Reversing the weak measurement on a qubit

Abstract

Methods and systems are disclosed for restoring a state of a qubit transformed by a weak measurement to its original state. Unlike traditional methods, in which, the restoration was carried out by way of another weak measurement, the disclosed method uses an additional qubit, referred to as the ancillary qubit, and appropriate Hadamard and CNOT transformation for restoring the original state. Because the disclosed method avoids a second weak measurement, the time for restoration of the original state is considerably reduced.