The context: We are in the solid state. After a photon absortion by a system with a singlet ground state, the system undergoes the spin-conserving fission of one spin singlet exciton into two spin triplet excitons (for context, see The entangled triplet pair state in acene and heteroacene materials). These spin triplet pair propagates in the solid, still entangled. The quantum-computing-related goal of all this operation would be to transfer the entanglement of the two flying qubits to two positions that are fixed in space and are also well protected from decoherence (low-energy excitations of nuclear spins in a paramagnetic ion, for example).
The problem at hand (1), and the question: What would be the requirements to favour said quantum information transfer between the flying qubits and the stationary qubits? (I know flying vs stationary qubit scenarios have been explored, but I have no experience in that field).