Local Quantum Criticality and Emergent Phases

Qimiao Si

Rice University


   I will summarize the theoretical aspects of local quantum criticality, and the experimental evidence from anomalous dynamical scaling, collapsing energy scale of Kondo breakdown and Fermi surface jump in heavy fermion systems.


    I will also discuss the theoretical reasoning for the emergence of novel magnetic phases and the corresponding global phase diagram, and attempt to place various quantum-critical heavy fermion compounds in this global phase diagram.


    Finally, I will outline several promising directions to explore in the future: the role of Berry phase in the global phase diagram [1]; the possibility of local quantum criticality in mixed-valence settings [2]; and the interplay among electron localization (in the form of Kondo breakdown here), magnetism and unconventional superconductivity, both in the context of existing experiments [3,4] and as a general theoretical issue.


[1] P. Goswami and Q. Si, Phys. Rev. Lett. 107, 126404 (2011).

[2] J. H. Pixley, S. Kirchner, K. Ingersent, and Q. Si, arXiv:1108.5227.

[3] T. Park et al., J. Phys.: Condens. Matter 23, 094218 (2011);

      H. Shishido  et al., J. Phys. Soc. Jpn. 74, 1103 (2005).

[4] O. Stockert et al., Nature Phys. 7, 119 (2011).

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