Thermoelectric transport in disordered metals without quasiparticles: The Sachdev-Ye-Kitaev models and holography

• DOI: 10.1103/physrevb.95.155131
• Publication Date: 2017-04-18T22:08:46Z
• Authors: Richard A. Davison; Wenbo Fu; Antoine Georges; Yingfei Gu; Kristan Jensen; Subir Sachdev
• Keywords: velocity; metal; fluctuation; [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th]; chaos; 500; finite temperature; 530; 7. Clean energy; black brane; fermion number; [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph]; thermal; thermodynamics; quasiparticle: excited state; effective action; temperature: low; momentum: conservation law; thermodynamical; transport theory; anti-de Sitter; holography; higher-dimensional; entropy; fermion: model

We compute the thermodynamic properties of Sachdev-Ye-Kitaev (SYK) models fermions with a conserved fermion number, $\mathcal{Q}$. extend previously proposed Schwarzian effective action to include phase field, and this describes low temperature energy $\mathcal{Q}$ fluctuations. obtain higher-dimensional generalizations SYK which display disordered metallic states without quasiparticle excitations, we deduce their thermoelectric transport coefficients. also examine corresponding Einstein-Maxwell-scalar theories on black brane geometries interpolate from either AdS$_4$ or AdS$_5$ an AdS$_2\times \mathbb{R}^2$ \mathbb{R}^3$ near-horizon geometry. These provide holographic descriptions non-quasiparticle momentum conservation. find precise match between thermodynamics models. In both Seebeck coefficient is exactly equal $\mathcal{Q}$-derivative entropy. For models, quantum chaos, as characterized by butterfly velocity Lyapunov rate, universally determines thermal diffusivity, but not charge diffusivity.