• Gardner, J. S., Gingras, M. J. P. & Greedan, J. E. Magnetic pyrochlore oxides. Rev. Mod. Phys. 82, 53–107 (2010).

    Article 
    ADS 

    Google Scholar
     

  • Savary, L. & Balents, L. Quantum spin liquids: a review. Rep. Prog. Phys. 80, 016502 (2017).

    Article 
    ADS 

    Google Scholar
     

  • Zhou, Y., Kanoda, K. & Ng, T.-K. Quantum spin liquid states. Rev. Mod. Phys. 89, 025003 (2017).

    Article 
    ADS 
    MathSciNet 

    Google Scholar
     

  • Hallas, A. M., Gaudet, J. & Gaulin, B. D. in Annual Review of Condensed Matter Physics Vol. 9 (eds Sachdev, S. & Marchetti, M. C.) 105–124 (Annual Reviews, 2018).

  • Broholm, C. et al. Quantum spin liquids. Science 367, eaay0668 (2020).

    Article 

    Google Scholar
     

  • Anderson, P. W. Resonating valence bonds: a new kind of insulator? Mater. Res. Bull. 8, 153–160 (1973).

    Article 

    Google Scholar
     

  • Anderson, P. W. The resonating valence bond state in La2CuO4 and superconductivity. Science 235, 1196–1198 (1987).

    Article 
    ADS 

    Google Scholar
     

  • Lee, P. A., Nagaosa, N. & Wen, X. G. Doping a Mott insulator: physics of high-temperature superconductivity. Rev. Mod. Phys. 78, 17–85 (2006).

    Article 
    ADS 

    Google Scholar
     

  • Kitaev, A. Y. Fault-tolerant quantum computation by anyons. Ann. Phys. 303, 2–30 (2003).

    Article 
    ADS 
    MathSciNet 

    Google Scholar
     

  • Kitaev, A. Anyons in an exactly solved model and beyond. Ann. Phys. 321, 2–111 (2006).

    Article 
    ADS 
    MathSciNet 

    Google Scholar
     

  • Takagi, H., Takayama, T., Jackeli, G., Khaliullin, G. & Nagler, S. E. Concept and realization of Kitaev quantum spin liquids. Nat. Rev. Phys. 1, 264–280 (2019).

    Article 

    Google Scholar
     

  • Han, T. H. et al. Fractionalized excitations in the spin-liquid state of a kagome-lattice antiferromagnet. Nature 492, 406–410 (2012).

    Article 
    ADS 

    Google Scholar
     

  • Norman, M. R. Colloquium: herbertsmithite and the search for the quantum spin liquid. Rev. Mod. Phys. 88, 041002 (2016).

    Article 
    ADS 
    MathSciNet 

    Google Scholar
     

  • Shen, Y. et al. Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate. Nature 540, 559–562 (2016).

    Article 

    Google Scholar
     

  • Paddison, J. A. M. et al. Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4. Nat. Phys. 13, 117–122 (2016).

    Article 

    Google Scholar
     

  • Dai, P.-L. et al. Spinon Fermi surface spin liquid in a triangular lattice antiferromagnet NaYbSe2. Phys. Rev. 11, 021044 (2021).

    Article 

    Google Scholar
     

  • Balz, C. et al. Physical realization of a quantum spin liquid based on a complex frustration mechanism. Nat. Phys. 12, 942–947 (2016).

    Article 

    Google Scholar
     

  • Scheie, A. O. et al. Proximate spin liquid and fractionalization in the triangular antiferromagnet KYbSe2.Nat. Phys. 20, 74–79 (2024).

    Article 

    Google Scholar
     

  • Xie, T. et al. Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe2. npj Quantum Mater. 8, 48 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Scheie, A. et al. Witnessing entanglement in quantum magnets using neutron scattering. Phys. Rev. B 103, 224434 (2021).

