Generalized W-states and Quantum Communication Protocols

Abstract

We consider W-states and generalized W-states for $n$-qubit systems. We obtain conditions to use these states as quantum resources to teleport unknown states. Only a limited class of multi-qubit states can be teleported. For $one$-qubit states, we use protocols which are simple extensions of the conventional teleportation protocol. We also show that these resource states can be used to transmit {\em at most} $n + 1$ classical bits by sending $n$ qubits if the appropriate conditions are met. Therefore these states are not suitable for maximal teleportation or superdense coding when $ n > 3$.