The collapse of wave function which accompanies measurements in standard quantum mechanics and the Schrödinger equation coexist as integral parts of the postulates of quantum mechanics. However, they represents two radically different ways for the state of a quantum mechanical system to evolve which are incompatible with each other. The von Neumann measurement scheme delayed the collapse of wave function by recognising the role of the measuring apparatus in a measurement and its interaction with the measured system, leading to a premeasurement stage. This leads to the famous measurement problem. The idea of pointer basis proposed by Zurek in 1981 provides a solution to the problem of the preferred basis, which is one side of the measurement problem. The highly redundantly record...[ Read more ]

The collapse of wave function which accompanies measurements in standard quantum mechanics and the Schrödinger equation coexist as integral parts of the postulates of quantum mechanics. However, they represents two radically different ways for the state of a quantum mechanical system to evolve which are incompatible with each other. The von Neumann measurement scheme delayed the collapse of wave function by recognising the role of the measuring apparatus in a measurement and its interaction with the measured system, leading to a premeasurement stage. This leads to the famous measurement problem. The idea of pointer basis proposed by Zurek in 1981 provides a solution to the problem of the preferred basis, which is one side of the measurement problem. The highly redundantly recorded system observables and the system’s pointer observables are shown to be one and the same set of observables in quantum Darwinism, which is based on measuring the information content contained in fragments of the environment about the system using tools from classical information theory. In 2017, Riedel gave a proposal on how to define records of redundantly recorded observables and built a scheme for branching of quantum states based upon these records. We analysed Riedel’s scheme analytically and tested it numerically on systems of identical fermions by casting the construction of the records into a maximisation problem of a multivariable function. We showed that Riedel’s scheme can only handle systems which are highly populated. However, questions regarding the nature and meaning of the records constructed from our numerical procedure remain.