The general topic of the GDR MESO is the study of the quantum properties of conductors, mainly using transport techniques which provide information about the wave-like nature of the charge carriers, but also with current noise measurements which shed light onto their particle-like nature and hence on the statistics of these carriers. In the last few years, local probe techniques have emerged (capacitance, tunnel transport, …) but also finite frequency measurements (to reach the regime in which the excitation frequency can be of the same order as the characteristic circuit frequencies) or hybrid experiments combining optical and transport tools. Most of the experiments probe low-energy scales (below about 100µeV and at very low temperature 10-100mK)

The GDR is mainly focused on “basic science” but is also interested in possible applications. In particular, we can expect that our work will have applications in quantum information. With the current scaling of electronic devices, the latter will reach dimensions for which quantum effects have important consequences. The research on quantum bits, with the perspective of building a quantum computer, has allowed one to understand many effects responsible for the loss of quantum coherence. Another very important point is the emergence of new types of materials or topological matter. Graphene is one of the best examples in which the progress realized in the fabrication of high-mobility samples have permitted to demonstrate resistance standards for metrology that are based on the quantum Hall effect, without needing any cooling below 4K.
The basic challenges of the GDR MESO can be grouped into 4 topics:

1- Transport and coherent manipulation of charge, heat and spin in mesoscopic systems
2- Hybrid systems and topological matter
3- Mesoscopic probes for quantum materials
4- Mesoscopic quantum devices

The latest theoretical and experimental tools allow one to probe systems in new limits, beyond the perturbative limit. One of the challenges of our GDR is to promote a scientific culture allowing to address quantum systems with a transverse approach, combining perspectives from different communities.