Flavored N=4 SYM -- a highly entangled quantum liquid

TL;DR

This paper investigates a holographic model of N=4 SYM with fundamental hypermultiplets at finite charge density, revealing a highly entangled quantum liquid with extensive flavor entanglement and unique entanglement entropy features.

Contribution

It introduces a new holographic quantum liquid model showing extensive flavor entanglement and unconventional entanglement entropy behavior compared to Fermi liquids.

Findings

Entanglement entropy shows volume law with shape dependence.

Flavor entanglement is extensive and more drastic than Fermi liquid expectations.

Finite temperature confines correlations to a region inversely proportional to temperature.

Abstract

We study N=4 SYM theory coupled to fundamental N=2 hypermultiplets in a state of finite charge density. The setup can be described holographically as a configuration of D3 and D7 branes with a non-trivial worldvolume gauge field on the D7. The phase has been identified as a new form of quantum liquid, where certain properties are those of a Fermi liquid while others are clearly distinct. We focus on the entanglement among the flavors, as quantified by the entanglement entropy. The expectation for a Fermi liquid would be a logarithmic enhancement of the area law, but we find a more drastic enhancement instead. The leading contributions are volume terms with a non-trivial shape dependence, signaling extensive entanglement among the flavors. At finite temperature these correlations are confined to a region of size given by the inverse temperature.