We have been learning about multi-qubit states, but we still don’t know what happens if we measure a qubit for the multi-qubit state. In this video, David will tell us about the generalized Born rule.

• To measure a multi-qubit state the qubit that we are going to measure needs to be expressed on the basis of measurement.
• The probability of getting the eigenvalue corresponding to this eigenvector of the measurement operator is given by the absolute value of the amplitude squared.
• The state of the qubit that we measured gets projected to the corresponding eigenvector, and the other qubit, the one we haven’t measured, is left in that state that it was accompanying.