Toolbox for reconstructing quantum theory from rules on information acquisition

Understand

We develop an operational approach for reconstructing the quantum theory of qubit systems from elementary rules on information acquisition.

• The focus lies on an observer O interrogating a system S with binary questions and S's state is taken as O's `catalogue of knowledge' about S.
• The mathematical tools of the framework are simple and we attempt to highlight all underlying assumptions.
• Four rules are imposed, asserting (1) a limit on the amount of information available to O; (2) the mere existence of complementary information; (3) O's total amount of information to be preserved in-between interrogations; and, (4) O's `catalogue of knowledge' to change continuously in time in-between interrogations and every consistent such evolution to be possible.