Nature of Hidden Order in URu2Si2

          @misc{ scivideos_PIRSA:08040032,
            doi = {10.48660/08040032},
            url = {https://pirsa.org/08040032},
            author = {Luke, Graeme},
            keywords = {},
            language = {en},
            title = {Nature of Hidden Order in URu2Si2},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2008},
            month = {apr},
            note = {PIRSA:08040032 see, \url{https://scivideos.org/pirsa/08040032}}
          }
          

Abstract

URu2Si2 is a moderate heavy fermion system which undergoes two transitions with decreasing temperature. The lower transition (1.5K) is to a possibly unconventional superconducting state, whereas the nature of the upper transition (17.5K) is poorly understood. Large lambda-like anomalies are seen in specific heat, along with strong signatures in other transport measurements such as resistivity and magnetic susceptibility. Neutron diffraction measurements only detect a very small ordered moment (0.03 μB), which is too small to give such large bulk signatures. This has prompted theorists to propose various exotic mechanisms to explain this so-called hidden order. I will review our group\'s efforts to understand this system, including our results on non-linear susceptibility and muon spin relaxation under hydrostatic pressure, as well as inelastic neutron scattering studies of this system.