Saturday, March 26, 2011

Does high temperature super-conductivity involve a new phase of matter?

Kram sent a link to a Science Daily popular article titled "High-Temperature Superconductor Spills Secret: A New Phase of Matter?" (see also this). For more details see the article in Science.

Zhi-Xun Shen of the Stanford Institute for Materials and Energy Science (SIMES), a joint institute of the Department of Energy's SLAC National Accelerator Laboratory and Stanford University led the team of researchers, which discovered that in the temperature region between the pseudo gap temperature and genuine temperature for the transition to super-conducting phase there exists a new phase of matter. The new phase would not be super-conducting but would be characterized by an order of its own which remains to be understood. This phase would be present also in the super-conducting phase.

The announcement does not come as a complete surprise for me. For few years ago I developed the model high Tc superconductivity (see this and this) and a new phase of matter is what TGD indeed predicts. This phase would consist of Cooper pairs of electrons with a large value of Planck constant but associated with magnetic flux tubes with short length so that no macroscopic supra currents would be possible.

The transition to super-conducting phase involves long range fluctuations at quantum criticality and the analog of a phenomenon known as percolation. For instance, the phenomenon occurs for the filtering of fluids through porous materials. At critical threshold the entire filter suddenly wets as fluid gets through the filter. Now this phenomenon occurs for magnetic flux tubes carrying the Cooper pairs. At criticality the short magnetic flux tubes fuse by reconnection to form long ones so that supra currents in macroscopic scales become possible.

It is not clear whether this prediction is consistent with the finding of Shen and others. The simultaneous presence of short and long flux tubes in macroscopically super-conducting phase is certainly consistent with TGD prediction. The situation depends on what one means with super-conductivity. Is super-conductivity super-conductivity in macroscopic scales only or should one call also short scale super-conductivity not giving rise to macroscopic super currents as super-conductivity. In other words: do the findings of Shen's team prove that the electrons above gap temperature do not form Cooper pairs or only that there are no macroscopic supra currents?

Whether the model works as such or not is not a life and death question for the TGD based model. One can quite well imagine that the first phase transition increasing hbar does not yet produce electron Compton lengths long enough to guarantee that the overlap criterion for the formation of Cooper pairs is satisfied. The second phase transition increasing hbar would do this and also scale up the lengths of magnetic flux tubes making possible the flow of supra currents as such even without reconnections. Also reconnections making possible the formation of very long flux tubes could be involved and would be made possible by the increase in the length of flux tubes.

For background see the chapter Super-Conductivity in Many-Sheeted Space-Time of "p-Adic Length Scale Hypothesis and Dark Matter Hierarchy" or the chapter Bio-Systems as Super-Conductors: Part I of "Quantum Hardware of Living Matter".

12 Comments:

At 8:21 AM, Blogger ThePeSla said...

Matti,

I do not think percolation is that profound a theory- but it is interesting. I agree it will make little difference for you concepts as it seems to me a matter of the right words for the right notion.

I am not sure I understand yet your breakthrough- as I said, certainly it must be a greater generalization. I do not think declaring something a new state of matter- although superconductivity is a great phenomenon to study, is more that a vague generalization to which certainly something deeper like how all the braids and twists work between dimensions would make things more definite.

If you get this comment I put it on my blog also in case. I do not have much deep to say today there, but it is probably an occupational hazard that those on the frontier like you and Kea, creatively and fundamentally, have come to expect breakthroughs.

ThePeSla

 
At 11:38 AM, Anonymous Matti Pitkanen said...

The best strategy is to develop in parallel general theory in top-to-bottom manner simultaneously with applications. High Tc super-conductivy represents second side of the coin. The best strategy to be lost in jungle of mathematical artefacts is to concentrate just to the mathematics as M-theorists have so convincingly demonstrated;-).


