Exchange Interaction Effects on the Conductance of Quantum Wires

The effect of exchange interaction on the two-terminal conductance of fully ballistic samples is studied using a many-particle wave packet formalism. The approach shows that the puzzling nonuniversal conductance quantization can be explained as a fermion exchange interaction effect. The Landauer conductance step Go is obtained when two-fermion interaction is considered. Reductions of Go are due to a many-particle exchange interaction effect. For ballistic GaAs/AlGaAs quantum wires longer than 1 um, a conductance step reduction is obtained in agreement with experimental results.