Liquid, glass or crystal in blockaded Rydberg atoms on a kagome lattice
In plain words
Atoms on a kagome lattice (corner-sharing triangles) that block their neighbours from being excited showed, in early calculations, a disordered region that might be a quantum spin liquid. Later calculations found glassy behaviour or no liquid at all.
Precise statement
H = sum_i (Omega/2) X_i - Delta n_i + sum_i<j (C_6/r_ij^6) n_i n_j on the kagome lattice, in the dense-excitation window between valence-bond-solid phases identified by Samajdar et al. (PNAS 2021). Determine the ground state there: $Z2$ spin liquid, glass-like state from many nearly degenerate solids, or a crystal. Answer: phase identification with topological entanglement entropy or order parameters from large-size numerics.
What would settle it
Large-scale quantum Monte Carlo or 2D tensor-network calculations with the full $1/r^{6}$ tails that agree on the phase in this window.
Status in the literature
Unverified note
Samajdar et al. (PNAS 2021, arXiv:2011.12295) found a large-entanglement regime with no local order; Yan et al. (PRL 130, 206501, 2023) found glassy behaviour, and recurrent neural network wave functions found no evidence of a spin liquid (Hibat-Allah et al., Commun. Phys. 2025).