Fermionic CFTs at large charge and large N

TL;DR

This paper investigates the large-charge sector of large-N fermionic conformal field theories in three dimensions, revealing two descriptions and confirming effective field theory predictions for phonon spectra.

Contribution

It provides explicit computations of conformal dimensions and distinguishes between superfluid and Fermi sphere descriptions in large-N fermionic CFTs.

Findings

Conformal dimensions of lowest fixed-charge operators are computed.

Two descriptions: superfluid and Fermi sphere, depending on model and charge.

EFT predictions for phonon spectrum are verified in the superfluid case.

Abstract

We study the large-charge sector of large-N fermionic CFTs in three dimensions. Depending on the model and the nature of the fixed charge, we find two types of descriptions: in terms of a superfluid or a Fermi sphere. We explicitly compute the conformal dimensions of the lowest operator of fixed charge and in the superfluid case verify the EFT predictions for the phonon spectrum.