Arnaud RALKO. “Exploring Quantum Spin Liquids: Fractionalized Excitations and Emergent Orders”
Summary :
Quantum spin liquids are exotic phases of matter that evade classical magnetic order due to strong quantum fluctuations, exhibiting long-range entanglement and fractionalized excitations. Their unique properties challenge conventional paradigms and offer insights into emergent gauge fields and topological order. Describing such highly entangled phases requires theoretical frameworks that go beyond traditional spin-wave or mean-field approaches, making parton-based theories particularly powerful tools.
We employ generalized Schwinger boson theories to investigate the ground state properties and the spin dynamics of two frustrated systems: In the spin 1/2 J1-J2-J3 kagome antiferromagnet, fractionalized excitations are revealed by the emergence of quantum half-moons in the dynamical structure factor [1]. In the spin-1 Heisenberg-Kitaev model [2], we uncover a chiral quantum spin liquid with spontaneously broken time-reversal symmetry having specific dynamics. These results unveil the diverse and subtle collective excitations that arise in frustrated quantum magnets and are naturally captured within these approaches.
[1] Phys. Rev. B 106, L140404 (2022).
[2] Phys. Rev. B 110, 134402 (2024).