  We use the Unruh effect to investigate how the teleportation of quantum
states is affected when one of the entangled qubits used in the process is
under the influence of some external force. In order to reach a comprehensive
understanding, a detailed analysis of the acceleration effect on such entangled
qubit system is performed. In particular, we calculate the mutual information
and concurrence between the two qubits and show that the latter has a ``sudden
death" at a finite acceleration, whose value will depend on the time interval
along which the detector is accelerated.
