Diffraction and interference of walking drops

A decade ago, Yves Couder and Emmanuel Fort discovered a wave-particle association on the macroscopic scale: a drop can bounce~indefinitely on a vibrating bath of the same liquid and can be piloted by the~waves that it generates. These walking droplets~have~been shown to~exhibit several quantum-like features, including single-particle diffraction and interference.~Recently, the original~diffraction and interference experiments of Couder and Fort (Couder, Y. {\&} Fort, E.~\textit{Phys. Rev. Lett.}~\textbf{97}, 154101 (2006)) have been~revisited and contested~(Andersen, A.~\textit{et al. Phys. Rev. E}~\textbf{92}(1) 013006 (2015)). We~have~revisited~this system~using~an~improved~experimental set-up,~and~observed a~strong dependence of the behavior on system parameters, including drop size and vibrational~forcing. ~In both the single-~and the double-slit~geometries, the~diffraction pattern is dominated~by the interaction of the walking~droplet with a planar boundary.~Critically, in the~double-slit geometry, the walking droplet is influenced by both slits by virtue of its spatially~extended wave field.