The mechanism of high Tc superconductivity has remained mystery for two decades although a lot is already known. New physics might be involved and high Tc super-conductivity is indeed excellent place for hierarchy of Planck constants to reveal itself. It is also extremely interesting from the point of view of TGD inspired quantum biology where phase transitions changing Planck constant and consequently flux tube lengths and reconnection are the basic mechanisms of bio-control.


Percolation phase transition is universal as one learns from Wikipedia article reconnection for magnetic flux tubes to longer ones as a percolation phase transitions would be a new application for the notion.

 
At 1:04 PM, Blogger kneemo said...

Back in 1989, Tate et al measured the Cooper pair mass in Niobium and found a value that disagrees with the standard theoretical prediction. The measured value was found to be higher than the predicted value, possibly indicating the presence of an extra field. Some authors have conjectured that the field is that of the graviphoton, and performed an analysis in an Einstein-Maxwell framework to describe the anomaly.

It is well known the Einstein-Maxwell equations arise in supergravity, where the graviphoton arises from compactification of M-theory on T^7 (seven torus). It may seem far fetched to invoke such abstract mathematics to explain Cooper pair anomalies, but in fact such an approach is increasingly becoming the norm, given that D-brane constructions are currently being studied to understand topological insulators.

 
At 9:20 PM, Anonymous Matti Pitkanen said...

I am not sure what you mean with graviphoton: additional spin 1 state of massive graviton or spin two boson coupling like photon?


I have discussed the anomaly in the chapter TGD and GRT of "Physics in Many-Sheeted Space-time". The TGD analogy of Einstein's equations with Maxwell's equations obtained at non-relativistic limit was used. The discussion could be probably simplified dramatically by thinking everything again in the recent conceptual framework.

a) The so called Thomson magnetic field in rotating superconductors is due to massivation of photons in superconductors: the field is proportional to the Compton length of massive photon and diverges for vanishing photon mass.

%%%%%%%
[Sidestep: An interesting question is whether the small mass of photons almost-predicted by TGD (photon eats the remaining Higgs component) actually corresponds to this mass depending on the physically determined IR cutoff.

Note also that the classical space-time correlate for the massivation of both photon and graviton and also of gluon is the finite transversal size of the "massless extremal" (topological light ray) carrying induced gauge fields propagating with maximal signal velocity in single direction and without dispersion.

Finite thickness of the topological light ray (tubular space-time sheet) would induce transversal mass although one has massless fields classically. In QCD similar transversal mass would be generated also for gluons. I realized this connection between Higgs mechanism and photon massivation just now.]
%%%%%


b) Thompson magnetic field gives a constant contribution to exponentially vanishing Meissner field and can be measured and is expressible solely in terms of electron mass and rotation frequency of super-conductor. The value of mass deduced was found to be somewhat larger than free electron mass although it should have been smaller: Delta m/m=about 10^(-4).

c) The proposal was that gravimagnetic field gives an additional contribution to the effective magnetic field. The contribution would be about 20 orders of magnitude larger than expected! A small breaking of Equivalence Principle is required and interpreted in terms of graviphoton massivation. TGD indeed almost-predicts a small mass for graviton. This is consistent with General Coordinate Invariance but I have not thought about the connection with Equivalence Principle.

d) The gravimagnetic field would affect Bohr quantization condition for rotating Cooper pair in external magnetic and gravimagnetic fields and imply that the actual magnetic field is stronger than its value deduced from the measurement. This would explain the anomaly qualitatively: the only problem is that the prediction is by a factor of about 1/23 too small and a really huge gravimagnetic field is needed.


This was what has been proposed by others. In TGD framework one can consider several alternative explanations.

a) Long ranged classical electroweak gauge fields are one possibility and classical Z^0 field could affect the effective value of electron mass measured from B.

b) Massive gravimagnetic field with large value of Planck constant is involved: gravimagnetic field is indeed proportional to the Compton length of massive graviton and therefore to hbar. Planck constant of order hbar=about 2^(66) is required to get strong enough gravimagnetic field and corresponds to the values appearing in TGD inspired model for living matter.

