Conceptual inadequacy of the Shannon information in quantum measurements

The conceptual difficulties in defining information gain with Shannon's information in a quantum measurement were discussed. The study showed that the information content of a quantum system possessed some nonphysical properties. These difficulties arised because quantum measurements do not reveal a property of the individual quantum system existing before the measurement is performed. A measure of information in quantum mechanics was proposed that differs from Shannon's measure of information. Probability for various events to occur were to be considered before performing experiment. Under unitary transformations, the information content of a quantum system was invariant. Also, total information content can be conserved in time, avoiding the information.