Voltage profile and four terminal resistance of an interacting quantum wire

We investigate the behavior of the four-terminal resistance $R_{4pt}$ in a quantum wire described by a Luttinger liquid in two relevant situations: (i) in the presence of a single impurity within the wire and (ii) under the effect of asymmetries introduced by dirty voltage probes. In the first case, interactions leave a signature in a power law behavior of $R_{4pt}$ as a function of the voltage $V$ and the temperature $T$. In the second case interactions tend to mask the effect of the asymmetries. In both scenarios the occurrence of negative values of $R_{4pt}$ is explained in simple terms.