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Terence Tao replied RE: Proof of the main conjecture in Vinogradov's mean value theorem for degrees higher than three (4 days ago)
+Timothy Gowers I've added the tag. I did try to post through the spnetwork system first, but the bookmark I had for it no longer worked. I see though now that the network web page is still up, so hopefully this post will get detected by it.

+Mark Lewko As Ben says, without the explicit dependence of constants on k one probably doesn't immediately get new bounds on zeta; for instance even the deep results of Wooley in recent years have not (to my knowledge) budged the classical Vinogradov-Korobov zerofree region on zeta, which is proven using the classical Vinogradov mean value theorem. But perhaps some variant of the methods can say something new. Recently for instance Bourgain used the decoupling theorem to slightly improve the upper bound on zeta on the critical line (making a little bit of progress towards the Lindelof hypothesis). Naively one could perhaps hope to somehow combine the decoupling methods with the efficient congruencing methods to prove some super-theorem that could have further applications, though currently the methods look very incompatible (the latter relies very much on the arithmetic structure, while the former heavily relies on generalising to the non-arithmetic setting for induction purposes).
Ben Green replied RE: Proof of the main conjecture in Vinogradov's mean value theorem for degrees higher than three (4 days ago)
They defer to Wooley's paper for a discussion of the implications for zeta, which would have to do with the zero-free region if I understand correctly. My vague impression, not having looked at the matter in any detail, is that explicit implied constants will be required in the estimates - or at least some indication of the form of the dependence of these constants on k, s and eps. From what I saw from a glance through the preprint this morning, that might be a slightly tricky undertaking.
Mark Lewko replied RE: Proof of the main conjecture in Vinogradov's mean value theorem for degrees higher than three (4 days ago)
This is certainly a spectacular breakthrough. I'm curious what the implications to zeta are? 
Holden Lee commented on Ramanujan Coverings of Graphs (4 days ago)
Notes on Doron Puder's talk "Ramanujan coverings of graphs" at IAS/CSDM seminar today: S6 in https://dl.dropboxusercontent.com/u/27883775/wiki/math/pdfs/csdm.pdf #spnetwork arXiv:1506.02335
Timothy Gowers replied RE: Proof of the main conjecture in Vinogradov's mean value theorem for degrees higher than three (4 days ago)
This sounds amazing, and perhaps worth an #spnetwork  tag, unless that idea has basically died.
Richard Elwes replied RE: Proof of the main conjecture in Vinogradov's mean value theorem for degrees higher than three (5 days ago)
Should it read "they have their most spectacular result yet"?
Terence Tao commented on Proof of the main conjecture in Vinogradov's mean value theorem for degrees higher than three (5 days ago)
In the last few years, Bourgain and Demeter have been pursuing various applications of their decoupling theorem in restriction theory, which allows for the accurate estimation of various exponential integrals or exponential sums. In a paper appearing today on the arXiv with Guth, they have their most spectacular conjecture application yet - settling in full generality the main conjecture of Vinogradov on mean values of exponential sums. There has been much recent work on this by Wooley and his coauthors using the "efficient congruencing" method, but the methods of Bourgain-Demeter-Guth look to be quite different. There should be applications of this result to Waring's problem and to upper bound on the Riemann zeta function. Anyway, certainly a paper I intend to read through in the coming weeks... #spnetwork arXiv:1512.01565
#ice new topic created (Nov. 12, 2015)
David Washington replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 12, 2015)
That's just beautiful, thank you, so many thoughts here :)
John Baez replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 11, 2015)
+Virginia Benedict - the crystal structure of snowflakes is usually the same: hexagonal ice, called ice Ih.  But as the snowflakes move up and down through clouds and encounter different temperatures and humidities, they grow in different ways. 

You might like my posts on the classification of snowflakes:

https://plus.google.com/u/0/117663015413546257905/posts/cuM8xMk5zDS

how different conditions produce different kinds of snowflakes:

https://plus.google.com/u/0/117663015413546257905/posts/FUytP1QY2me

and the mystery of triangular snowflakes:

https://plus.google.com/u/0/117663015413546257905/posts/VCAJF5WhupF
Virginia Benedict replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 11, 2015)
Thank you  +John Baez  I was not aware. However, come to think of it not two snowflakes are alike... wonder if it is relevant here in this context.
Andrew Robertson replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 11, 2015)
"would it be possible to use the free electrons"

In this case, the electrons are not free, they're bound to the oxygen as anions. But the suggestion appears to be that you could get electrical current from proton flow instead.

