Recent content by gentzen

I finished browsing Albert's "Quantum Mechanics and Experience" book, and studying its last chapter "8. Self-Measurement", where his "definiteness" operator D gets discussed (even so is neither called "definiteness" operator nor abbreviated with D). The discussion is in the typical style of...

iste is talking about Barandes' formalism. In your example, Barandes talks about the normal Hilbert space formalism of QM. This doesn't help with the unclear distinction between his (or Morbert's?) interpretation of QM and (Barandes' formulation of) the math of indivisible stochastic processes.

I guess, the biggest contribution of Barandes' "interpretation" is that it shows just how difficult it is to convincingly "disprove" an interpretation, or at least to nicely explain why it feels really unsatisfactory (in its current form). You might think that Copenhagen and Bohmian mechanics...

I remember that he recently switched to a new attack on BM: The local phase of the wavefunction is a gauge freedom, but the actual BM trajectories depend crucially on that local phase.

But Barandes attacks MWI as untenable, so this can't be an excuse for him. I would have to lookup the detailed reasons for Barandes' opposition to Bohmian mechanics. I guess he went with "BM is unable to handle relativistic QFT, and especially fundamentally unable to handle fermionic fields"...

Exactly, that is the impression I got.

Thanks for trying to drive this forward to closure. Your "more general version of your argument" nicely captures the reasons why However, this only convinces me that Coleman's argument is too weak, in the way he presented it. The concrete weak point is pointed out here: The problem is that...

For "my fixed version of" Demystifier's simplified scenario, L was defined as The "more mundane measurement operators" would just measure a single classical state. For example, an operator M_{iL,nR} could be defined via M_{iL,nR} |neutral_L, neutral_R⟩ = 0 M_{iL,nR} |ionized_L, neutral_R⟩ =...

Turns out L should be consistent with those more mundane measurement operators. They should be a simple refinement of L. (I have no opinion about D, because it feels complicated and hard to define to me.)

The observation is just the eigenvalue and its associated eigenspace. Even so there is a state after measurement, I don't always learn that state during measurement. If there were only one eigenvector corresponding to the measured eigenvalue, then I would learn the state after measurement. But...

Because he cares about the state of the cloud chamber, i.e. the state of the measurement apparatus. And if the possible dots constitue the measurement apparatus, then both "no dots" and "two dots" are possible results, and both have corresponding states.

No, I tried to guess what you might have in mind when you claimed: "I said it (quite strongly) leads to the opposite prediction, that we should not see a single straight line track." I didn't use any interpretation of quantum mechanics when I tried to follow Coleman's argument. I just looked at...

Good, but then I simply disagree with you on that point. I mean, as a proponent of the consistent histories interpretation, I wonder whether those strange measurement operators L and D will not be inconsistent with more mundane measurement operators just observing whether some specific...

Yeah, after my reply to Demystfier #48, I also became unsure. If his argument should be too weak to explain why we see a single straight line track, then I feel it should also be too weak to imply the opposite.

Not for Coleman. For him, the relevant Hilbert space is that of the dots. For Coleman, there are states ##|none\rangle## and ##|both\rangle##. And Coleman does not mean a superposition such as ##|up\rangle+|down\rangle## by this. If you want to convince me or martinbn that Coleman's argument...