Page "Quantum information" Paragraph 12

One of the strengths of classical information theory is that physical representation of information can be disregarded: There is no need for an ' ink-on-paper ' information theory or a ' DVD information ' theory.

This is because it is always possible to efficiently transform information from one representation to another.

However, this is not the case for quantum information: it is not possible, for example, to write down on paper the previously unknown information contained in the polarisation of a photon.