Looking back, I find my initial statement not so bad as a summary. In this exchange I did not see any argument suggesting that Bohmian trajectories should be taken more seriously than a fairy tale. Inventing some idle wheels for a theory and claiming that these now make the theory more realistic is diametrically opposed to what I would call…[Read more]

Travis,
I just meant that any observation in BM requires the description of the whole measuring apparatus in BM terms. As I was told recently (arXiv:1408.1651), it is morally wrong to think otherwise, even if position is meaasured. Of course, BM seems to have a special relationship to position and I have seen the agreement of the…[Read more]

Dustin,
indeed I have no problem with fuzzy assumptions, if you are honest about them. I would also clearly not object to Bohmians using arguments from QM. It is a different thing though, when the claim is that from “exact” BM you can derive QM, when that derivation is full of decoherence assumptions about the measuring devices. You could say…[Read more]

Ok Travis, maybe we are getting somewhere.

For (1) I would just ask you to avoid terms like “directly observable”. Not even position is in BM, as you well know.

Does BM ever make “exactly” the right predictions? Surely not, because this depends on the additional assumptions. Actually, no theory ever makes “exact” predictions. You will realize…[Read more]

Dear Dustin,
on the note of your pre-previous post: I take back the word “pamphlet”. What I meant is the kind of paper that starts with declaring mainstream QM to be deluded, in contrast to “exact” and “clear” BM. What is the point of this self-congratulatory note? Shouldn’t clarity be the result of an investigation and left to the reader to…[Read more]

Dear Rainer (if I may),

it is not completely clear to me what SQM is. In the operational account of the theory (let’s call that OQM) the only requirement on a preparation process is that the preparing system is dynamically decoupled from the ES and from whatever measuring device you plan to use. Entanglement between preparing system and ES is…[Read more]

Dear Dustin, Aurelien and Travis,
I guess this workshop is coming to a close, so let me try to wrap up some.

Dustin: My “hostility” to BM is only that I am totally underwhelmed by it. Given that, I did put way too much energy into discussions like this in the last year or so (on this particular occasion on the explicit invitation by Travis),…[Read more]

Dear Bob,

I completely agree with the advice you give via the Wigner anecdote. If you want to understand a theory, start with the minimal examples. However, my impression is that Bohmians have given up on getting any physical sense out of few-particle examples.

I spent a good part of last summer on an exchange with Shelly Goldstein on a…[Read more]

Dear Jean,

so BM is “a real theory”? As opposed to what? I also find your use of the attribute “rational” pretty strange. I suppose you would describe yourself as a rationalist, and I do like your book with Sokal on his hoax. But I think you are just mistaken that rationality is tied to some kind of ontology (as in that silly slogan that…[Read more]

Dear Miroljub,
you might also ask in the same way why, if a hydrogen atom in the ground state is a static configuration (as in BM), a gas of such things does not behave like a gas of permanent (though random) dipoles but like a gas of neutral particles. The difference would indeed be massive, and I heard Berge Englert raising this question.…[Read more]

Hi Travis,
what I meant by “gravitationally and electrodynamically invisible” is just the undisputed fact that you should not take these particles as a source for the respective fields. In my statement that the “interaction is always with the wave function” replace “with” by “via”. Again I just meant the form of the equations. I admit that a…[Read more]

Dear Dustin and Travis,

so, according to Travis, I “have a number of simple factual misconceptions about how Bohm’s theory works and what it says.” I feel that I do understand fairly well how the theory works, but that is somehow at variance with what Bohmians like to say about it. Of course, the root for the whole disagreement is further d…[Read more]

Dear Miroljub, I don’t quite get your point. Of course, as a theoretical physicist I am all for explanations. That is my line of work. I just do not see BM providing any. The Bohmian line that QM does not explain anything, because it is not operating in terms of some “real factual situation of the universe” is based on a different idea of…[Read more]

Dear Max,

don’t expect too much. There will be nothing for teleportation, computation, no-cloning etc except a blanket “nostrification”, i.e., the claim that if QM can do it so can BM (because, allegedly, BM==>QM). But the analysis of trajectories will add nothing at all to the understanding of these structures, because, to begin with, it is…[Read more]

Dear Dustin,
so you do agree also that Bohmian trajectories are unobservable as a matter of principle. I think that does have some bearing on the issue of “empirical content”. In fact, I would say that this directly shows that Bohmian Mechanics has zero empirical content.

That is, if you take “empirical” as referring to some kind of…[Read more]