Quantum Darwinism and stability of the pointer states

It is a fundamental problem to explain the emergence of the objective classical world from the quantum world. The mechanism of quantum Darwinism asserts that, after the process of natural decoherence, the system becomes correlated with the environment such that each branch of the global wavefunction corresponds to a selected pointer (classical) state of the system. In this talk, we discuss the stability of pointer states upon observing the environment. In particular, we show that the post-measurement state of the system is almost surely one of the pointer states even when the environment is randomly measured, hence, objectivity of the pointer states is further justified.