Group Seminar

Quantum spin liquids are often viewed as delicate phases whose properties depend sensitively on the microscopic lattice geometry and exchange pattern. In this talk, I will discuss recent work suggesting a different perspective: apparently distinct frustrated spin-1/2 antiferromagnets can realize the same underlying quantum phase. I will focus on the square-lattice J1-J2 Z2​ Dirac spin liquid. The numerical signatures include level-crossing diagnostics, wavefunction overlaps, variational energetics, spin correlations, and dynamical structure factors consistent with Dirac spinon excitations. I will then describe how this lattice-level connection is mirrored in the low-energy field theory. The spin liquids on these different lattices descend from a common SU(2) pi-fux parent state and are described by Dirac fermions coupled to gauge and Higgs fields. This provides a unified framework for understanding the neighboring Néel and valence-bond-solid phases, as well as their confinement transitions, in terms of fermionic deconfined criticality. More broadly, the results suggest that quantum spin liquids may be more naturally classified by their emergent gauge structure than by microscopic lattice geometry alone.