I will consider the quantum transport in networks of weakly disordered metallic wires. Quantum interferences of time reversed trajectories are responsible for a small contribution to the conductance, known as the weak localization correction (WL). From the experimental point of view the study of the WL provides an efficient tool to probe phase coherence in weakly disordered metals. The WL is identified through its magnetic field dependence: for example, the conductance of a loop presents oscillations as a function of the flux with period $h/2e$, known as Altshuler-Aronov-Spivak (AAS) oscillations.
I will study how nonlocality of quantum transport affects the shape of AAS oscillations in networks (connected ring, chain of rings,…). This is important if one aims to extract the phase coherence length from analysis of AAS oscillations.
In a second part I will consider the effect of electron-electron interaction. Following the approach initiated by Altshuler, Aronov and Khmelnitzkii (AAK) to describe decoherence due to e-e interaction in an infinite wire, I will present some results for the AAS-harmonics dependence as a function of the Nyquist length in several networks.
Université d’Orsay