Fig. 3: Photonic implementation of quantum models of PMD processes.
From: Implementing quantum dimensionality reduction for non-Markovian stochastic simulation
We use a photonic setup to implement our quantum models. The orange region highlights the state preparation module, where two photons with a central wavelength of 808nm are generated via pumping a PPKTP crystal with temperature stabilised to around 35 °C through a type-II spontaneous parametric down-conversion process. One of the photons passes through a single-mode fibre and is prepared with an initial memory state encoded in its polarization, whilst the other is used as a trigger. The blue regions show the simulation module that carries out the evolution, encoding outputs into the photon path and updating the memory by rotating its polarisation (see Methods for details). After evolving two timesteps, the photon is passed into the tomography module (green region), where the output statistics are produced by photodetection counts, and the polarization is measured to tomographically reconstruct the final memory state. The optical components shown comprise PBS, polarising beamsplitter; M, mirror; IF, interference filter; QWP, quarter-wave plate; HWP, half-wave plate; FC, fibre coupler; BD, beam displacer; SPD, single photon detector.
