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Aparently very interesting, will it survive the short hype? Relevant work describing mirror charges of topological insulators and the classical boundary conditions were done by Ismo and Ari. But the two communities don't know each other and so they are never cited. Also a way to produce new things...

Thanks for noticing! Indeed, I had no idea that Ari (don't know Ismo) was involved in the field. Was it before Kane's proposal or more recently? What I mostly like is that semiconductors are good candidates for 3D TI, however I got lost in the quantum field jargon. Yesterday, I got a headache trying to follow the Majorana fermions, the merons, skyrnions, axions, and so on. Luzi, are all these things familiar to you?

Ismo Lindell described in the early 90's the mirror charge of what is now called topological insulator. He says that similar results were obtained already at the beginning of the 20th century... Ismo Lindell and Ari Sihvola in the recent years discussed engineering aspects of PEMCs (perfect electro-megnetic conductors,) which are more or less classical analogues of topological insulators. Fundamental aspects of PEMCs are well knwon in high-energy physics for a long time, recent works are mainly due to Friedrich Hehl and Yuri Obukhov. All these works are purely classical, so there is no charge quantisation, no considerations of electron spin etc. About Majorana fermions: yes, I spent several years of research on that topic. Axions: a topological state, of course, trivial :-) Also merons and skyrnions are topological states, but I'm less familiar with them.

"Non-Abelian systems1, 2 contain composite particles that are neither fermions nor bosons and have a quantum statistics that is far richer than that offered by the fermion-boson dichotomy. The presence of such quasiparticles manifests itself in two remarkable ways. First, it leads to a degeneracy of the ground state that is not based on simple symmetry considerations and is robust against perturbations and interactions with the environment. Second, an interchange of two quasiparticles does not merely multiply the wavefunction by a sign, as is the case for fermions and bosons. Rather, it takes the system from one ground state to another. If a series of interchanges is made, the final state of the system will depend on the order in which these interchanges are being carried out, in sharp contrast to what happens when similar operations are performed on identical fermions or bosons." wow, this paper by Stern reads really weired ... any of you ever looked into this?

C'mon Leopold, it's as trivial as the topological states, AKA axions! Regarding the question, not me!

just looked up the wikipedia entry on axions .... at least they have some creativity in names giving: "In supersymmetric theories the axion has both a scalar and a fermionic superpartner. The fermionic superpartner of the axion is called the axino, the scalar superpartner is called the saxion. In some models, the saxion is the dilaton. They are all bundled up in a chiral superfield. The axino has been predicted to be the lightest supersymmetric particle in such a model.[24] In part due to this property, it is considered a candidate for the composition of dark matter.[25]"

Thank's Leopold. Sorry Luzi for being ironic concerning the triviality of the axions. Now, Leo confirmed me that indeed is a trivial matter. I have problems with models where EVERYTHING is involved.

Well, that's the theory of everything, isn't it?? Seriously: I don't think that theoretically there is a lot of new stuff here. Topological aspects of (non-Abelian) theories became extremely popular in the context of string theory. The reason is very simple: topological theories are much simpler than "normal" and since string theory anyway is far too complicated to be solved, people just consider purely topological theories, then claiming that this has something to do with the real world, which of course is plainly wrong. So what I think is new about these topological insulators are the claims that one can actually fabricate a material which more or less accurately mimics a topological theory and that these materials are of practical use. Still, they are a little bit the poor man's version of the topological theories fundamental physicists like to look at since electrdynamics is an Abelian theory.

I have the feeling, not the knowledge, that you are right. However, I think that the implications of this light quantum field effects are great. The fact of being able to sustain two currents polarized in spin is a technological breakthrough.

not sure how much I can contribute to your apparently educated debate here but if I remember well from my work for the master, these non-Abelian theories were all but "simple" as Luzi puts it ... and from a different perspective: to me the whole thing of being able to describe such non-Abelian systems nicely indicates that they should in one way or another also have some appearance in Nature (would be very surprised if not) - though this is of course no argument that makes string theory any better or closer to what Luzi called reality ....

Well, electrodynamics remains an Abelian theory. From the theoretical point of view this is less interesting than non-Abelian ones, since in 4D the fibre bundle of a U(1) theory is trivial (great buzz words, eh!) But in topological insulators the point of view is slightly different since one always has the insulator (topological theory), its surrounding (propagating theory) and most importantly the interface between the two. This is a new situation that people from field and string theory were not really interested in.

guys... how would you explain this to your gran mothers?

as a start of a peer reviewed paper this is an interesting first paragraph: "I recently saw an old friend for the first time in many years. We had been Ph.D. students at the same time, both studying science, although in different areas. She later dropped out of graduate school, went to Harvard Law School and is now a senior lawyer for a major environmental organization. At some point, the conversation turned to why she had left graduate school. To my utter astonishment, she said it was because it made her feel stupid. After a couple of years of feeling stupid every day, she was ready to do something else."

Hilarious! Mr Schwartz, who made a PhD at Stanford(!) and apparently is working as a postdoc now, has finally discovered what science is about!!! Quote: "That's when it hit me: nobody did. That's why it was a research problem." And he seems so excited about it! I think he should not only get published in 6.14 journal, but also get the Nobel Prize immediately! Seriously, after reading something like this, how one may not have superstitions about the educational system in the US?

Not sure by what you mean by source localisation, but this using gzip to discern "biological" from "non-biological" images seems to me *very* tricky... I mean, there's a lot of other factors that may affect compressibility of an image than just mere "regularity" of the pattern, and if they haven't controlled for these, this is just bullsh1t... (For instance did they use the same imaging device to take those images? What about lighting conditions and exposure? etc). The apostle of sometimes surprising uses of compression is prof. Shmidhuber from IDSIA...

I completely agree with you..... still if you have one instrument on board the spacecraft and your picture compressibility is a noisy indicator of some interesting source .... we could try to perform some probabilistic reasoning

I think they (IDSIA-Schmidhuber) are planning on putting something about that also inside the Acta Futura paper...

nice ....

I'm a little bit surprised as well about the crude story of the burglar, pure nonsense, of course! But the paper is deadly serious, Alberto and Paul are my best collaborators in metamaterials and optics, they are not this type of TV-show scientists as Leonhardt etc. But as Alberto told me: just put the name "cloak" in the title and you're in all the news. It's not science, it's kindergarden :-(.

well sure competitiveness is good but to verify (and that should be the case for scientific experiments) the code should be public, it would be nice to have something like bibtex for code libraries or versions used.... :) btw I fully agree that the code should go public, I had lots of trouble reproducing (reprogramming) some papers in the past ... grr