    Article 
    ADS 

    Google Scholar
     

  • Sherman, N. E., Dupont, M. & Moore, J. E. Spectral function of the J1–J2 Heisenberg model on the triangular lattice. Phys. Rev. B 107, 165146 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Bramwell, S. T. & Gingras, M. J. P. Spin ice state in frustrated magnetic pyrochlore materials. Science 294, 1495–1501 (2001).

    Article 
    ADS 

    Google Scholar
     

  • Bramwell, S. T. & Harris, M. J. The history of spin ice. J. Phys. Condens. Matter 32, 374010 (2020).

    Article 

    Google Scholar
     

  • Fennell, T. et al. Magnetic Coulomb phase in the spin ice Ho2Ti2O7. Science 326, 415–417 (2009).

  • Gingras, M. J. P. & McClarty, P. A. Quantum spin ice: a search for gapless quantum spin liquids in pyrochlore magnets. Rep. Prog. Phys. 77, 056501 (2014).

    Article 
    ADS 

    Google Scholar
     

  • Hermele, M., Fisher, M. P. A. & Balents, L. Pyrochlore photons: the U⁡(1) spin liquid in a S = 1/2 three-dimensional frustrated magnet. Phys. Rev. B 69, 064404 (2004).

    Article 
    ADS 

    Google Scholar
     

  • Banerjee, A., Isakov, S. V., Damle, K. & Kim, Y. B. Unusual liquid state of hard-core bosons on the pyrochlore lattice. Phys. Rev. Lett. 100, 047208 (2008).

    Article 
    ADS 

    Google Scholar
     

  • Huang, C.-J., Deng, Y., Wan, Y. & Meng, Z. Y. Dynamics of topological excitations in a model quantum spin ice. Phys. Rev. Lett. 120, 167202 (2018).

    Article 
    ADS 

    Google Scholar
     

  • Kato, Y. & Onoda, S. Numerical evidence of quantum melting of spin ice: quantum-to-classical crossover. Phys. Rev. Lett. 115, 077202 (2015).

    Article 
    ADS 

    Google Scholar
     

  • Benton, O., Sikora, O. & Shannon, N. Seeing the light: experimental signatures of emergent electromagnetism in a quantum spin ice. Phys. Rev. B 86, 075154 (2012).

    Article 
    ADS 

    Google Scholar
     

  • Shannon, N., Sikora, O., Pollmann, F., Penc, K. & Fulde, P. Quantum ice: a quantum Monte Carlo study. Phys. Rev. Lett. 108, 067204 (2012).

    Article 
    ADS 

    Google Scholar
     

  • Pace, S. D., Morampudi, S. C., Moessner, R. & Laumann, C. R. Emergent fine structure constant of quantum spin ice is large. Phys. Rev. Lett. 127, 117205 (2021).

    Article 
    ADS 

    Google Scholar
     

  • Savary, L. & Balents, L. Coulombic quantum liquids in spin-1/2 pyrochlores. Phys. Rev. Lett. 108, 037202 (2012).

    Article 
    ADS 

    Google Scholar
     

  • Ross, K. A., Savary, L., Gaulin, B. D. & Balents, L. Quantum excitations in quantum spin ice. Phys. Rev. 1, 021002 (2011).

    Article 

    Google Scholar
     

  • Thompson, J. D. et al. Quasiparticle breakdown and spin Hamiltonian of the frustrated quantum pyrochlore Yb2Ti2O7 in a magnetic field. Phys. Rev. Lett. 119, 057203 (2017).

    Article 
    ADS 

    Google Scholar
     

  • Sibille, R. et al. Experimental signatures of emergent quantum electrodynamics in Pr2Hf2O7. Nat. Phys. 14, 711–715 (2018).

    Article 

    Google Scholar
     

  • Scheie, A. et al. Multiphase magnetism in Yb2Ti2O7. Proc. Natl Acad. Sci. USA 117, 27245–27254 (2020).

