|Title||Entanglement-assisted alignment of reference frames using a dense covariant coding|
|Publication Type||Journal Article|
|Year of Publication||2004|
|Authors||Bagan, E, Baig, M, Muñoz-Tapia, R|
|Journal||Physical Review A (Atomic, Molecular, and Optical Physics)|
We present a procedure inspired by dense coding, which enables a highly efficient transmission of information of a continuous nature. The procedure requires the sender and the recipient to share a maximally entangled state. We deal with the concrete problem of aligning reference frames or trihedra by means of a quantum system. We find the optimal covariant measurement and compute the corresponding average error, which has a remarkably simple close form. The connection of this procedure with that of estimating unitary transformations on qubits is briefly discussed.