Non-trivial effects of sourceless forces for spinors: toward an Aharonov–Bohm gravitational effect?Luca Fabbri, Flora Moulin and Aurélien BarrauEur. Phys. J. C, 79 10 (2019) 875DOI: https://doi.org/10.1140/epjc/s10052-019-7380-5