Seminarium Optyczne

Quantum photonics has seen rapid developments during recent years. The fundamentaldevelopments have been honoured with this year’s Nobel Prize in Physics, but since thenprogress has accelerated. To date, researchers routinely create multi-photon entangled statesin their laboratories, measure with unequal precision, communicate securely over longdistances, and have even demonstrated a computational quantum advantage.The main bottle necks that quantum photonics is facing at this point are non-deterministic operations and losses. In discrete variable quantum optics, the latter roughlyamount to the prior, as photon loss usually means an unsuccessful operation. Multiplexingstrategies are known to provide a solution to this problem. One particularly appealingmultiplexing method is time-multiplexing, whereby hardware components are used manytimes. This leads to an advantageous decrease in experimental overhead when compared to,e.g., spatial multiplexing where simply many components are built and used in parallel.In this presentation, I will discuss our recent work on time-multiplexed photonicquantum systems with active feed-forward and quantum feedback. Our experimental toolboxhas enabled us to demonstrate an exponential increase in the generation rate of multi-photonGHZ states which can form the basis for photonic quantum computing architectures, anincreased generation rate of multi-photon Fock states with the potential to create more exoticquantum states, and flexible high-dimensional quantum systems with up to 10 photons in upto 64 modes.