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 >>> 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.