Compton length of graviton turns turns out to be of the order of solar system size. The mass of graviton would correspond for ordinary value of Planck constant to cell membrane thickness which appears also in TGD inspired model of bio-super-conductivity: as dark electron Compton length if I remember correctly. These scales appear also in the model of high Tc superconductivity.

The model might contain some truth in it but should be polished.

 
At 10:58 AM, Blogger kneemo said...

In N=2 SUGRA, the spin-2 graviton is associated with two spin 3/2 gravitinos and a spin-1 particle, the graviphoton, that couples to a central charge current (conserved mass current) with strength k=(8piG)^{1/2}. Unlike the photon, the graviphoton does not couple to the electric charge but rather to mass. Zachos and Scherk showed that the repulsive exchange of a spin-1 graviphoton between identical particles can exactly counteract the attractive exchange of a spin-2 graviton. Phenomenologically, the central charge to which the graviphoton couples is expected to be spontaneously generated by the breaking of GUT symmetry.

 
At 7:02 PM, Anonymous Matti Pitkanen said...

Thank you. This compensation between spin 2 and spin 1 is interesting: how generally it occurs? It would leave only scalar graviton perhaps identifiable in terms of gravitational potential. And what is the role of central charge?

TGD almost-predicts (it is better to not forget the "almost" since Higgs might be found and what do I say then?;-) that graviton, graviphoton, and graviscalar combine to single multiplet with small mass. All Higgses including their colored variants, their higher spin partners, as well as their superpartners would be eaten so that one would have just massive particles and their superpartners.
Also spin two analogs of gauge bosons are possible but should mediate forces with shorter range.

 
At 4:35 AM, Blogger Ulla said...

http://www.sciencedaily.com/releases/2011/03/110328101324.htm

 
At 2:00 AM, Blogger Ulla said...

http://physicsworld.com/cws/article/news/45558

 
At 9:37 AM, Blogger kneemo said...

Yes, there also exists a spin 0 graviscalar. For general N, there are N gravitinos in the multiplet. The central charge, on which the "fifth force" acts is at low energies expected to be carried by very heavy GUT particles such as the X and Y gauge bosons of the SU(5) models.

The modern view, is that these supergravity theories arise from compactifications of M-theory. For example, there exists an N=2 SUGRA in D=4 that makes use of two copies of CP^2, one for electric charges and the other for magnetic charges. Dyonic black holes in this theory carry these CP^2 charges, as well as extra graviphoton charges. There are many ways to recover these dyonic black hole solutions from configurations of M2 and M5 branes and other D=11 objects. However, such solutions can be mapped to each other via U-duality transformations. In the case of the two CP^2 dyonic black hole, the U-duality group is SU(3,3). If we instead use the split-octonions, we get two copies of the hyperbola H^{8,8} in N=8, D=4 SUGRA with U-duality group E7(7).

The E7(7) U-duality symmetry has proven to be extremely powerful, especially in the recent arguments for the all-loop UV-finiteness of N=8 SUGRA. See R. Kallosh's paper from earlier this month: arXiv:1103.4115 [hep-th].

 
At 1:39 PM, Blogger Ulla said...

http://arxiv.org/PS_cache/arxiv/pdf/1103/1103.3410v1.pdf
Spin-Momentum Locked Topological Surface States, non-trivial Berry’s phase and
magnetoelectric quantization in topological insulators

A new quantum phase of matter has been identified (bulk Topological-Insulator) whose surface is a new type of 2DEG (spin-momentum locked 1/2 Dirac gas).

 
At 2:58 AM, Blogger Ulla said...

http://www.sciencedaily.com/releases/2011/04/110405123245.htm

 
At 9:21 AM, Blogger Ulla said...

http://www.newscientist.com/article/mg21028073.800-how-to-turn-the-vacuum-into-a-superconductor.html

http://www.newscientist.com/article/mg21028071.400-catcher-in-the-sky-the-search-for-mystery-matter.html

 

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