- Broida 1640
Refreshments served at 3:40!
Chandra Varma - UC Riverside
Spurred by some strange experimental observations in some superconductors, the theory
of a new collective mode in superconductors and how it can be experimentally found very
easily under certain circumstances was provided in 1981. It was called the "Amplitude
Mode" to distinguish it from the "Phase Modes" which provide Josephson eects and
which in homogeneous superconductors are coupled to charge density
uctuations and are at the energies of the plasmons. More generally, this mode is the amplitude mode of a
particle-hole symmetric U(1) eld, i.e the model treated by Higgs and others in the1960's
whose generalizations have played an important role in the standard model of particle
physics. Recently the amplitude or Higgs mode for d-wave superconductors have also been
discussed, where its various cousins may also be found.
I will tell the story of the above and why such modes were missed in the theory of
superconductivity for so long and the applications of the ideas about such modes for cold
bosons and fermions in optical lattices. I will also comment, as a very interested outsider
and an enthusiast, on the Higgs in particle physics being discovered at LHC from the point
of view of the theory of superconductivity.