PIRSA:17020091

Superconductivity near a quantum-critical point --- the special role of the first Matsubara frequency

Chubukov, A. (2017). Superconductivity near a quantum-critical point --- the special role of the first Matsubara frequency. Perimeter Institute. https://pirsa.org/17020091

Chubukov, Andrey. Superconductivity near a quantum-critical point --- the special role of the first Matsubara frequency. Perimeter Institute, Feb. 14, 2017, https://pirsa.org/17020091 

          @misc{ pirsa_PIRSA:17020091,
            doi = {10.48660/17020091},
            url = {https://pirsa.org/17020091},
            author = {Chubukov, Andrey},
            keywords = {Condensed Matter},
            language = {en},
            title = {Superconductivity near a quantum-critical point --- the special role of the first Matsubara frequency},
            publisher = {Perimeter Institute},
            year = {2017},
            month = {feb},
            note = {PIRSA:17020091 see, \url{https://pirsa.org}}
          }

Andrey Chubukov

University of Minnesota

Talk number
PIRSA:17020091
Collection
Talk Type
Subject
Abstract

Near a quantum-critical point in a metal strong fermion-fermion interaction mediated by a soft collective boson gives rise to incoherent, non-Fermi liquid behavior. It also often gives rise to superconductivity which masks the non-Fermi liquid behavior. We analyze the interplay between the tendency to pairing and fermionic incoherence for a set of quantum-critical models with effective dynamical interaction between low-energy fermions. We argue that superconducting Tc is non-zero even for strong incoherence and/or weak interaction due to the fact that the self-energy from dynamic critical fluctuations vanishes for the two lowest fermionic Matsubara frequencies $\omega_m = \pm \pi T$. We obtain the analytic formula for T_c which reproduces well earlier numerical results, including the ones  for the  electron-phonon model at vanishing Debye frequency.