The square lattice Hubbard model within cluster dynamical mean-field theory
COMP Seminar. Speaker: Tuomas Vanhala (Doctoral candidate in QD and QMP).
The square lattice Hubbard model within cluster dynamical mean-field theory: Interplay of magnetism and superconductivity
The cluster dynamical mean-field theory (cluster DMFT)  is a family of numerical methods which combine the exact solution of a small luster problem with a mean-field treatment of the lattice physics. Thus local correlation effects that take place within the small reference system are taken into account in an unbiased way. This allows one to study physical phenomena, such as Mott insulator transitions or fermionic superfluidity resulting from repulsive interactions, which are not readily described by simpler mean-field approaches.In this talk I will discuss the phase diagram of the repulsively interacting square-lattice Hubbard model from the perspective of DMFT methods. This model is thought to be relevant to high-Tc cuprate superconductors  and can also be studied in ultracold gas experiments . I will first describe the DMFT method using the effective medium interpretation of the DMFT equations. I will then briefly review the most interesting cluster DMFT results about d-wave superconductivity in the Hubbard model, discussing critical temperatures and the superconducting "dome" [4,5]. Finally, I will present results from our study of the interplay of superconductivity and non-uniform, or striped, magnetism in the ground state of the model .
The talk will be followed by a coffee in COMP's kitchen, Y-wing, 4th floor. All are welcomed!
 T. A. Maier et al., Rev. Mod. Phys. 77, 1027
 P. A. Lee et al., Rev. Mod. Phys. 78, 17
 A. Mazurenko et al., Nature 545, 462
 T. A. Maier et al., Phys. Rev. Lett. 95, 237001
 L. Fratino et al., Scientific Reports 6, 22715
 T. Vanhala and P. Törmä, arXiv:1708.06749