Understanding electronic correlations remains one of the biggest challenges of theoretical condensed matter physics. Mesoscopic systems, where electronic confinement can be externally controlled, are natural test beds for understanding the effects of correlations, and the lack of proper techniques to take them into account is acute. This project aims at developing new tools for simulating correlated quantum mesoscopic devices. We will combine standard approaches for transport in mesoscopic quantum systems with new quantum Monte-Carlo algorithms designed to capture correlations in those devices. We will use modern programming paradigms to develop a versatile numerical platform designed to be easily used by other research groups. These numerical tools will be closely related to existing analytical approaches so that we shall be able to make contact with standard many-body theory while go beyond the limitations of the analytical approaches. We will apply this new set of techniques to several problems that have been puzzling the community for some time including quantum transport in low-density two-dimensional gases for both bulk disordered systems (“Two dimensional metal-insulator transition”) and quantum point contacts (“0.7 anomaly”). We will also apply our techniques to several new problems of increasing importance: at finite-frequency, electron-electron interactions play a central role and must be taken into account properly. We will discuss high frequency measurements such as quantum capacitances, ac conductance or photo-assisted transport in a variety of materials (twodimensional gases of electrons or holes, graphene, semi-conductor nanowires…) and leverage on our new numerical tools to go beyond the standard mean field description.