What are the differences between Volovik & Wen theories?

[ensabah6]

Both purport to make use of condense matter- models to model fundamental physics.

What are the differences and which seems more promising?

[atyy]

I believe Wen would like emergent fermions, while Volovik wouldn't mind fundamental fermions. Neither is promising, though both are inspiring and worth studying. I think AdS/CFT is a working example for emergent gravity in some universes (not ours) that is very much in the spirit of condensed matter. So we have examples of emergent gravity (AdS/CFT) and emergent QED and QCD (Levin and Wen), but no examples of emergent chiral fermions (yet?).

[ensabah6]

I believe Wen would like emergent fermions, while Volovik wouldn't mind fundamental fermions. Neither is promising, though both are inspiring and worth studying. I think AdS/CFT is a working example for emergent gravity in some universes (not ours) that is very much in the spirit of condensed matter. So we have examples of emergent gravity (AdS/CFT) and emergent QED and QCD (Levin and Wen), but no examples of emergent chiral fermions (yet?).

I've wondered about the relevance of AdS/CFT to our universe, esp as a fundamental theory

Would it be possible to combine Wen's emergent QED QCD on a spin network lattice, with Bilson-Thompson braided to get emergent chiral fermions?

[atyy]

I've wondered about the relevance of AdS/CFT to our universe, esp as a fundamental theory

Would it be possible to combine Wen's emergent QED QCD on a spin network lattice, with Bilson-Thompson braided to get emergent chiral fermions?

He, he - I don't know - I'd publish it if I knew :smile:

[ensabah6]

He, he - I don't know - I'd publish it if I knew :smile:

Do spin foam spin networks have the properties with which Wen's QED QCD can emerge?

And are "twists" in spin networks correspond to chiral fermions?

[heinz]

Would it be possible to combine Wen's emergent QED QCD on a spin network lattice, with Bilson-Thompson braided to get emergent chiral fermions?

It seems that this combination describes what Schiller is doing on http://www.motionmountain.net/research/ In his "strand" model/conjecture, he deduces emergent chiral fermions made of braided tangles. He uses the same trick as Bilson-Thompson to show that there are only three particle generations. But Schiller predicts no Higgs - hmm...

[ensabah6]

It seems that this combination describes what Schiller is doing on http://www.motionmountain.net/research/ In his "strand" model/conjecture, he deduces emergent chiral fermions made of braided tangles. He uses the same trick as Bilson-Thompson to show that there are only three particle generations. But Schiller predicts no Higgs - hmm...

Wen offers emergent Higgs using a local bosonic theory.

Are neutrinos the only chiral fermions Wen is unable to account for?

[John86]

That is your personal view i think Atvy, although you also know that the condensed matter physics field, is the most tested and confirmed perhaps field in physics. For me it makes sence because it ultimately also inhabits quantum mechanics as emergent. And thereby leaves out anything fundamental.

[atyy]

That is your personal view i think Atvy, although you also know that the condensed matter physics field, is the most tested and confirmed perhaps field in physics. For me it makes sence because it ultimately also inhabits quantum mechanics as emergent. And thereby leaves out anything fundamental.

I guess you are disagreeing with the part where I said it's not promising? Well, these are my favourite approaches, so I say they are not promising :smile:

[John86]

Wen offers emergent Higgs using a local bosonic theory.

Are neutrinos the only chiral fermions Wen is unable to account for?


Yes that's interesting Wen says fundamental particles arise from the collective behaviour of bossons. This is wat Wen exactly says.

This paper uses a particular emergence approach: we
try to obtain everything from a local bosonic model. The
detail form of the bosonic model is not important. The
important issue is how the bosons (or the spins) are organized
in the ground state. It is shown that if bosons
organize into a string-net condensed state, then photons,
electrons and quarks can emerge naturally as collective
motions of the bosons.12–15 In this paper, we will find an
organization of bosons such that the collective motions
of bosons lead to gravitons.

http://arxiv.org/PS_cache/gr-qc/pdf/0606/0606100v1.pdf

My idea is that Volovik goes a step further then Wen, But Wen digs deeper. Although if you read Volovik's Book "the universe in helium droplet" you get a really good idea what Volovik envisions. The book goes much deeper than his papers usualy

[ensabah6]

Yes that's interesting Wen says fundamental particles arise from the collective behaviour of bossons. This is wat Wen exactly says.

