Figure 3

Parallelization schemes. Some computational tasks require the application of the same unitary operation to multiple path modes. (a) One can consider n different quantum systems \(S_{j}\), each in a separate path and subjected to a local unitary \(U_{O}\). (b) A qualitatively different scenario is that of a single quantum system that propagates along a superposition of multiple paths \(p_{i}\) and is subjected to an operation U that acts only on its internal degree of freedom (such as OAM). (c) The series of identical devices \(U_{O}\) acting on the internal degree of freedom can be replaced by a parallelized scheme of Eq. (14)