  We propose schemes for generating spatially-separated spin entanglement in
systems of two quantum dots with onsite Coulomb repulsion weakly coupled to a
joint electron reservoir. An enhanced probability for the formation of spin
entanglement is found in nonequilibrium situations with one extra electron on
each dot, either in the transient state after rapid changes of the gate
voltage, or in the steady state with applied bias voltage. In both cases
so-called Werner states with spin singlet fidelity exceeding 1/2 are generated,
which indicates entanglement.

Mesoscale and Nanoscale Physics;Quantum Physics