This paper uses a particular emergence approach: we
try to obtain everything from a local bosonic model. The
detail form of the bosonic model is not important. The
important issue is how the bosons (or the spins) are organized
in the ground state. It is shown that if bosons
organize into a string-net condensed state, then photons,
electrons and quarks can emerge naturally as collective
motions of the bosons.12–15 In this paper, we will find an
organization of bosons such that the collective motions
of bosons lead to gravitons.

http://arxiv.org/PS_cache/gr-qc/pdf/0606/0606100v1.pdf

My idea is that Volovik goes a step further then Wen, But Wen digs deeper. Although if you read Volovik's Book "the universe in helium droplet" you get a really good idea what Volovik envisions. The book goes much deeper than his papers usualy

I infer then that for Wen bosons are fundamental, Volovik thinks fermions are fundamental. Either through string nets or emergent physics, can give rise to gauge symmetries and SM particles

Do you know if spin networks can give rise to bosons organize into a string-net condensed state or fermions analogous to super-fluid He3?

[heinz]

Both purport to make use of condense matter- models to model fundamental physics.

What are the differences and which seems more promising?

Volovik is presenting a high-level analogy (nasty people would call him a crackpot) whereas Wen has some original, good and promising ideas.

[ensabah6]

Volovik is presenting a high-level analogy (nasty people would call him a crackpot) whereas Wen has some original, good and promising ideas.

So where does Group Field Theory fit in?

Oriti offers to model spin-networks on a fat graph that gives rise to a He3 like superfluid.

i.e arxiv.org/abs/gr-qc/0607032

http://arxiv.org/abs/0710.3276


We put forward a more specific, albeit still very much tentative, proposal for the relevant phase of the GFT corresponding to the continuum: a Bose-Einstein condensate of GFT quanta. Finally, we sketch how the proposal may be realised and its effective dynamics could be extracted in the GFT setting and compared with continuum gravity theories.



Crackpot?

[heinz]

So where does Group Field Theory fit in?

Oriti offers to model spin-networks on a fat graph that gives rise to a He3 like superfluid.
i.e arxiv.org/abs/gr-qc/0607032

Crackpot?

I said that Volovik's work was questionable - I have not read Oriti well enough to say something sensible about it.

[ensabah6]

I said that Volovik's work was questionable - I have not read Oriti well enough to say something sensible about it.

There's quite a bit of discussion about Group Field theory in LQG. But I admit I don't understand it nor know how promising it is.

BUT if it does model spacetime as a superfluid perhaps then either or both Volvovik, Wen, or Bilson Thompson emergent schemes might be the way forward

[atyy]

Wen has an interesting diagram on the last slide of http://dao.mit.edu/~wen/talks/09Dresden.pdf

I like the links "AdS/CFT-Emergent gravity-long range entanglement-tensor category".

I'm trying to figure out where GFT fits in too. I think these papers indicate that something very interesting will come out of it (Thanks marcus for your biblio!).
Freidel, Gurau, Oriti http://arxiv.org/abs/0905.3772
Magnen, Noui, Rivasseau, Smerlak http://arxiv.org/abs/0906.5477
Tanasa, http://arxiv.org/abs/0909.5631

But I have nothing more than gut feeling at this point. My only indicator is sociological. Tanasa cites Markopoulou's work http://arxiv.org/abs/gr-qc/0203036 and Markopoulou has been trying to link up quantum graphity http://arxiv.org/abs/0801.0861 with Levin and Wen's work, and I'm believe this is all one coherent "sniff" on her part :smile: