Mobility edges through inverted quantum many-body scarring

TL;DR

This paper demonstrates the embedding of mobility edges within many-body localized spectra by constructing an 'inverted quantum many-body scar', revealing a new violation of the eigenstate thermalization hypothesis.

Contribution

It introduces the concept of inverted quantum many-body scars and shows how they can embed mobility edges in many-body localized systems.

Findings

Narrow window of highly entangled states in MBL spectrum

Embedding of mobility edges in MBL systems

Identification of inverted quantum many-body scars

Abstract

We show that the rainbow state, which has volume law entanglement entropy for most choices of bipartitions, can be embedded in a many-body localized spectrum. For a broad range of disorder strengths in the resulting model, we numerically find a narrow window of highly entangled states in the spectrum, embedded in a sea of area law entangled states. The construction hence embeds mobility edges in many-body localized systems. This can be thought of as the complement to many-body scars, an `inverted quantum many-body scar', providing a further type of setting where the eigenstate thermalization hypothesis is violated.