tag:blogger.com,1999:blog-7307840825023135484.post1761430029122403448..comments2012-02-07T15:48:38.662+13:00Comments on Arcadian Pseudofunctor: Compulsory Graphene PostKeahttp://www.blogger.com/profile/05652514294703722285noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-7307840825023135484.post-10468396884084083992010-11-05T09:47:22.725+13:002010-11-05T09:47:22.725+13:00Great, kneemo! Nice to hear from you.Great, kneemo! Nice to hear from you.Keahttps://www.blogger.com/profile/05652514294703722285noreply@blogger.comtag:blogger.com,1999:blog-7307840825023135484.post-77766037903357757642010-11-05T04:50:31.358+13:002010-11-05T04:50:31.358+13:00The real fun starts with topological insulators. ...The real fun starts with topological insulators. Think of this as the case when the number of dirac cones is odd, leading to topologically protected metallic boundary states. Take a look at the slides by S. Ryu: <a href="http://mitchell.physics.tamu.edu/Conference/AdS-CFT/documents/S_Ryu.pdf" rel="nofollow">Topological Insulators/Superconductors and D-branes</a>.<br /><br />Kitaev classified many of the topological insulators and superconductors by their homotopy groups using Bott periodicity (<a href="http://arxiv.org/abs/0901.2686" rel="nofollow">arXiv:0901.2686</a>). Essentially, each system he considers has a corresponding non-linear sigma model, with a given target space given by a coset G/H. By computing the homotopy groups (pi_n(G/H)) for each coset (for a given n), one can determine if there exists a topological insulator or superconductor in a given dimension. The vanishing of the nth homotopy group means there is no topological insulator or superconductor present in the corresponding dimension.<br /><br />The relation to supergravity is pretty straightforward mathematically, as a given supergravity theory can be viewed a non-linear sigma model with scalar fields taking values in a target space G/H, where G is the nonlinear bosonic symmetry and H (R-symmetry group) is a maximal compact subgroup of G. Relating a given supergravity theory to a condensed matter system amounts to matching up their non-linear sigma models and target spaces. This gives provides a theoretical 'bridge' between the two subjects, allowing one to re-cast the condensed matter system in the language of AdS/CFT and D-branes for instance.kneemohttps://www.blogger.com/profile/08396427736998362077noreply@blogger.comtag:blogger.com,1999:blog-7307840825023135484.post-63531025864016383302010-11-05T00:57:14.468+13:002010-11-05T00:57:14.468+13:00From your link: All charges comes from dissipation...From your link: All charges comes from dissipation, entropy. Like a quantized entropy? <br />The strong force vanish first at high temperatures?<br /><br />What about your graphene link that showed the graphene was ruled only by alpha and pi, nothing at all from the graphene. It is totally from the vacuum field alone? Reminds me of induced metabolism in life.Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.comtag:blogger.com,1999:blog-7307840825023135484.post-31325130763201739742010-11-04T19:49:20.934+13:002010-11-04T19:49:20.934+13:00Ah, so I am not the first to notice this link to &...Ah, so I am <a href="http://users.ictp.it/~markusm/Talks/Trento10.pdf" rel="nofollow">not the first</a> to notice this link to 'AdS/CFT' results for quark gluon plasmas etc. Unfortunately, my colleagues here are not thinking about these things ...Keahttps://www.blogger.com/profile/05652514294703722285noreply@blogger.com