Single-Shot Nondestructive Quantum Sensing for Gaseous Samples with Hundreds of Chiral Molecules

Chiral discrimination that is efficient at detecting tiny amounts of chiral substances, especially at the single-molecule level, is in great demand. Here, we propose a single-shot nondestructive quantum sensing method addressing such an issue. Our scheme consists of two steps. In the first step, the two enantiomers are prepared in different rotational states via microwave enantio-specific state transfer. Then, chiral discrimination is transferred to quantum hypothesis testing. In the second step, we for the first time introduce a nondestructive quantum-state detection technique assisted with a microwave resonator for chiral discrimination, through which the molecular chirality is determined by the sign of the output signals. Using a typical chiral molecule, 1,2-propanediol, and an experimentally feasible model based on spherical Fabry-Pérot cavity, we show that the molecular chirality of slowly moving enantiopure gaseous samples with 10²-10³ molecules can be highly credibly distinguished in a single-shot detection. By further trapping chiral molecules, it is promising to achieve chiral discrimination at the single-molecule level by using our approach.