Claims I wish I understood — quantum Darwinism
The resulting theory of Quantum Darwinism is relatively straightforward:
1) Human measurements are only one, rather unusual, means of forcing decoherence of a superposed or entangled quantum state into simpler states. The primary mechanism causing decoherence is the many types of interactions that the quantum system has with its environment. Typically quantum systems experience a vast number of such environmental interactions selectively destroying entangled quantum states.
2) As a result these environmental interactions, or environmental monitoring, only a small minority of quantum states, called pointer observables, are able to survive and evolve for any sustained period of time in the deterministic, classical manner of axiom 5 above. Their prolonged survival is due to the peculiar property of these pointer states that interactions with the environment and the subsequent decoherence leave them largely unchanged. They alone are able to survive in the face of environmental monitoring.
3) As the pointer states are the only ones able to survive decoherence, and as interactions with the environment pass information concerning the quantum state to the environment, a quantum system's environment becomes heavily imprinted with redundant copies of information concerning the quantum system's pointer states. It is these environmental copies that we actually experience and from which we gain information concerning quantum systems in almost all cases. For instance quantum systems are in continual interaction with the vast number of photons in their immediate environment. When we observe an object visually we are actually accessing information that has been imprinted on photons during previous interactions with the quantum system under observation.
4) The redundant imprinting of information in the environment makes this information available to multiple observers and provides the basis for our classical concept of objectivity or the ability of numerous observers to access and confirm the same information.
While this process may explain the emergence of classical physics from quantum physics it may not be clear where the Darwinian part comes in. Zurek explains his motivation in naming Quantum Darwinism:
Using Darwinian analogy, one might say that pointer states are most fit. They survive monitoring by the environment to leave descendants that inherit their properties. Classical domain of pointer states offers a static summary of the result of quantum decoherence. Save for classical dynamics, (almost) nothing happens to these einselected states, even though they are immersed in the environment.