Figure 3
From: Hyper-parallel photonic quantum computation with coupled quantum dots
Schematic diagram for a spatial-polarization hyper-CNOT gate operating on both the spatial-mode and the polarization DOFs of a two-photon system.
i1 and i2 represent the two spatial modes of photon a or b. Ui (i = 1, 2) represents a wave plate which is used to perform a polarization phase-flip operation U = −|R〉〈R| − |L〉〈L| on a photon.
