Robust Control of Enantioselective State Transfer in Chiral Molecules

A robust coherent control strategy for enantioselective excitation in chiral molecules is presented. This approach employs a cyclic three-state rotational manifold, driven by three linearly polarized microwave fields, enabling analytical determination of the amplitude and phase requirements for enantioselective state transfer. To further enhance resilience against pulse-area errors, a composite pulse is introduced at a critical stage of the excitation process. This composite pulse minimizes pulse-area errors while maintaining enantioselectivity by precisely optimizing the subpulses' phases. As a demonstration, the scheme is applied to cyclohexylmethanol, a model chiral molecule. Numerical simulations reveal that the tailored microwave fields reliably steer the two enantiomers into distinct target states, and that the composite pulse markedly improves robustness. Importantly, the population of the enantiomer-specific target state remains above 0.99 even for pulse-area deviations of up to ±30%, representing a substantial improvement over single pulse protocols. These results highlight the potential of this method to achieve high fidelity enantioselective control, even in the presence of practical uncertainties in the control field.