Recent content by andresB

You can take it as a postulate, and together with the algebra of the space-time transformations you can derive Quantum mechanics. See for example the book by Ballentine.

I...work in physics. Journals do charge for papers, but most authors nowadays publish preprints. Also, most people are willing to share a copy of their work if you ask them nicely. Worst case scenario, I have to ask around with friends and online groups if anyone can download the paper for me...

Well, the same way I'm doing right now. I use exactly zero resources from the university, not even a library to access technical publications. Except for some obscure russian articles from the 70s, I think I've never had an issue finding the paper I want to read.

Well, of course. That is why I said that I reluctantly use an institutional affiliation so it doesn't get rejected for that only. However, my statement was different; I said that the quality of my work would be the same if I were to work in a bakery. And I stand by it. Much harder to publish...

do please elaborate

Well, then yes. I considered trying the "independent scholar" approach to publishing, but I don't think it works for physics https://www.physicsforums.com/threads/viability-of-publishing-as-an-independent-researcher.1006876/

I most definitely don't. I do all my work at home, on my PC, with no resources from anywhere else. The university I work for doesn't even know that I publish things.

I suppose that depends on what "independent researcher" means. While I teach some introductory courses at a University, my research is entirely my own, with no support from any source. If I were to work at a bakery instead, the quality of my published research would have been the same.

I don't think is that simple since self-adjointness is a much more tricky concept in the infinite-diemsional case. For example, the eigenstates of the hydrogen atom separates as ##\psi=\psi_{CM}\psi_{Rel}## for the center of mass and the relative motion of the proton-electron. ##\psi_{CM}## is...

Ok, got it. But what about wavefunctions? For example, given a wavefunction ##\psi(x,y)## that can be separated by change of variables ##X =X(x,y)## and ##Y =Y(x,y)## so that $$\psi(X,Y)=\psi_{1}(X)\psi_{2}(Y),$$ can we say that this imply that there exist self-adjoint operators with...

I was reading a review on single-particle entanglement https://onlinelibrary.wiley.com/doi/10.1002/qute.202000014 and the author says this It's probably a simple/well known result, but I'm not seeing any trivial proof at the moment. Moreover, I'm interested in the general case of arbitrary...

Well, yes. I'm interested in the energy eigenvalue problem with its its boundary conditions using the momentum SE.

I understand what you say, but it seems that doesn't create any problem in momentum space since not only we can get the correct energy levels but we can also get the stationary states in configuration space by a Fuorier transform.

So, the mathematics in momentum space seems to work. Yet, I'm still puzzled by the boundary conditions in momentum space. I don't see any logic, from the probabilistic point of view, that allows me to get those boundary conditions without using a Fourier transform.

@vanhees71 I understand what you say about self-adjoint operators, but it seems that no problem arises when solving these system in momentum space.