PIRSA:16110035

Non-perturbative emergence of non-Fermi liquid behaviour in d=2 quantum critical metals

APA

Saterskog, P. (2016). Non-perturbative emergence of non-Fermi liquid behaviour in d=2 quantum critical metals. Perimeter Institute for Theoretical Physics. https://pirsa.org/16110035

MLA

Saterskog, Petter. Non-perturbative emergence of non-Fermi liquid behaviour in d=2 quantum critical metals. Perimeter Institute for Theoretical Physics, Nov. 04, 2016, https://pirsa.org/16110035

BibTex

          @misc{ scivideos_PIRSA:16110035,
            doi = {10.48660/16110035},
            url = {https://pirsa.org/16110035},
            author = {Saterskog, Petter},
            keywords = {Quantum Matter},
            language = {en},
            title = {Non-perturbative emergence of non-Fermi liquid behaviour in d=2 quantum critical metals},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2016},
            month = {nov},
            note = {PIRSA:16110035 see, \url{https://scivideos.org/pirsa/16110035}}
          }
          

Petter Saterskog Leiden University

Talk numberPIRSA:16110035
Source RepositoryPIRSA
Collection

Abstract

We consider d=2 fermions at finite density coupled to a critical boson. In the quenched or Bloch-Nordsieck approximation, where one takes the limit of fermion flavors N_f→0, the fermion spectral function can be determined {exactly}. We show that one can obtain this non-perturbative answer thanks to a specific identity of fermionic two-point functions in the planar local patch approximation. The resulting spectrum is that of a non-Fermi liquid: quasiparticles are not part of the exact fermionic excitation spectrum of the theory. Instead one finds continuous spectral weight with power law scaling excitations. Moreover, at low energies there are three such excitations at three different Fermi surfaces, two with a low energy Green's function G∼(ω−v k)^−1/2 and one with G∼|ω+k|^−1/3. We proceed to study this model with a finite N_f but still neglecting fermionic loops with 3 or more vertices, motivated by multiloop cancellations at large k_F. We still find a non-Fermi liquid but with a different IR spectrum.