Quantum theory of measurement

Hi all, I'm writing something that touches on issues of quantum measurement (though the main theme is something different), and I want to be sure I'm not saying anything wrong about this very tricky subject. So I'm going to pose some thought-experiments to the physics experts on this list. I

RE: Quantum theory of measurement

Hi, Oops, I gave the wrong link I said > Specifically, I'll refer to the quantum eraser thought experiment > summarized at > > http://grad.physics.sunysb.edu/~amarch/ but I meant http://www.dhushara.com/book/quantcos/qnonloc/eraser.htm Anyway, the essential idea of the two experiments is

Re: Quantum theory of measurement

Ben Goertzel writes about: > http://grad.physics.sunysb.edu/~amarch/ > > The questions I have regard the replacement of the Coincidence Counter (from > here on: CC) in the above experiment with a more complicated apparatus. > > What if we replace the CC with one of the following: > > 1) a carefull

RE: Quantum theory of measurement

Hal, > > What will the outcome be in these experiments? > > It won't make any difference, because the CC is not used in the way you > imagine. It doesn't have to produce a record and it doesn't have to erase > any records. OK, mea culpa, maybe I misunderstood the apparatus and it was not the CC

RE: Quantum theory of measurement

What if instead of "throwing out" the information you shoot it into a black hole? Then presumably the information is really gone so the result should be as if the information were "quantum erased"?? Unless there are white holes of course!! ;-) > > Yes but we are choosing which half to throw ou

RE: Quantum theory of measurement

Ben Goertzel writes: > Hal, > > It won't make any difference, because the CC is not used in the way you > > imagine. It doesn't have to produce a record and it doesn't have to erase > > any records. > > OK, mea culpa, maybe I misunderstood the apparatus and it was not the CC > that records > thing

Re: Quantum theory of measurement

Hal gives the correct explanation of what's going on. In general, all you have to do to analyze the problem is to consider all contributions to a particular state and add up the amplitudes. The absolute value squared of the amplitude gives the probability, which may or may not contain an interfere

RE: Quantum theory of measurement

Hal Finney wrote: Ben Goertzel writes: > Hal, > > It won't make any difference, because the CC is not used in the way you > > imagine. It doesn't have to produce a record and it doesn't have to erase > > any records. > > OK, mea culpa, maybe I misunderstood the apparatus and it was not the

Re: Quantum theory of measurement

From: "Ben Goertzel" > [...] but still the records > could be kept somewhere, > and one can ask what would happen > if the records were kept somewhere else [...] Not sure, but the quote below - about the information 'in principle' - might be helpful. "The superposition of amplitudes is only va

Re: Quantum theory of measurement

scerir wrote: From: "Ben Goertzel" > [...] but still the records > could be kept somewhere, > and one can ask what would happen > if the records were kept somewhere else [...] Not sure, but the quote below - about the information 'in principle' - might be helpful. "The superposition of amplit

RE: Quantum theory of measurement

Thanks very much Jesse! You answered the question I *would have* asked had I rememberd my quantum physics better ;-) I think your answer is related to a paradox a friend mentioned to me. The paradox is as follows: "One does the EPR thing of creating two particles with opposite spin. Send one f

RE: Quantum theory of measurement

Ben Goertzel wrote: Thanks very much Jesse! You answered the question I *would have* asked had I rememberd my quantum physics better ;-) I think your answer is related to a paradox a friend mentioned to me. The paradox is as follows: "One does the EPR thing of creating two particles with o

RE: Quantum theory of measurement

Ben Goertzel wrote: My own understanding is that whether Fred, a pigeon or a printer is involved in the experiment should be basically irrelevant. That is, I don't think "registration in consciousness" (whatever that means) is the important thing, but rather registration in the sense of "sta

RE: Quantum theory of measurement

Now that you are experts on this, try your hand on this FTL signalling device, . The author, Daniel Badagnani, is apparently a genuine physicist, . Hal Finney

Re: Quantum theory of measurement

Hi Ben, Could it be that black holes do not "destroy" information but merely randomize it, ala decoherence? For a hint see: http://www.arxiv.org/abs/quant-ph/0410172 Onward! Stephen - Original Message - From: "Ben Goertzel" <[EMAIL PROTECTED]> To: Sent: Wednesday, October 12,

Re: Quantum theory of measurement

From: "Ben Goertzel" > The paradox is as follows: > "One does the EPR thing of creating two particles > with opposite spin. [...] More or less, it is the experiment by Birgit Dopfer (pdf on this page, unfortunately just in German) http://www.quantum.univie.ac.at/publications/thesis/