Holographic Fermi and Non-Fermi Liquids with Transitions in Dilaton Gravity

TL;DR

This paper investigates the behavior of fermionic two-point functions in strongly coupled systems via holography, revealing transitions between Fermi liquid and non-Fermi liquid states influenced by dilaton gravity parameters.

Contribution

It introduces a holographic model with a dilaton field that captures transitions between Fermi and non-Fermi liquids in strongly coupled systems.

Findings

Identification of Fermi liquid behavior in certain parameter regimes.

Discovery of non-Fermi liquid behavior with broad excitations.

Observation of phase transitions characterized by changes in the two-point function.

Abstract

We study the two-point function for fermionic operators in a class of strongly coupled systems using the gauge-gravity correspondence. The gravity description includes a gauge field and a dilaton which determines the gauge coupling and the potential energy. Extremal black brane solutions in this system typically have vanishing entropy. By analyzing a charged fermion in these extremal black brane backgrounds we calculate the two-point function of the corresponding boundary fermionic operator. We find that in some region of parameter space it is of Fermi liquid type. Outside this region no well-defined quasi-particles exist, with the excitations acquiring a non-vanishing width at zero frequency. At the transition, the two-point function can exhibit non-Fermi liquid behaviour.