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rodsika
#72
Apr23-11, 05:58 PM
P: 275
Quote Quote by Rap View Post
Please explain "shielded from the geometry of spacetime". I don't understand that. By explain, I mean, describe a process by which an object can be shielded from the geometry of spacetime, or describe an experimental procedure to determine whether an object is shielded from the geometry of spacetime.
Ignore the above for now while I ask the relativity forum whether spacetime geometry is produced by matter or it is there even without matter.

I've been reading an interesting thread in the archive called "Does Schrodinger's Cat Paradox Suck?" where you participated and exchanged ideas with someone called Ken G.

Ken G. wrote:

The state of the cat must be viewed as a substate of the whole system, it is a projection that does not obey the Schroedinger equation. That equation applies to the closed system on the Hilbert space, not open substates that are projections onto subspaces of the Hilbert space. The subspaces do not preserve the postulates of quantum mechanics (in particular, they evolve into mixed states under decoherence, not superposition states), and this is the source of a lot of misunderstanding about the cat paradox.

Indeed, that is perhaps the key difference between a micro system and a macro system, it is the meaning of the Heisenberg divide: a micro system, as a substate, can recover its status as a pure state by measuring it and isolating it-- even though it remains a substate of something larger, it can be treated as a pure state going forward (and exhibit interference and so on). But a macro system, once evolved into a mixed state via external interactions, can never recover its pure state status, it is forever a substate of something larger, and will never exhibit interference. It is just wrong to say that baseballs don't give two-slit patterns because their wavelengths are too small, they are simply not in pure states period.
You believe that a cat can never be in pure state by principle? But if one used the Heisenberg Interpretation where there is actual ontology. Can the cat exist as pure state? In Copenhagen, maybe it's not possible because they believe the wave function as just calculational tool. Without tracking the cat body down to the atoms and particles. You don't know the wave function to enter into calculation. In this sense. One can't treat the cat as in pure state when completely isolated in 100% hypothetical isolation box. But in Heisenberg Interpretation where everything actually happens. Maybe we can say that the cat is in pure state even if we didn't measure or prepare it to be in pure state from the beginning?? Or is the analysis the same in both Copenhagen and Heisenberg version where the cat can never be in pure state because beside not able to prepare it in pure state, the cat complex body parts can never in principle be in pure state? (Jesse, if you are reading this, pls comment too as we have discussed at length about pure state, mixed state but you are using Copenhagen version. What happens if we use the Heisenberg version where everything *actually* happens (like superposition, collapse) as described).