Geometric frustration produces long-sought Bose metal phase of quantum matter

TL;DR

This paper introduces a universal homogeneous theory for a Bose metal phase, arising from geometric frustration that confines quantum coherence, providing a new understanding of this elusive state of matter.

Contribution

It presents a novel intrinsic quantum Bose metal model based on geometric frustration, moving beyond impurity-based theories and explaining dissipative flow in bosonic systems.

Findings

Proposes a homogeneous theory for Bose metal driven by geometric frustration.

Describes a gapless insulator with dissipative flow vanishing at low energies.

Shows the Bose metal can exist under realistic experimental conditions.

Abstract

Two of the most prominent phases of bosonic matter are the superfluid with perfect flow and the insulator with no flow. A now decades-old mystery unexpectedly arose when experimental observations indicated that bosons could organize into the formation of an entirely different intervening third phase: the Bose metal with dissipative flow. The most viable theory for such a Bose metal to date invokes the use of the extrinsic property of impurity-based disorder; however, a generic intrinsic quantum Bose metal state is still lacking. We propose a universal homogeneous theory for a Bose metal in which geometric frustration confines the essential quantum coherence to a lower dimension. The result is a gapless insulator characterized by dissipative flow that vanishes in the low-energy limit. This failed insulator exemplifies a frustration-dominated regime that is only enhanced by additional scattering sources at low energy and therefore produces a Bose metal that thrives under realistic experimental conditions.