates matter locally. This in turn reduces mass density globally so that the universe will in fact expand instead of collapsing as the global mass density decreases.

 

What you need is another set of relations.

 

This being potential energy vs kinetic energy. Every particle has an energy density to pressure relation. (matter being p=0)

 

if the inherent kinetic energy of your particle contributors is greater than the potential energy of gravity the universe will expand. It will collapse if the average gravitational potential exceeds the inherent kinetic energy of your contributors..

 

Here is a link on equations of state (cosmology). Read the link first, then read the universe geometry article above.

 

https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology)

 

The critical density formula gives the point where an expanding universe will start collapsing (at least prior to discovering DE).

 

In essence it is the universe thermodynamic relations that dictate how our universe evolves. gravity is only a part of the equations.

Edited July 10, 2017 by Mordred

[Handy andy]

Thank you for those links I will take some time absorbing them.

 

I do have further series of questions with reference to the big bang theory and cosmic background radiation. This may get relegated to speculation.

I read another pop physics book some time ago based on the work of Alfen a nobel prize winning plasma physicist called "the big bank never happened", so this is not completely my idea.

 

Is background radiation only evidence for an expanding universe, and not the origins off all matter in some huge bang from 10^-43 seconds onwards, is this why it is almost uniform 2.5 kelvin throughout space and it does not appear to be cooling?

 

What I am thinking is quantum matter appears and disappears in space continuously gradually increasing and expanding space, causing the expansion of space. This in turn perhaps on occasion produces real matter that coalesces to form planets, or suns that can supernovae and eject heavier particles into space overtime etc.

 

Is the amount of energy in the universe slowly increasing due to quantum fluctuations expanding space. If a fixed volume of space is at 2.5kelvin, when the space in it expands beyond the fixed volume should the temperature not reduce within the fixed volume of space.

 

Is the lifetime of fundamental particles in a zero g environment increased as evidenced by the muon decay time, does this also apply to quantum matter.? Does more quantum matter exist in space than in a gravitational environment, ie theoretical DE perhaps.

 

Sorry for the stream of questions

Edited July 11, 2017 by Handy andy

[Mordred]

Lets see at [latex]10^{-43}[/latex] the temperature would be around [latex]10^{19} [/latex] The estimated number of particles using the Bose-Eistian Boltzmannn statistics is [latex] 10^{90}[/latex] particles.

 

inflation then occurs solving the flatness problem and horizon problem. Giving us our uniform temperature distribution.

 

Inflation causes a rapid supercooling due to the ideal gas laws. ( an increase in volume will lower temperature as the average density decreases).

 

When inflation slow rolls to a stop there is a super reheating. This removes any further anistropy.

 

When the temperature drops below 3000 kelvin atoms start to form giving us our CMB.

 

So key evidence for BB. Uniform distribution via inflation, universe cooling= evidence of expansion. Correct predicted percentage of hydrogen, lithium etc= nucleosynthesis evidence.

 

Hows that for a quick coverage to answer your questions above. If you want greater detail feel free to start a new thread in astronomy forum. The number of particles remain approximately the same but the types of particles and mixture changes.

 

https://arxiv.org/abs/1304.4446

What we have leaned from Observational Cosmology." -A handy write up on observational cosmology in accordance with

LCDM

https://arxiv.org/abs/astro-ph/0409426

 

overview of Cosmology Julien Lesgourgues

 

Here is some free articles on Cosmology

Edited July 11, 2017 by Mordred

[Handy andy]

When inflation slow rolls to a stop there is a super reheating. This removes any further anistropy.

 

When the temperature drops below 3000 kelvin atoms start to form giving us our CMB.

 

So key evidence for BB. Uniform distribution via inflation, universe cooling= evidence of expansion. Correct predicted percentage of hydrogen, lithium etc= nucleosynthesis evidence.

 

Hows that for a quick coverage to answer your questions above. If you want greater detail feel free to start a new thread in astronomy forum. The number of particles remain approximately the same but the types of particles and mixture changes.

 

http://arxiv.org/abs/1304.4446 :"Whatwe have leaned from Observational Cosmology." -A handy write up on observational cosmology in accordance with the LambdaCDM model

http://arxiv.org/pdf/hep-ph/0004188v1.pdf:"ASTROPHYSICS AND COSMOLOGY"- A compilation of cosmology by Juan Garcıa-Bellido

http://arxiv.org/abs/astro-ph/0409426 An overview of Cosmology Julien Lesgourgues

http://arxiv.org/pdf/hep-th/0503203.pdf"Particle Physics and Inflationary Cosmology" by Andrei Linde

http://www.wiese.itp.unibe.ch/lectures/universe.pdf:" Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

 

 

Yep very quick answer and no I didn't follow all of it But Thank you for the links, I will download the pdf's and add them to my E reader for later digestion. Night watch in the middle of an ocean is an excellent place to do cosmology.

