Efforts to develop quantum computers are motivated by the promise of a tremendous speedup in several computational tasks such as quantum simulation or factoring. A milestone in this quest will be to provide evidence of quantum supremacy, which occurs when a quantum device solves a family of problems faster than state-of-the-art classical computers. The technological race toward this achievement goes hand in hand with the development of classical protocols that can discern genuine quantum processes. Here, we provide a step forward in this direction by presenting a machine-learning algorithm to detect malfunctions within a class of quantum hardware used to demonstrate quantum supremacy, relying only on experimental data.
Classical machine learning algorithms can provide insights on high-dimensional processes that are hardly accessible with conventional approaches. In this work we apply t-distributed Stochastic Neighbor Embedding (t-SNE) to probe the spatial distribution of n-photon events in m-dimensional Hilbert spaces, showing that its findings can be beneficial for validating genuine quantum interference in boson sampling experiments. We envisage that this approach will inspire further theoretical investigations, for instance for a reliable assessment of quantum computational advantage.
Bosonic interference is a fundamental physical phenomenon, and it is believed to lie at the heart of quantum computational advantage. Here we describe how linear interferometers can be used to unambiguously witness genuine n-boson indistinguishability. Our approach results in a convenient tool for practical photonic applications, and may inspire further fundamental advances based on the operational framework we adopt.
3D nano-optical devices created directly inside dielectric crystals like YAG and sapphire by exploiting femtosecond laser pulses. This discovery is very important, because to date, through the conventional techniques of micro- and nano-processing, it is only possible to modify these crystals on their surface, thus obtaining purely 2D structures. These results pave the way for the development of new-generation photonic devices.
Experimental implementation of a reconfigurable integrated multimode interferometer designed for simultaneous estimation of two optical phases. We verify the high-fidelity operation of the implemented device and demonstrate quantum-enhanced performances in two-phase estimation with respect to the best classical case, post-selected to the number of detected coincidences. This device can be employed to test general adaptive multiphase protocols due to its high reconfigurability level, and represents a powerful platform to investigate the multiparameter estimation scenario.
Professor Gérard Mourou, Nobel Laureate in Physics 2018, was a guest of the Politecnico di Milano, where he held the lectio magistralis entitled “Passion for extreme light”, the first after his proclamation in October 2018. The event was jointly organized by the Department of Physics and by the CNR-IFN.
Roberto Osellame has been nominated OSA Fellow in the 2019 class with the motivation ‘For pioneering and outstanding contributions to femtosecond laser micromachining of transparent materials with applications to optical communications, optofluidics and integrated quantum photonics’.
Roberto Osellame is giving an invited talk at Photonics Asia 2018 in Beijing (China) on Thursday 11 October about ‘Integrated quantum photonics in femtosecond-laser-written circuits’.
Quantum interference between two single photons coupled to topologically protected states realized in femtosecond laser written waveguide arrays. Collaboration with RMIT in Melbourne (Australia) – Alberto Peruzzo’s group.
Our work on single-photon quantum memory in femtosecond-laser-written waveguides in Pr:YSO is displayed on the journal cover of Optica.