Discovery of Emergent Photon and Monopoles in a Quantum Spin Liquid

Abstract

Quantum spin liquid (QSL) is an exotic quantum phase of matter whose ground state is quantum-mechanically entangled without any magnetic ordering. A central issue concerns emergent excitations that characterize QSLs, which are hypothetically associated with quasiparticle fractionalization and topological order. Here we report highly unusual heat conduction generated by the spin degrees of freedom in a QSL state of the pyrochlore magnet Pr${}_2$Zr${}_2$O${}_7$, which hosts spin-ice correlations with strong quantum fluctuations. The thermal conductivity in high temperature regime exhibits a two-gap behavior, which is consistent with the gapped excitations of magnetic ($M$-) and electric monopoles ($E$-particles). At very low temperatures below 200\,mK, the thermal conductivity unexpectedly shows a dramatic enhancement, which well exceeds purely phononic conductivity, demonstrating the presence of highly mobile spin excitations. This new type of excitations can be attributed to emergent photons ($\nu$-particle), coherent gapless spin excitations in a spin-ice manifold.

arXiv comment5 pages, 6 figures

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Cited by in corpus (18)

• Frustrated quantum rare-earth pyrochlores
• Pinch Point Singularities of Tensor Spin Liquids
• Thermal Hall effects in quantum magnets
• Kitaev Quantum Spin Liquids
• Competing orders in pyrochlore magnets from a ${\mathbb{Z}}_2$ spin liquid perspective
• Magnetic field effects on the quantum spin liquid behaviors of NaYbS${}_2$
• Theory of magnetostriction for multipolar quantum spin ice in pyrochlore materials
• Spectroscopy of spinons in Coulomb quantum spin liquids
• Seeing beyond the light: Vison and photon electrodynamics in quantum spin ice
• Epitaxial stabilization of (111)-oriented frustrated quantum pyrochlore thin films
• Correlation holes and slow dynamics induced by fractional statistics in gapped quantum spin liquids
• Multi-scale Quantum Criticality driven by Kondo-lattice Coupling in Pyrochlore Systems
• Quantum percolation of monopole paths and the response of quantum spin ice
• Ultrasound detection of emergent photons in generic quantum spin ice
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• Spin-lattice Coupling in U(1) Quantum Spin Liquids
• Finite-momentum energy dynamics in a Kitaev magnet
• Quantum Spin Liquids in Pyrochlore Magnets With Non-Kramers Local Moments