University of Birmingham > Talks@bham > Theoretical Physics Journal Club and Group Meeting > A Rigorous Demonstration of Superconductivity in a Repulsive Hubbard Model

A Rigorous Demonstration of Superconductivity in a Repulsive Hubbard Model

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  • UserManjinder Kainth - University of Birmingham
  • ClockFriday 26 April 2019, 13:00-14:00
  • HouseTheory Library.

If you have a question about this talk, please contact Manjinder Kainth.

We have rigorously shown that a strong Hubbard repulsion can cause superconductivity. The model, which has a particular set of local symmetries, manifests the phase diagram of many unconventional superconductors; anti-ferromagnetism paramagnetism, superconductivity, and even ferromagnetism are all observed. The key technique in the analysis is an exact non-linear fermion transformation, which preserves the correlated motion of electrons while removing the strong interactions. Using resolvent formalism, it is exactly shown that two holes at the Mott point bind to form a localised Cooper pair. As interactions are now weak, we then use BCS mean field theory to calculate the energy, excess pairing, and superconducting gap. These results are compared to exact diagonalisation of finite sized systems and show good agreement. At the Mott point the system is an anti-ferromagnet, and a superconducting phase quickly appears upon doping, and then vanishes.

This talk is part of the Theoretical Physics Journal Club and Group Meeting series.

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