I said that Lorentz boosts don’t perserve volume elements, what was I thinking about?!! Of course they do. Perhaps I was thinking about line elements? Now tranlational invariance of state normalization is not gauraneted in curved space-times like the Schwardchild metric, or other solutions where the speed of light varies on a cosmic scale.

Perhaps what I was thinking about was the Dirac solution for the electron. The inner product of wave four vectors will is not invariant with respect to Lorentz boosts. So two states that are orthongonal in one reference frame may not be in a moving reference frame.

Sorry for the idiocy, I must remember to think before I type.

Best regards,

I do think we need to broaden the interpretation from the pure idea that things only happen when we observe them happening. This is disconcerteningly self centred

Replacing “observation” with “interaction” is at the heart of what Rovelli and also the Everettian’s are trying to do. The problem is that we are forced to adopt a very odd ontology in both these attempts.

For me, the main issue is the “reality problem”. If we deny reality both to quantum states and to the usual notion of hidden variables then only the probability rule is left to connect the quantum formalism to things that really happen in the universe. It would be nice to think that science can describe what is really going on in the world in the absence of measuring devices, observers, etc., but I don’t think any interpretation of QM gives a compelling answer to this yet.

I’d like to forward a motion to remove the word ‘observation’ from all interpretations of QM and replace it with the word ‘interaction’. This would make QM processes a bit more similar to Markov processes.

Do the yeas have it? Motion carried?

With regard to quant-ph/0506228 because Lorentz boosts don’t perserve volume elements (go ahead take that determinant, make my day) I would be cautious of relativistic theories that do not include changes in the normalization and orthoganality of QM states. There is a trick to get around this, but my lips are sealed out of fear of being called a crack pot, cracked pot, or just a general crack smoker.

I think there is a formalism out there, waiting to be discovered, that makes much more sense in a relativistic context than any way QM has been written down before. Discovering such a thing could be the key to understanding QM for the universe as a whole. That’s just my opinion though, and I am happy to let the quantum gravity experts worry about these problems until I can come up with a better idea.

Are we expected to accept that making one single measurement defines the state throughout all space-time? I hope not, this is just determenism in sheeps clothing.

So the battle rages thus: Perhaps wave functions are only defined on single light cone slices through space-time. Different measurements can intersect along two dimensional surfaces, but this is okay because measure theory only requires that the states be defined almost everywhere, which means we can leave wave functions undefined at the intersection of light cones. However this means that we can only every make a countably infinite number of observations of the universe, not a continum of observations.

As for defining an evolution operator, lets not even go there.