  We study the quantum-jump-based feedback control on the entanglement shared
between two qubits with one of them subject to decoherence, while the other
qubit is under the control. This situation is very relevant to a quantum system
consisting of nuclear and electron spins in solid states. The possibility to
prolong the coherence time of the dissipative qubit is also explored. Numerical
simulations show that the quantum-jump-based feedback control can improve the
entanglement between the qubits and prolong the coherence time for the qubit
subject directly to decoherence.
