  Protocols for probabilistic entanglement-assisted quantum teleportation and
for entanglement swapping of material qubits are presented. They are based on a
protocol for postselective Bell-state projection which is capable of projecting
two material qubits onto a Bell state with the help of ancillary coherent
multiphoton states and postselection by balanced homodyne photodetection.
Provided this photonic postselection is successful we explore the theoretical
possibilities of realizing unit fidelity quantum teleportation and entanglement
swapping with $25\%$ success probability. This photon-assisted Bell projection
is generated by coupling almost resonantly the two material qubits to single
modes of the radiation field in two separate cavities in a Ramsey-type
interaction sequence and by measuring the emerged field states in a balanced
homodyne detection scenario. As these quantum protocols require basic tools of
quantum state engineering of coherent multiphoton states and balanced homodyne
photodetection they may offer interesting perspectives in particular for
current quantum optical applications in quantum information processing.
