Towards ultracold molecular qubits with Rydberg atom readout

Ultracold polar molecules have emerged as a promising platform for exploring quantum simulation of matter and quantum computation due to their rich internal structures and long-range dipole-dipole interactions. Our lab has recently achieved fast entanglement and the iSWAP gate [1], as well as a long coherence time for the rotational states of NaCs molecules assembled in an optical tweezer array. These results were enabled by the magic ellipticity of optical tweezers, as well as site-selective preparation and multi-state readout of molecules. So far, the readout has relied on reverse STIRAP, followed by the detection of the constituent atoms. Here, we explore a new approach with Rydberg atoms, where Cs atoms serve as ancillas for the non-destructive readout of molecular qubits.

[1] Picard et al., Nature 637, 821–826 (2025)