The extended diffusive Sachdev-Ye-Kitaev model as a sort of "strange metal"

Abstract

The 0+1-d Sachdev-Ye-Kitaev (SYK) fermionic model attracts nowadays a wide spread interest of the Condensed Matter community, as a benchmark toy model for strong electron correlation and non Fermi Liquid behavior. It is exactly solvable in the infrared limit and reproduces the linear dependence of the resistivity on temperature T, in linear response, typical of the strange metal phase of High Temperature Superconducting (HTS) materials. The breaking of its conformal symmetry requires ultraviolet corrections for a faithful description of its pseudo Goldstone Modes. Extension of the model to higher space dimension includes a local U(1) phase generating collective bosonic excitations driven by the additional ultraviolet contribution to the action. These excitations are studied here, in a temperature window of incoherent dynamics in which the expected chaotic regime has not yet taken over. We identify them as neutral diffusive energy excitations with temperature dependent lifetime h / k_B T. They provide thermalization of the system and contribute to the T dependence of the transport coefficients. The linear unbound T increase of particle current is confirmed by our hydrodynamic modelization. A quantum liquid in interaction with this system would become a Marginal Fermi Liquid.

16 pages,2 figures

References in corpus (7)

• Theory of the Nernst effect near quantum phase transitions in condensed matter, and in dyonic black holes
• Theory of universal incoherent metallic transport
• Higher Dimensional Generalizations of the SYK Model
• Diffusion in higher dimensional SYK model with complex fermions
• Superconducting instabilities in a spinful Sachdev-Ye-Kitaev model
• Superconducting critical temperature in the extended diffusive SYK model
• Thermal transport driven by charge imbalance in graphene in magnetic field, close to the charge neutrality point at low temperature: Non local resistance