Early experimental evidence of a topological quantum state: The signature of the Haldane ground state revealed by scattered neutrons

TL;DR

This paper reviews early neutron scattering experiments that provided experimental evidence for the topological quantum ground state predicted by Haldane, challenging previous assumptions and confirming key theoretical ideas in quantum magnetism.

Contribution

It presents a historical review of neutron scattering experiments that identified the Haldane ground state, highlighting their significance in confirming topological quantum states.

Findings

Neutron scattering revealed signatures consistent with the Haldane ground state.

Experimental results challenged previous beliefs about quantum spin chains.

The work contributed to the validation of topological quantum theories.

Abstract

Neutron scattering played an important role in the experimental exploration of the theoretical ideas of Thouless, Haldane, and Kosterlitz, who won the Nobel Prize in Physics in 2016. This article reviews the signatures of Haldane's predicted topological quantum ground state and their observation in early neutron scattering experiments, which overturned the wisdom of the day.