Heavy fermion physics - perspectives from look alikes

Andy Schofield

University of Birmingham, UK


    Among the many intriguing features of heavy fermion metals is the observation that the small energy scales intrinsic to these materials often allow them to be tuned to quantum critical points. Heavy fermion quantum criticality has been been extensively studied and shown, in many cases, to be at odds with the theoretical expectations of the Landau-Ginsburg-Hertz-Millis type action. The failures of that theoretical approach have now also been much studied and we are faced with an embarrassment of new data and few theoretical tools to tackle them.

    In this talk I will draw together the physics of other itinerant quantum critical systems to provide a phenomenological comparison between the heavy fermion quantum criticality and that manifest in other metals. Some of these are look alike systems such as layers of helium where localized atoms play the role of Kondo moments, while in the oxide metals the complexity of Kondo physics is absent. I will also summarise one theoretical approach to the Kondo lattice problem that involves frustrating out the Kondo coupling as a control parameter for the theory.

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