Quantum pump for spin and charge transport in a Luttinger liquid - art. no. 096401

We study two different parametric pumps-one for pumping spin currents, the other for charge currents-in interacting quantum wires. Ve find that, as a function of pumping frequency, the spin or charge pumped per cycle has a no nuniversal crossover-depending on pumping details-between two universal fix ed point values of 0 and twice the electronic spin or charge quantum number . The direction of flow between these two fixed points depends on whether t he interactions are repulsive or attractive, while the quantization itself is a signature of interactions.