On 5/22/2018 6:39 AM, [email protected] wrote:
I'm OK with getting rid of the projection operator. Are you now claiming information is lost or inaccessible in these orthogonal subspaces and therefore quantum measurements cannot be reversed?They are inaccessible to the people of any one world of the MWI. No! Irreversible FAPP! Think heat bath or Bucky Balls. https://en.wikipedia.org/wiki/Quantum_decoherence Examples of non-unitary modelling of decoherenceDecoherence <https://en.wikipedia.org/wiki/Decoherence> can be modelled as a non-unitary <https://en.wikipedia.org/wiki/Unitary_operator> process by which a system couples with its environment (although the combined system plus environment evolves in a unitary fashion).^[4] <https://en.wikipedia.org/wiki/Quantum_decoherence#cite_note-Lidar_and_Whaley-4> Thus the dynamics <javascript:void(0)> of the system alone, treated in isolation, are non-unitary and, as such, are represented by irreversible transformations <https://en.wikipedia.org/wiki/Irreversibility> acting on the system's Hilbert space <https://en.wikipedia.org/wiki/Hilbert_space>, H {\displaystyle {\mathcal {H}}} {\mathcal {H}}. Since the system's dynamics are represented by irreversible representations, then any information present in the quantum system can be lost to the environment or heat bath <https://en.wikipedia.org/wiki/Heat_bath>. Alternatively, the decay of quantum information caused by the coupling of the system to the environment is referred to as decoherence.^[3] <https://en.wikipedia.org/wiki/Quantum_decoherence#cite_note-Bacon-3> Thus decoherence is the process by which information of a quantum system is altered by the system's interaction with its environment (which form a closed system), hence creating an entanglement <https://en.wikipedia.org/wiki/Quantum_entanglement> between the system and heat bath (environment). As such, since the system is entangled with its environment in some unknown way, a description of the system by itself cannot be made without also referring to the environment (i.e. without also describing the state of the environment).
Notice that this doesn't explain how one gets to a single result. Brent -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
