Tuesday, October 19, 2010

String Theory Tackles Strange Metal

Forget about high energy physics or elementary particles. The testing grounds for String Theory is condensed matter physics!


As if you are not convinced already by all the possibilities presented with the topological insulator, we now have even more ideas that various aspects of String Theory can be analogously tested in condensed matter. I mentioned a paper a while back that suggested that an aspect of String theory might explain the phenomenon of high-Tc superconductors (among other things). Well now, a new paper just published in PRL[1] extended that work and used it to come up with a model to describe the strange metal state of these cuprate high-Tc superconductors.

In 2003, condensed matter physicist Subir Sachdev of Harvard University, in Cambridge, Massachusetts, and his colleagues, put forward a new model called fractionalized Fermi liquid (FFL) that seemed to account for some of the properties of strange metals, including the variation of their resistance with temperature1. Unlike in the standard Fermi liquid model, the quantum mechanical spins of some electrons in the material are linked together in an FFL.

Now, in a paper published in Physical Review Letters2 on 4 October, Sachdev shows that the FFL model's characteristics match those of a type of black hole in string theory. "We're still a long way from saying string theory explains strange matter but we have hope," Sachdev says. "It's very exciting because it's a whole new perspective." He adds that he's been learning string theory at a breakneck speed.

We'll have to see how far this can be taken.

[1] S. Sachdev et al., Phys. Rev. Lett. v.105, p.151602 (2010).

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