Trimer quantum spin liquid in a honeycomb array of Rydberg atoms

Quantum spin liquids are paradigmatic strongly correlated quantum states, but they have long eluded physical realizations. Only recently, the direct signatures of topological Z₂ spin liquids have been observed in a ruby Rydberg array. Here, we propose a concrete realization of a distinct class of spin liquids with fundamentally different excitations --- the gapless spin liquid --- in the honeycomb array of Rydberg atoms. We show that the honeycomb lattice maps to a classical trimer model on the triangular lattice in the regime where the third-nearest-neighbor atoms are within the blockade radius. We explore the quantum phase diagram of the model using both the density matrix renormalization group and exact diagonalization simulations. Most intriguingly, we find that, with quantum fluctuations, a novel trimer quantum spin liquid ground state appears. The fidelity of the trimer spin liquid states can be enhanced with dynamical preparation, and we explain the universal fidelity enhancement by a Rydberg-blockade projection mechanism associated with the smooth off-ramp. Finally, we discuss the robustness of the trimer spin liquid under realistic experimental parameters and demonstrate that our proposal can be readily implemented in current Rydberg atom quantum simulators.