On Fri, Oct 16, 2020 at 3:38 PM Russell Standish <[email protected]> wrote:
> On Fri, Oct 16, 2020 at 10:07:32AM +1100, Bruce Kellett wrote: > > > > It is refuted by the idea of unitary evolution in QM. Unitary evolution > means > > that everything is reversible, If new microstates are created as the > universe > > expands, then this expansion cannot be reversed: the creation of such > > microstates gives an absolute arrow of time. This is generally rejected, > > because physicists tend to believe in unitary dynamics. If dynamics are > not > > unitary, then the universe is not governed by the Schrodinger equation, > and > > arguments for the multiverse collapse. > > I'm not sure the last point follows, perhaps you can expand on it. But > it is an interesting argument that the Layzer style "increase in > microstates" > should be enough to prevent a Hawking style "wavefunction of the > universe". > I was talking about the Everett-style quantum many worlds. Other types of multiverse (such as the existence of other cosmological Hubble volumes) are not necessarily affected. Hawking's "wave function of the universe" is a definite casualty if unitary evolution is denied. > Could the ideas be made compatible by have the number of accessible > microstates increasing over time, due to the expansion of the > universe, but that the total number remains constant, or is even > infinite? Or does that place us right back at the original problem of > having a low entropy initial state. > I don't really understand this. An infinite number of microstates makes little sense in standard thermodynamics. Bruce -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLR0tOVHvtca-rtPUPV7n6DOD%3DqqFMjicoTduC2DQLEXVg%40mail.gmail.com.
