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 > >> 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.