 

Edit Only the link to Physics and Inflationary Cosmology" by Andrei Linde link works. This may be due to the fact I am in Portugal at the moment rather than UK or US, which is sometimes a problem.

Edited July 11, 2017 by Handy andy

[Mordred]

If some of the links didn't parse correct use my signature the links are on my site page.

 

http://cosmology101.wikidot.com/

Edited July 11, 2017 by Mordred

[Itoero]

According to Leonard Susskind entanglement keeps space together.

When you disentangle two regions in space then there appears energy which distorts the space.

Energy is mass and mass is a source for a gravitational field which implies a curvature and distortion of the geometry of space by increasing the distance in space or in a sense the volume of space.

After disentangling those regions, the released energy will be radiated away and the entanglement will restore itself...and the geometry of space will also be restored.

 

You can turn this around. By increasing entanglement between two regions you reduce the distance in space and you can pull those regions together.

What's your opinion on this?

 

[Mordred]

He is refferring to a particular model called holographic entangled spacetimes via the holographic principle using ADS/CFT theory.

 

Numerous physicists support ADS/CFT others don't. ADS is Anti-Desitter. With CFT being conformal field theory. Which is a particular higher dimension treatment.

 

The model is mathematically viable, with some support. Its one possibility but as of yet does not have any strong evidental support.

 

This has similarities but is a bit different from particle entanglement. (Though similar mathematics has been shown that particle entanglement may also involve ADS/CFT.) in a similar manner.

 

 

In essence [latex]\mathcal{H}=\mathcal{H}_{qubit}\otimes\mathcal{H}_{qubit}[/latex]

 

You have three Hilbert spaces 2 which are disentangled summing to the entangled spacetime L.H.S of equal sign.

 

the two [latex]\mathcal{H}[/latex] on the R.H.S follow the degrees of defined by the Hilbert spaces defined by

 

[latex]\frac{1}{\sqrt{2}}(|00\rangle+|11\rangle)[/latex]

 

Which is your spin up spin down states. for spin 1/2 statistics. Hilbert space under QM. I wouldn't think of this as different spaces as in a hidden dimension etc. This actually describes degrees of freedom) when the spin up and spin down degrees of freedom are entangled you have the LHS state. CFT tries to connect the spin 1/2 states to geometry via the holographic principle.

 

It is a fancy way to describe how states becomes correlated. Yes this does show a possible descriptive in regards to Bell's inequality vs hidden dimensions. (care must be taken on how dimension is defined).

 

There is huge misleading confusions of what this model mathematically describes. Simply due to its complexity. How do you explain IR and UV cutoff, holonomy, bifarcations, tensor degrees of freedom etc to the public?

 

Simply put these spaces are restricted to the quantum scale. At the quantum scale the bifarcations of Hilbert spaces can occur with the density matrix being defined by the correlation function in the short and long range cutoffs defined by the IR and UV divergences (infrared and ultraviolet) S matrix cutoffs. Where each bifarcation is a cauchy foliation on our Lorentzian spacetime.

 

lol try to explain that last paragraph to the public. Add to that the cutoffs and correlation functions are probability functions.

 

Might help if you associate each state as a phase. The Hilbert space being the map of influence strength of each individual phase/state. (yes were dealing with waveforms/excitations under Hilbert spaces). Hilbert spaces is an excellent tool to describe sinusoidal waveforms.

 

As you can see this model treats particles as field excitations. As it must involve QFT. Each Hilbert space corresponds to a field phase state.

Edited July 11, 2017 by Mordred

[Itoero]

Ok, thx for the explanation.

There are imo 2 things that point to the validity of holographic entangled space time, the Kondo effect and the hypothesis that entanglement holds DNA together.

-In the Kondo effect, resistivity in a metal rises when it reaches 0 K because of an impurity in the metal. It has been shown that entanglement between conducting electrons or of an electron with its environment causes the rise in resistivity...this many-body entanglement lies at the heart of the Kondo effect. This implies that the entanglement inhibits movement of conducting electrons. This is imo only possible if there is some sort of attraction force between electrons and its environment which inhibits movement. So there is a kind of attraction force between entangled bodies, you might call this quantum magnetism.  Another way of saying this is that entanglement reduces the volume between bodies, like Leonard Susskind explained in the video.  http://www.nature.com/articles/ncomms12442  https://phys.org/news/2011-06-electrons-entangled.html#jCp

-A theoretical model suggests that quantum entanglement  holds DNA together, it prevents DNA from breaking apart. Each nucleotide in a base pair is oscillating in opposite directions, this occurs as a superposition of states, so that the overall movement of the helix is zero. In a purely classical model of DNA the helix would vibrate and shake itself apart. So quantum effects are responsible for holding DNA together. There is Quantum Entanglement between the electron clouds of nucleic acids in DNA. This shows there is a kind of attraction force between entangled bodies or between entangled electronclouds....quantum magnetism...just like in the Kondo effect and like Susskind explained...although he did not call it quantum magnetism.         https://www.technologyreview.com/s/419590/quantum-entanglement-holds-dna-together-say-physicists/  https://arxiv.org/abs/1006.4053

Spin-entangled electrons might be necessary for this quantum magnetism.

