High Temperature Superconductivity

Many years ago in visits to Santa Barbara, I consulted Prof. Douglas Scalapino about a change of course. From High Energy Theoretical Physics to Condensed Matter Theory. He wisely told me that if I did that I should follow the phenomenological work on the field; the experimental situation is not clear, he said; it is likely that the lack of purity of samples is obscuring the physical behavior. The theory problem I was interested in was High Temperature Superconductivity (HTSC).

I remember him talking to Bob Sugar about the Dirac dispersion relation being relevant for this and other problems. All was mysterious for me.

Now turn twenty five years ahead. I am reading Zaanen et al. from Leiden, where the initial phenomenon was discovered by Onnes almost a hundred years ago.

This is as interesting as it can be.

During the same number of years another development has gone its own happy way independently from HTSC. After so many years of "useless" work, Zaanen et al. tell us that they found a way to connect these two branches of mathematical methods of physics. Through the so called, AdS/CFT connection they were able to solve the "sign" problem for fermions and obtained the long sought dispersion relation, sure enough along the lines that Doug Scalapino thought it was going to come from. A dispersion relation where the energy and momentum are proportional for electrons, as if they were massless.

To add more interest to my story, I should add that John Cardy was around. He became a world leader in the emergent field of Conformal Field Theory (CFT), he is now a full time professor near his alma mater. He studied at Cambridge University, and now he is tenured at Oxford.

If I were able to read the future, I should've taken the whole bunch, to Borsodis, a watering hole near campus; and work hard until we got the thing down.

Life does not work like that though. Many smart people worked on String Theory, Mathematics, Conformal Field Theory, High Temperature Sueprconductivity, and now maybe, just maybe, we may have a solution faintly coming out.

So it goes.