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Hydrodynamics in a Quantum Spin Chain

July 1, 2021

Scientific Achievement

Long wavelength spin fluctuations in a quantum spin chain correspond to superdiffusive classical hydrodynamics belonging to the Kardar-Parisi-Zhang (KPZ) universality class.

Significance and Impact

The presence of KPZ transport in the quantum limit provides a new way to understand the origins of strange fluid states in quantum materials.

(top) Neutron spectrum of KCuF3 at 300K. (bottom) The cut corresponding to the red bar, with the solid line showing power law behavior close to the predicted KPZ exponent.

Research Details

  • Spin fluctuations near Q=0 in the model material KCuF3 were measured using inelastic neutron scattering.
  • The intensity follows a power law close to Q-1.5, consistent with KPZ dynamics.
  • The data was compared to numerical simulations, and excellent agreement was found over all temperatures.

Related Publication: Scheie, A. et. al. (2021). Detection of Kardar-Parisi-Zhang Hydrodynamics in a Quantum Heisenberg Spin-1/2 Chain. Nature Physics, 17, 726-730.