 

What do you think of this? It points to the idea that entanglement holds space together. Space is then volume between entangled particles.

 

Edited July 26, 2017 by Itoero

[Mordred]

Ok I will not fault you for following and supporting the holographic principle via ADS/CFT. It is a viable possibility however I would like to spend some time after work showing you how ADS/CFT works in cosmology applucations which your last post doesn't particularly apply.  

Hopefully once I detail ads/cft after work you will see why,

[Mordred]

Your last post will be extremely difficult to explain under the holographic principle and how CFT would treat the Kondo effect.  I guess the only way is to first clear up what is meant by ADS/CFT ..anti_Desitter/conformal field theory.  This very title has tremendous mathematical meaning and encompasses a range of models. Then in order to tie that in with Kondo cutoffs under conformal theory I need to explain the coordinate transformations for the holographic surface under the Penrose diagrams. All this before we can reasonably be on the same page...lol. Note hadn't gotten to entanglement yet..

OK lets start with Anti Desitter spacetimes. Well in essence an anti-Desitter spacetime is one where the curvature term is negative.   Guage transformations anticommute rather than commute.

https://en.wikipedia.org/wiki/Anti-de_Sitter_space

this wiki covers enough of the basics but in essence its a negative curvature with a cosmological constant.  Under ADS/CFT this is your boson fields.  Now conformal is rather tricky to explain under the above.  What is conformal well conformal is the transformations that leaves the size of the angles between corresponding curves unchanged. Which differs significantly to scalar transformations. Well lets just jump to conformal geometry

https://en.wikipedia.org/wiki/Conformal_geometry

lets stop here for a bit let me know if you have questions on this before we approach LSZ cutoffs as applied to your holographic surface.

My apologies for taking this approach but I honestly cannot see how I can answer your last post as to how QFT handles Kondo effect as opposed to ADS/CFT treatment unless I know you understand how the two treats the geometry of spacetime. One needs to understand the guage groups, and differences in transformations and rotations. (Especially since Kondo effect uses path integrals under feyman rules. Not to mention the coordinate transforms under the differences in coordinate systems ie tortoise, Kruskal etc..

(PS. I takes a ton of preliminary work to even begin to comprehend ADS/CFT properly)

 

 

Edited July 27, 2017 by Mordred

[Itoero]

Where does the -1 curvature comes from? Does it have any experimental value?

And are there quantum gravity models that concern 0 or +1 curvature?

Edited August 1, 2017 by Itoero

[Mordred]

  In the case of ADS/CFT the Schwartzchild metric.

Gravity locally has Lorentzian symmetry relations the inherent in vector commutations. The SO(3.1) Lorentz group is often modelled as negative curvature. ADS/CFT applies this signature choice to the Lorentz group above. Here is a decent coverage of antiDesitter under group relations.

https://www.google.ca/url?sa=t&source=web&rct=j&url=https://arxiv.org/pdf/hep-th/9805087&ved=0ahUKEwiYzpKB9bfVAhUJ4mMKHTI7CVsQFgg4MAQ&usg=AFQjCNGu1uY87efqxPD7YuCUaARv7VYwEQ

 

Anti-Desitter actually originated in GR and the FLRW metric. ADS/CFT and the previous curvature symmetries under groups follow the same relations in terms of curvature relations being modelled.

One has to be careful on what is the cause of curvature change ie there are differences between curvature of a commoving volume as opposed to a static metric. FLRW (LCDM) cosmology and GR applications respectively.

All spacetime curvature metrics will determine curvature by the scalar modelling kinetic/potential relations or often energy/density vs pressure relations following its equations of state.

[latex]w=\frac{\rho}{p}[/latex]

https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology)

see last formula for the scalar modelling relations. Coincidently QFT uses that same precise formula.

In the case of point mass Centre of mass systems the negative signature is used to identify a centre of mass vector field. This signature is also reflected under gaussian distributions of multi particle COM systems

As this thread is about spacetime tomorrow I will add the curvature terms to the metric tensor. It will help better understand Lorentz symmetry groups  SO(1,n) though it will also help in other groups such as SU(n)

Edited August 2, 2017 by Mordred

[YhwhRael]

The universe is an atom.

The atoms of your body are universes.

[Strange]

2 hours ago, YhwhRael said:

The universe is an atom.

The atoms of your body are universes.

Nonsense.