    Article 
    ADS 

    Google Scholar
     

  • Gaudet, J. et al. Quantum spin ice dynamics in the dipole-octupole pyrochlore magnet Ce2Zr2O7. Phys. Rev. Lett. 122, 187201 (2019).

  • Gao, B. et al. Experimental signatures of a three-dimensional quantum spin liquid in effective spin-1/2 Ce2Zr2O7 pyrochlore. Nat. Phys. 15, 1052–1057 (2019).

  • Sibille, R. et al. Candidate quantum spin liquid in the Ce3+ pyrochlore stannate Ce2Sn2O7. Phys. Rev. Lett. 115, 097202 (2015).

  • Sibille, R. et al. A quantum liquid of magnetic octupoles on the pyrochlore lattice. Nat. Phys. 16, 546–552 (2020).

    Article 

    Google Scholar
     

  • Smith, E. M. et al. The case for a U(1) quantum spin liquid ground state in the dipole-octupole pyrochlore Ce2Zr2O7. Phys. Rev. X 12, 021015 (2022).

  • Porée, V. et al. Crystal-field states and defect levels in candidate quantum spin ice Ce2Hf2O7. Phys. Rev. Mater. 6, 044406 (2022).

  • Porée, V. et al. Dipolar-octupolar correlations and hierarchy of exchange interactions in Ce2Hf2O7. Preprint at https://arxiv.org/abs/2305.08261 (2023).

  • Yahne, D. R. et al. Dipolar spin ice regime proximate to an all-in-all-out Néel ground state in the dipolar-octupolar pyrochlore Ce2⁢Sn2⁢O7. Phys. Rev. X 14, 011005 (2024).

  • Huang, Y.-P., Chen, G. & Hermele, M. Quantum spin ices and topological phases from dipolar-octupolar doublets on the pyrochlore lattice. Phys. Rev. Lett. 112, 167203 (2014).

    Article 
    ADS 

    Google Scholar
     

  • Li, Y.-D. & Chen, G. Symmetry enriched U(1) topological orders for dipole-octupole doublets on a pyrochlore lattice. Phys. Rev. B 95, 041106 (2017).

    Article 
    ADS 

    Google Scholar
     

  • Benton, O. Ground-state phase diagram of dipolar-octupolar pyrochlores. Phys. Rev. B 102, 104408 (2020).

    Article 
    ADS 

    Google Scholar
     

  • Bhardwaj, A. et al. Sleuthing out exotic quantum spin liquidity in the pyrochlore magnet Ce2Zr2O7. npj Quantum Mater. 7, 51 (2022).

  • Hosoi, M., Zhang, E. Z., Patri, A. S. & Kim, Y. B. Uncovering footprints of dipolar-octupolar quantum spin ice from neutron scattering signatures. Phys. Rev. Lett. 129, 097202 (2022).

    Article 
    ADS 

    Google Scholar
     

  • Desrochers, F., Chern, L. E. & Kim, Y. B. Symmetry fractionalization in the gauge mean-field theory of quantum spin ice. Phys. Rev. B 107, 064404 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Desrochers, F. & Kim, Y. B. Spectroscopic signatures of fractionalization in octupolar quantum spin ice. Phys. Rev. Lett. 132, 066502 (2024).

    Article 
    ADS 

    Google Scholar
     

  • Gao, B. et al. Magnetic field effects in an octupolar quantum spin liquid candidate. Phys. Rev. B 106, 094425 (2022).

    Article 
    ADS 
    MathSciNet 

    Google Scholar
     

  • Smith, E. M. et al. Quantum spin ice response to a magnetic field in the dipole-octupole pyrochlore Ce2Zr2O7. Phys. Rev. B 108, 054438 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Beare, J. et al. µSR study of the dipole-octupole quantum spin ice candidate Ce2Zr2O7. Phys. Rev. B 108, 174411 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Porée, V. et al. Evidence for fractional matter coupled to an emergent gauge field in a quantum spin ice. Nat. Phys. 21, 83–88 (2024).

