From spectroscopy to quantum dynamics: assessing reduced models of a NaCs molecular gate

arXiv:2611.08844v1 Announce Type: new Abstract: We investigate how spectroscopic calibration and basis selection affect predictions for a dipolar-exchange gate between two optically trapped $^{23}$Na$^{133}$Cs molecules. We construct a 128-state molecular Hamiltonian restricted to the $N=0,1$ rotational manifold, fit two effective optical parameters to three bright microwave transitions, and compare the resulting spectrum with four additional lines. In the coherent pair model, changing the optical polarization angle by $+0.1^\circ$ reduces the calculated gate fidelity from 94.64\% to 1.09\% at fixed carrier frequencies. Retuning the carriers and restoring the target Rabi frequencies recovers 89.31\%.