On Tuesday, December 5, 2017 at 7:57:57 AM UTC, [email protected] wrote: > > > > On Tuesday, December 5, 2017 at 5:32:22 AM UTC, [email protected] wrote: >> >> >> >> On Tuesday, December 5, 2017 at 3:59:19 AM UTC, [email protected] >> wrote: >>> >>> >>> >>> On Tuesday, December 5, 2017 at 12:50:54 AM UTC, Bruce wrote: >>>> >>>> On 5/12/2017 11:38 am, [email protected] wrote: >>>> >>>> On Tuesday, December 5, 2017 at 12:26:58 AM UTC, Bruce wrote: >>>>> >>>>> On 5/12/2017 3:15 am, Bruno Marchal wrote: >>>>> > On 01 Dec 2017, at 01:49, Bruce Kellett wrote: >>>>> >> On 1/12/2017 8:57 am, Bruce Kellett wrote: >>>>> >>> On 1/12/2017 4:21 am, Bruno Marchal wrote: >>>>> >>>> On 29 Nov 2017, at 23:16, Bruce Kellett wrote: >>>>> >>>> On 30/11/2017 2:24 am, Bruno Marchal wrote: >>>>> >>>>>> On 29 Nov 2017, at 04:59, Bruce Kellett wrote: >>>>> >>>>>> >>>>> >>>>>>> I would suggest that there is no such world. Whether a coin >>>>> >>>>>>> comes up head or tails on a simple toss is not a quantum >>>>> event; >>>>> >>>>>>> it is determined by quite classical laws of physics governing >>>>> >>>>>>> initial conditions, air currents and the like. >>>>> >>>>>> >>>>> >>>>>> It depends. If you shake the coin long enough, the quantum >>>>> >>>>>> uncertainties can add up to the point that the toss is a >>>>> quantum >>>>> >>>>>> event. With some student we have evaluate this quantitavely (a >>>>> >>>>>> long time ago) and get that if was enough to shake the coin >>>>> less >>>>> >>>>>> than a minute, but more than few seconds ... (Nothing >>>>> rigorous). >>>>> >>>>> >>>>> >>>>> That is a misunderstanding of quantum randomness. For the >>>>> outcome >>>>> >>>>> of a coin toss to be determined by quantum randomness, we would >>>>> >>>>> have to have a single quantum event where the outcome was >>>>> >>>>> amplified by decoherence so that it was directly entangled with >>>>> >>>>> the way the coin landed. Schematically: >>>>> >>>>> >>>>> >>>>> |quantum event>|coin> = (|outcome A> + |outcome B>)|coin> >>>>> >>>>> = (|outcome A>|coin heads> + |outcome B>|coin tails>) >>>>> >>>> >>>>> >>>> The coin is quantum. >>>>> >>> >>>>> >>> The coin is classical, consisting of something of the order of >>>>> 10^22 >>>>> >>> atoms. Indeterminacy in position as given by the Heisenberg >>>>> >>> Uncertainty Principle, is undetectably small. >>>>> >> >>>>> >> I think it is worth while to put some (approximate) numbers around >>>>> >> this. The reduced Planck constant, h-bar, is approximately 10^{-27} >>>>> >> g.cm^2/s. The Uncertainty Principle is >>>>> >> >>>>> >> delta(x)*delta(p) >= h-bar/2. >>>>> >> >>>>> >> For a coin weighing approximately 10 g and moving at 1 cm/s, the >>>>> >> momentum is mv = 10 g.cm/s. Taking the momentum uncertainty to be >>>>> of >>>>> >> this order, the uncertainty in position, delta(x) is of the order >>>>> of >>>>> >> 10^{-28} cm. A typical atom has a diameter of about 10^{-8} cm, so >>>>> >> the uncertainty in position is approximately 20 orders of magnitude >>>>> >> less than the atomic diameter. >>>>> > >>>>> > I think that is enough to get the macroscopic superposition, as, >>>>> like >>>>> > I explained, you have to take into account not just the quantum >>>>> > indeterminacy, + the classical chaos. You might need to shake for >>>>> some >>>>> > minutes. >>>>> >>>>> You could shake for longer than the age of the universe and you will >>>>> still not convert quantum uncertainties and classical thermal motions >>>>> into a macroscopic superposition. Do you know nothing about coherence? >>>>> And the fact that coherent phases between the components are what >>>>> separates a superposition from a mixture? >>>> >>>> >>>> Are the phase angles of components of a superposition identical? If so, >>>> is this the definition of coherence? TIA, AG >>>> >>>> >>>> No, why should they be equal. You really do have to learn some basic >>>> quantum mechanics, Alan, and stop bothering the list with such questions. >>>> >>>> Bruce >>>> >>> >>> Was I bothering the list when I started this thread, and others? I >>> recall from class the answer is NO, because the probabilities are >>> unaffected when taking complex conjugates (ignoring interference), but >>> other comments on Avoid2 for example, when I was a member, indicated >>> otherwise. Also, the poster here you're replying to seemed not to >>> understand as well. Next time take THAT into account. AG >>> >> >> I took a few graduate courses in QM at major US universities and do not >> recall any discussion about coherent states of superposition when solving >> the SWE or Dirac's equation. Maybe the universities in Australia do a >> better job. I suggest you be more tolerant in the future, notwithstanding >> the burden that your knowledge of these subjects places on your karma. And >> keep in mind that I am responsible the interactions you are now enjoying. >> That should count for something. Don't ya think? FWIW, I initially left >> Avoid2 because of the abuse. AG >> > > All I can recall about the phase factor in QM is that it's arbitrary, > insofar as whatever value is chosen doesn't effect the result of Born's > rule. I suppose that makes me a moron from the pov of an expert. The > implication was, for me, that it can't be explicitly calculated. Hence, my > question. AG >
To wrap it up, if the phase factor is arbitrary, which is what my professor indicated, it's puzzling how a sum of solutions as a superposition could have fixed relations among those factors to yield a coherent wf. I may not be the brightest bulb in the room when it comes to QM, but a dumb question it is NOT. AG > > >>>> Random quantum uncertainties >>>>> and thermal motions are not coherent, so cannot form superpositions. >>>>> >>>> -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
