PREFERRED BASIS IN THE MANY-WORLDS INTERPRETATION OF QUANTUM-MECHANICS AND QUANTUM COSMOLOGY

The authors revive an old proposal of Zeh (1986) for the preferred basis in the many-worlds interpretation of quantum mechanics. The algorithm for this basis reduces to the eigenvalue problems for density matrices of subsystems splitting the quantum system into the observer and the observable counterpart. A semiclassical calculational method for these eigenvalue problems is developed and the dynamical properties of the preferred basis are investigated. Applications of this proposal to quantum cosmology are discussed.