Quasiprobability distributions have played an important role in the development of quantum mechanics from its beginnings. The Wigner function and the phase-space formulation of quantum mechanics played and continue to play a crucial role in the development of quantum mechanics and quantum information theory over the last few decades. 

This conference on Quasiprobability distributions in quantum mechanics, optics and information (QuiDiQua) is focused on phase-space representations in quantum mechanics and continuous-variable quantum information, in particular its quantum optical implementations. It covers both theoretical and experimental sides of this research area. It will bring together physicists and mathematicians studying all aspects of the use of quasiprobabilities in quantum mechanics, as well as of their recent applications in quantum information theory and quantum metrology. This is the fourth in a series of conferences, the first three of which took place in Lille in 2023, in Milan in 2024 and in Paris in 2025. This is a revival of an earlier workshop series, which took place from 2002 to 2013, called CVQIP (Continuous-variable quantum information processing).