Decoherence, einselection, and the quantum origins of the classical

Decoherence is caused by the interaction with the environment. Environment certain observables of the system, destroying interference between the states corresponding to their eigenvalues. This leads to-induced superselection or einselection, a quantum process with selective loss of information. Einselected pointer states are. They can retain correlations with the rest of the Universe in spite of environment. Einselection enforces classicality by imposing an effective on the vast majority of the Hilbert space, eliminating especially the non-local "Schr\\"odinger cat" states. Classical structure of phase emerges from the quantum Hilbert space in the appropriate macroscopic: Combination of einselection with dynamics leads to the idealizations of point and of a classical trajectory. In measurements, einselection replaces entanglement between the apparatus and the measured system with the correlation.