Research: Spectral Response of Disorder-Free Localized Lattice Gauge Theories

Identifying experimentally relevant signatures of localized phases of interacting systems has been an ongoing challenge over the past decade, especially in solid state systems. Commonly used probes such as the dynamical structure factor or other spatially averaged spectral functions fail to provide any unique signature for conventional many-body localization in disordered systems. Recent developments over the last few years have presented the possibility of localization in constrained many-body systems such as lattice gauge theories, in the absence of quenched disorder - a phenomena termed disorder-free localization. In our work we provide a spectral analysis of an interacting two-dimensional quantum many-body system displaying such localization. As our main result we show that the disorder-free localized phase has a unique signature in a commonly used probe in neutron scattering experiments for frustrated magnets – the dynamical structure factor. The transverse component of the structure factor displays a few sharp discrete peaks along with a vanishing response in the zero-frequency limit. We argue that such a response is robust in the infinite size limit and is a hallmark of the disorder-free localized phase.

N. Chakraborty, M. Heyl, P. Karpov, R. Moessner,
Spectral Response of Disorder-Free Localized Lattice Gauge Theories,
Phys. Rev. Lett. 131, 220402 (2023)