Higher-dimensional Sachdev-Ye-Kitaev non-Fermi liquids at Lifshitz transitions

Haldar, Arijit and Banerjee, Sumilan and Shenoy, Vijay B (2018) Higher-dimensional Sachdev-Ye-Kitaev non-Fermi liquids at Lifshitz transitions. In: PHYSICAL REVIEW B, 97 (24).

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Abstract

We address the key open problem of a higher-dimensional generalization of the Sachdev-Ye-Kitaev (SYK) model. We construct a model on a lattice of SYK dots with nonrandom intersite hopping. The crucial feature of the resulting band dispersion is the presence of a Lifshitz point where two bands touch with a tunable power-law divergent density of states (DOS). For a certain regime of the power-law exponent, we obtain a class of interaction-dominated non-Fermi-liquid (NFL) states, which exhibits exciting features such as a zero-temperature scaling symmetry, an emergent (approximate) time reparameterization invariance, a power-law entropy-temperature relationship, and a fermion dimension that depends continuously on the DOS exponent. Notably, we further demonstrate that these NFL states are fast scramblers with a Lyapunov exponent lambda(L) proportional to T, although they do not saturate the upper bound of chaos, rendering them truly unique.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Additional Information:	Copyright of this article belong to AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	16 Jul 2018 16:19
Last Modified:	16 Jul 2018 16:19
URI:	http://eprints.iisc.ac.in/id/eprint/60186

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