  Adiabatic passage of two correlated electrons in three coupled quantum dots
is shown to provide a robust and controlled way of distilling, transporting and
detecting spin entanglement, as well as of measuring the rate of spin
disentanglement. Employing tunable interdot coupling the scheme creates, from
an unentangled two-electron state, a superposition of spatially separated
singlet and triplet states. A single measurement of a dot population (charge)
collapses the wave function to either of these states, realizing entanglement
to charge conversion. The scheme is robust, with the efficiency close to 100%,
for a large range of realistic spectral parameters.
