TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.13.3.073
TI  - High-frequency transport and zero-sound in an array of SYK quantum dots
PY  - 2022/09/29
UR  - https://www.scipost.org/SciPostPhys.13.3.073
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 13
IS  - 3
SP  - 073
A1  - Aleksey, Lunkin
AU  - Feigel'man, Mikhail V.
AB  - We study an array of strongly correlated quantum dots of complex SYK type and account for the effects of quadratic terms added to the SYK Hamiltonian; both local terms and inter-dot tunneling are considered in the non-Fermi-liquid temperature range $T \gg T_{FL}$. We take into account soft-mode fluctuations and demonstrate their relevance for physical observables. Electric $\sigma(\omega,p)$ and thermal $\kappa(\omega,p)$ conductivities are calculated as functions of frequency and momentum for arbitrary values of the particle-hole asymmetry parameter $\mathcal{E}$. At low-frequencies $\omega \ll T$ we find the Lorenz ratio $L = \kappa(0,0)/T\sigma(0,0)$ to be non-universal and temperature-dependent. At $\omega \gg T$ the conductivity $\sigma(\omega,p)$ contains a pole with nearly linear dispersion $\omega \approx sp\sqrt{\ln\frac{\omega}{T}}$ reminiscent of the "zero-sound", known for Fermi-liquids. We demonstrate also that the developed approach makes it possible to understand the origin of heavy Fermi liquids with anomalously large Kadowaki-Woods ratio.
ER  -

@Article{10.21468/SciPostPhys.13.3.073,
	title={{High-frequency transport and zero-sound in an array of SYK quantum dots}},
	author={Aleksey. V. Lunkin and  Mikhail . V. Feigel'man},
	journal={SciPost Phys.},
	volume={13},
	pages={073},
	year={2022},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.13.3.073},
	url={https://scipost.org/10.21468/SciPostPhys.13.3.073},
}