Non-Fermi liquid induced by Bose metal with protected subsystem symmetries

TL;DR

This paper explores a new type of non-Fermi liquid in two dimensions, arising from interactions between fermions with quadratic band-touching and a Bose metal with subsystem symmetry, revealing a line of fixed points with continuously varying anomalous dimensions.

Contribution

It introduces a novel non-Fermi liquid phase in 2D induced by Bose metal interactions, characterized by a line of fixed points and variable fermionic anomalous dimensions.

Findings

Extended IR singularity leads to a line of non-Fermi liquid fixed points

Fermionic anomalous dimension varies continuously, similar to Luttinger liquids

Generalizations reveal additional unusual ground state features

Abstract

Understanding non-Fermi liquids in dimensions higher than one, has been a subject of great interest. Such phases may serve as parent states for other unconventional phases of quantum matter, in a similar manner that conventional broken symmetry states can be understood as instabilities of the Fermi liquid. In this work, we investigate the emergence of a novel non-Fermi liquid in two dimensions, where the fermions with quadratic band-touching dispersion interact with the Bose metal. The bosonic excitations in the Bose metal possess an extended nodal-line spectrum in momentum space, which arises due to the subsystem symmetry or the restricted motion of bosons. Using renormalization group analysis and direct computations, we show that the extended infrared (IR) singularity of the Bose metal leads to a line of interacting fixed points of novel non-Fermi liquids, where the anomalous dimension of the fermions varies continuously, akin to the Luttinger liquid in one dimension. Further, the generalization of the model with multiple low-energy excitations is used to explore other unusual features of the resulting ground state.