Local Moment and Heavy Fermion Physics

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9312138 Coleman This proposal concerns heavy Fermion physics. Four projects will be considered: 1) Development of an odd frequency pairing model for heavy Fermion superconductivity. 2) A critical test for quadrupolar ground-state doublets in uranium heavy Fermion compounds. 3) Computation of the optical conductivity and dynamic susceptibility of Kondo insulators within an Anderson lattice model. 4) Development of a theory for anisotropic spin pairing to model the hidden itinerant order in URu2Si2. %%% This proposal is concerned with the behavior of electrons which behave, with regards to their transport in a material, as if they have large masses. This field has a rich history but recent discoveries have highlighted fundamental difficulties in our present understanding. For example, two newly discovered heavy Fermion materials - UPd2Al3 and UNi2Al3 - have large magnetic moments and exhibit superconductivity from the same magnetic degrees of freedom. This causes problems for the present theory of such materials. Also, recent anomalies observed in such properties as the specific heat in the heavy fermion material URu2Si2 suggest that there is a "hidden" variable in the theoretical description of the system. Work such as this is at the forefront of what is considered state-of-the-art in contemporary condensed matter theory. ***