Colloquium - Philip Phillips (UIUC) - Beyond BCS: An Exact Model for Superconductivity and Mottness

Philip Phillips (UIUC) 4/20/21 colloquium speaker
April 20, 2021
3:45PM - 4:45PM
Zoom webinar

Date Range
2021-04-20 15:45:00 2021-04-20 16:45:00 Colloquium - Philip Phillips (UIUC) - Beyond BCS: An Exact Model for Superconductivity and Mottness High-temperature superconductivity in the cuprates remains an unsolved problem because the cuprates start off their lives as Mott insulators in which no organizing principle such a Fermi surface can be invoked to treat  the electron interactions.  Consequently, it would be advantageous to solve even a toy model that exhibits both Mottness and superconductivity.  Part of the problem is that the basic model for a Mott insulator, namely the Hubbard model is unsolvable in any dimension we really care about.  To address this problem, I will start by focusing on the overlooked Z_2 emergent symmetry of a Fermi surface first noted by Anderson and Haldane. Noting that Mott insulators break this emergent symmetry, I show that the simplest model that suffices to describe Mottness is the Hatsugai-Kohmoto model. This model will then be solved exactly to reveal how superconductivity emerges in a doped Mott insulator, thereby forming a new paradigm for superconductivity in the copper-oxide superconductors.   [1] PWP, L. Yeo, E. Huang, Nature Physics, 16, 1175-1180 (2020).   Link to talk:  https://osu.app.box.com/file/802312755954?s=19c2upfsznooxm0jrlum1j11un00olfw   (Will need to copy link and paste to browser)         Zoom webinar America/New_York public

High-temperature superconductivity in the cuprates remains an unsolved problem because the cuprates start off their lives as Mott insulators in which no organizing principle such a Fermi surface can be invoked to treat  the electron interactions.  Consequently, it would be advantageous to solve even a toy model that exhibits both Mottness and superconductivity.  Part of the problem is that the basic model for a Mott insulator, namely the Hubbard model is unsolvable in any dimension we really care about.  To address this problem, I will start by focusing on the overlooked Z_2 emergent symmetry of a Fermi surface first noted by Anderson and Haldane. Noting that Mott insulators break this emergent symmetry, I show that the simplest model that suffices to describe Mottness is the Hatsugai-Kohmoto model. This model will then be solved exactly to reveal how superconductivity emerges in a doped Mott insulator, thereby forming a new paradigm for superconductivity in the copper-oxide superconductors.

 

[1] PWP, L. Yeo, E. Huang, Nature Physics, 16, 1175-1180 (2020).

 

Link to talk:  https://osu.app.box.com/file/802312755954?s=19c2upfsznooxm0jrlum1j11un00olfw

 

(Will need to copy link and paste to browser)