    Article 

    Google Scholar
     

  • Moon, R. M., Riste, T. & Koehler, W. C. Polarization analysis of thermal-neutron scattering. Phys. Rev. 181, 920–931 (1969).

    Article 
    ADS 

    Google Scholar
     

  • Liu, P. et al. In-plane uniaxial pressure-induced out-of-plane antiferromagnetic moment and critical fluctuations in BaFe2As2. Nat. Commun. 11, 5728 (2020).

    Article 
    ADS 

    Google Scholar
     

  • Dai, P. Antiferromagnetic order and spin dynamics in iron-based superconductors. Rev. Mod. Phys. 87, 855–896 (2015).

    Article 
    ADS 
    MathSciNet 

    Google Scholar
     

  • Lee, S., Onoda, S. & Balents, L. Generic quantum spin ice. Phys. Rev. B 86, 104412 (2012).

    Article 
    ADS 

    Google Scholar
     

  • Chen, G. Spectral periodicity of the spinon continuum in quantum spin ice. Phys. Rev. B 96, 085136 (2017).

    Article 
    ADS 

    Google Scholar
     

  • Yao, X.-P., Li, Y.-D. & Chen, G. Pyrochlore U(1) spin liquid of mixed-symmetry enrichments in magnetic fields. Phys. Rev. Res. 2, 013334 (2020).

    Article 

    Google Scholar
     

  • Patri, A. S., Hosoi, M. & Kim, Y. B. Distinguishing dipolar and octupolar quantum spin ices using contrasting magnetostriction signatures. Phys. Rev. Res. 2, 023253 (2020).

    Article 

    Google Scholar
     

  • Wen, J. J. et al. Disordered route to the Coulomb quantum spin liquid: random transverse fields on spin ice in Pr2Zr2O7. Phys. Rev. Lett. 118, 107206 (2017).

    Article 
    ADS 

    Google Scholar
     

  • Kofu, M. et al. Magnetic boson peak in classical spin glasses. Phys. Rev. Res. 6, 013006 (2024).

    Article 

    Google Scholar
     

  • Matsumoto, Y. & Nakatsuji, S. Relaxation calorimetry at very low temperatures for systems with internal relaxation. Rev. Sci. Instrum. 89, 033908 (2018).

    Article 
    ADS 

    Google Scholar
     

  • Popa, K. et al. A re-evaluation of the heat capacity of cerium zirconate Ce2Zr2O7. J. Phys. Chem. Solids 69, 70–75 (2008).

    Article 
    ADS 

    Google Scholar
     

  • Lan, G., Ouyang, B. & Song, J. The role of low-lying optical phonons in lattice thermal conductance of rare-earth pyrochlores: a first-principle study. Acta Mater. 91, 304–317 (2015).

    Article 
    ADS 

    Google Scholar
     

  • Anderson, P. W., Halperin, B. I. & Varma, C. M. Anomalous low-temperature thermal properties of glasses and spin glasses. Philos. Mag.-J. Theor. Exp. Appl. Phys. 25, 1–9 (1972).


    Google Scholar
     

  • Binder, K. & Young, A. P. Spin glasses: experimental facts, theoretical concepts, and open questions. Rev. Mod. Phys. 58, 801–976 (1986).

    Article 
    ADS 

    Google Scholar
     

  • Ramirez, A. P., Espinosa, G. P. & Cooper, A. S. Strong frustration and dilution-enhanced order in a quasi-2D spin glass. Phys. Rev. Lett. 64, 2070–2073 (1990).

    Article 
    ADS 

    Google Scholar
     

  • Nakatsuji, S. et al. Spin disorder on a triangular lattice. Science 309, 1697–1700 (2005).

    Article 
    ADS 

    Google Scholar