Dynamics of a Heisenberg spin chain in the quantum critical regime: NMR experiment versus effective field theory

TL;DR

This study compares experimental NMR measurements of spin dynamics in a Heisenberg spin chain with theoretical predictions from Luttinger liquid theory, revealing strong effects of quantum criticality.

Contribution

It provides a detailed experimental-theoretical comparison of spin dynamics in a Heisenberg chain, confirming the applicability of Luttinger liquid theory in the quantum critical regime.

Findings

Excellent agreement between experiment and theory in the studied range.

Quantum critical point significantly influences spin dynamics.

Validates Luttinger liquid approach for describing low-energy excitations.

Abstract

A comprehensive comparison between the magnetic field- and temperature-dependent low frequency spin dynamics in the antiferromagnetic spin-1/2 Heisenberg chain (AFHC) system copper pyrazine dinitrate, probed via the 13C-nuclear magnetic resonance (NMR) relaxation rate 1/T1, and the field theoretical approach in the Luttinger liquid (LL) regime has been performed. We have found a very good agreement between the experiment and theory in the investigated temperature and field range. Our results demonstrate how strongly the quantum critical point affects the spin dynamics of Heisenberg spin chain compounds.