Realization schemes for quantum instruments in finite dimensions

Abstract

We present a general dilation scheme for quantum instruments with continuous outcome space in finite dimensions, in terms of a measurement on a finite-dimensional ancilla, described by a positive operator valued measure (POVM). The general result is then applied to a large class of instruments generated by operator frames, which contains group-covariant instruments as a particular case and allows one to construct dilation schemes based on a measurement on the ancilla followed by a conditional feed-forward operation on the output. In the case of tight operator frames, our construction generalizes quantum teleportation and telecloning, producing a whole family of generalized teleportation schemes in which the instrument is realized via a joint POVM at the sender combined with a conditional feed-forward operation at the receiver. © 2009 American Institute of Physics.