"we could remove a significant amount of energy to make the transition points from structure type to structure type too large to change states"

Phase changes are state functions, in other words you will always get a particular phase for a particular combination of temperature and pressure. It takes time to change phases but the energy barriers that regulate that transition time are a direct function of the chemistry of the molecules so I don't think there's much (or any) engineering we could do there.
Michael Van Meter replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 11, 2015)
+Andrew Robertson​ so would it be possible to use the free electrons in configuration as an electrical source via diode pump? And if so do you think we could remove a significant amount of energy to make the transition points from structure type to structure type too large to change states for the entire structure at once? Maybe cause surface sublimation from ambient energy but the core to be low enough energy to prevent rapid decomposition.
Andrew Robertson replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 11, 2015)
This superionic ice looks like a metal but in reverse, i.e. with mobile protons in a crystalline lattice of anions.
Andrew Robertson replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 11, 2015)
I suspect the transition would be quite fast +Brian Fitzgerald. With normal forms of ice transition, the molecules have to reorient themselves from one low-energy configuration to another via unfavourable high energy configurations (like climbing a mountain pass to get from one valley to another). If these  energy barriers are high enough, the transition can take a long time.

In this case, however, the protons are mobile enough to fit into any new configuration without much trouble so I suspect the superionic ice will disappear as soon as the pressure is released. The crystal will likely get trapped in many exotic forms before finally returning to the hexagonal crystal we all know and love though.
John Baez replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 10, 2015)
+Brian Fitzgerald - Fun question!  I don't know how long various forms of ice would last at ordinary pressure before reverting to ordinary ice or water.  The superionic ices mentioned here would probably be among the least stable, since they're only happy when the pressure exceeds 500,000 atmospheres.  Here are some better candidates:

"If cooled very rapidly liquid water forms a glass, for example, hyperquenched glassy water (HGW). HGW is formed by the rapid spraying of a fine jet of micron-sized water droplets into very cold liquefied gas (for example, propane), or onto a very cold solid substrate, about or below 80 K or by cooling capillary tubes containing bulk liquid water (~100 micron diameter) with liquid helium at 4.2 K. These methods all involve cooling rates of greater than 10,000 degrees Celsius per second. These glasses have some structural and thermodynamic similarity with liquid water at 273 K, due to their methods of formation and amorphous properties. A similar material is amorphous solid water (ASW), formed from the slow deposition of water vapor, at less than 2 nanometers per second, on a very cold metal crystal surface below 120 K.  ASW (also called low density glass, 0.94 grams per cubic centimeter) may contain considerable voids and dangling hydrogen bonds, which are removed by annealing under vacuum at 120-140 K when the glass converts to material indistinguishable from HGW or low density amorphous ice (LDA, 0.94 grams per cubic centimeter) at slightly higher temperatures."

Once formed, I imagine these might take a while to revert to ordinary ice.  Another interesting candidate for a long-lived alternate form of ice is ice Ic, the cubic form of ice I.

The quote above is paraphrased from Martin Chaplin's website, which is the best website on ice:

http://www1.lsbu.ac.uk/water/amorphous_ice.html
John Baez replied RE: Superionic to superionic phase change in water: consequences for the interiors of Uranus and Neptune (Nov. 10, 2015)
+David Tweed - that was a deliberate "pun".  I was imagining ice giants from Norse mythology, but I haven't found anything about those.   According to the Runescape Wiki:

Ice giants are a type of giant often found in icy areas. They have a relatively high Constitution level and hit a maximum of 185 life points. They are the highest level giants in free to play. Ice giants always drop big bones and tend to be weak against fire spells (magic) and crush attacks. Ice giants are not aggressive to players of combat level 103 and higher. Many players seek these monsters for experience and charms. Ice giants were the third monster to ever hold the title of Strongest Monster in RuneScape.