Quantum Spin Liquids

TL;DR

Quantum spin liquids are highly entangled quantum states with unique topological and non-local properties, challenging traditional magnetic order and offering insights into complex many-body quantum phenomena.

Contribution

This review synthesizes theoretical models, classifications, and experimental approaches to understanding quantum spin liquids, highlighting their distinct phases and properties.

Findings

Quantum spin liquids exhibit non-local excitations and topological order.

Gauge theory and parton methods are key tools in their study.

Experimental efforts are ongoing to identify and characterize these states.

Abstract

Quantum spin liquids may be considered "quantum disordered" ground states of spin systems, in which zero point fluctuations are so strong that they prevent conventional magnetic long range order. More interestingly, quantum spin liquids are prototypical examples of ground states with massive many-body entanglement, of a degree sufficient to render these states distinct phases of matter. Their highly entangled nature imbues quantum spin liquids with unique physical aspects, such as non-local excitations, topological properties, and more. In this review, we discuss the nature of such phases and their properties based on paradigmatic models and general arguments, and introduce theoretical technology such as gauge theory and partons that are conveniently used in the study of quantum spin liquids. An overview is given of the different types of quantum spin liquids and the models and theories used to describe them. We also provide a guide to the current status of experiments to study quantum spin liquids, and to the diverse probes used therein.