Abstract Programmable quantum simulators based on neutral atom arrays today offer powerful platforms for studying strongly correlated phases of quantum matter. Here, we employ the projective symmetry group framework to describe the symmetry fractionalization patterns in a topologically ordered
Z2 Z 2 quantum spin liquid (QSL) synthesized in such a Rydberg array on the ruby lattice. By systematically comparing the static structure factors of all possible mean-field Ansätze against density-matrix renormalization group calculations, we identify a promising candidate for the precise
Z2 Z 2 QSL realized microscopically. We also present detailed analyses of the dynamical structure factors as a reference for future experiments and showcase how these spin correlations can differentiate between varied QSL Ansätze .
We study the uniform
U(1) quantum spin liquid (QSL) with low-energy fermionic quasiparticles for pyrochlore magnets with dipolar-octupolar symmetry, employing a fermionic parton mean-field theory approach. Self-consistent calculations stabilize 12 fully symmetric uniform
U(1) QSLs, of which four mean-field states are ``monopole-flux'' states. Several of these mean-field states show a linear temperature dependence of specific heat at low temperatures, the other phases show a power-law temperature dependence of specific heat $C\ensuremath{\sim}{T}^{\ensuremath{\alpha}}$. The linear temperature dependence of specific heat at low temperatures is reminiscent of the observations in
Nd2ScNbO7. We further compute the dynamic spin structure factors and discuss the possible signature of these fermionic spinons in neutron-scattering experiments.
Projective symmetry group classification of fermionic
Z2 spin liquids on the dipolar-octupolar pyrochlore magnets
We construct and classify
Z2 quantum spin liquids (QSLs) of fermionic partons on the dipolar-octupolar (DO) pyrochlore lattice. The DO pseudospin shares the space-group and time-reversal algebra of the effective spin-1/2 Kramers doublet, its projective symmetry group (PSG) yields the same 48 symmetric
Z2 classes as the generic fermionic classification. We show, the distinct DO symmetry action, encoded in a set of sublattice-independent operators, selects a physically different set of symmetry-allowed mean-field channels, so that the resulting ansatze, spinon spectra, and observables differ from both the effective spin-1/2 case and the bosonic DO classification. Decomposing the anisotropic XYZ exchange model into all symmetric singlet and triplet hopping and pairing channels and minimizing the mean-field energy self-consistently, we obtain phase diagrams in the (
Jx~,Jz~) plane in which only a few
Z2 states, several supporting gapless or flat-band spinon spectra, are stabilized. For these states we compute the spinon band structures, the low-temperature specific heat, and the dynamical spin structure factor, and we argue that the power-law specific-heat exponent is a diagnostic of the spinon nodal structure. A near-linear-in-temperature specific heat together with broad continua in the structure factor gives a fermionic-parton account of the gapless, fractionalized thermodynamics reported in DO materials such as
Nd2ScNbO7, complementing the bosonic quantum-spin-ice picture of the Ce-based compounds. The work extends the fermionic-parton classification of DO pyrochlore QSLs beyond the
U(1) sector, where
Z2 topological order is realized equally naturally by fermionic and bosonic spinons.