 Since \(\alpha\) and \(\beta\) are complex and therefore continuous variables one might think that a single qubit is capable of storing an infinite amount of information. When measured, however, it yields only the classical result (0 or 1) with certain probabilities specified by the quantum state. In other words, the measurement changes the state of the qubit, “collapsing” it from a superposition to one of its terms. In fact one can prove (Holevo 1973) that the amount of information actually retrievable from a single qubit (what Timpson (2013, 47ff.) calls its “accessible information”) is no more than one bit. If the qubit is not measured, however, the amount of “hidden” information it “stores” (what Timpson calls its “specification information”) is conserved under its (unitary) dynamical evolution. This feature of quantum mechanics allows one to manipulate the information stored in unmeasured qubits with quantum gates (i.e. unitary transformations), and is one of the sources for the putative power of quantum computers.