  We investigate the entanglement between the spins of two quantum dots that
are not connected at once to the same system. Quantum entanglement between
localized spins is an essential property for the development of quantum
computing and quantum information. It is for this reason that generating and
controlling an entangled state between quantum dots received great attention in
the later years.
  In this work, we show that the information on the spin orientation of a
quantum dot can be kept, using the Kondo entanglement, in a reservoir of
electrons. Then, this information can be transmitted to another dot after the
first dot has been uncoupled from the reservoirs. We use a double quantum dot
system in a parallel geometry to construct the initial state, where each dot
interacts with reservoirs of different symmetries. We chose a phase in the
couplings to induce an antiferromagnetic spin correlation between the dots. The
time evolution of the initial state has been analyzed using the time-dependent
density matrix renormalization group method.
  We found that a partially entangled state between the dots can be obtained,
even if they are not connected at the same time. This entangled state is formed
just during the transient and is destroyed in the stationary state. The
stability of the state found in the transient is shown. To understand the
details of these phenomena, a canonical transformation of the real space is
used.
