Spin many-body phases in standard and topological waveguide QED simulators

TL;DR

This paper explores the diverse many-body phases in waveguide QED-based quantum spin models, revealing novel phases like symmetry-protected topological states with large-period magnetic orderings, expanding understanding beyond traditional platforms.

Contribution

It provides a comprehensive analysis of ground states in waveguide QED spin models, identifying new many-body phases and proposing measurement methods to detect them.

Findings

Discovery of symmetry-protected topological phases with large-period magnetic orderings

Identification of tunable interactions leading to novel many-body states

Proposed measurement protocols for experimental detection

Abstract

Quantum spin models find applications in many different areas, such as spintronics, high-Tc superconductivity, and even complex optimization problems. However, studying their many-body behaviour, especially in the presence of frustration, represents an outstanding computational challenge. To overcome it, quantum simulators based on cold, trapped atoms and ions have been built, shedding light already on many non-trivial phenomena. Unfortunately, the models covered by these simulators are limited by the type of interactions that appear naturally in these systems. Waveguide QED setups have recently been pointed out as a powerful alternative due to the possibility of mediating more versatile spin-spin interactions with tunable sign, range, and even chirality. Yet, despite their potential, the many-body phases emerging from these systems have only been scarcely explored. In this manuscript, we fill this gap analyzing the ground states of a general class of spin models that can be obtained in such waveguide QED setups. Importantly, we find novel many-body phases different from the ones obtained in other platforms, e.g., symmetry-protected topological phases with large-period magnetic orderings, and explain the measurements needed to probe them.