> Il 12 luglio 2018 alle 3.57 [email protected] ha scritto: > > > > On Tuesday, July 10, 2018 at 11:23:55 PM UTC-6, scerir wrote: > > > > > > > > > > > Il 11 luglio 2018 alle 0.01 [email protected] ha > > scritto: > > > > > > > > > > > > On Monday, July 9, 2018 at 11:55:45 PM UTC-6, scerir wrote: > > > > > > > > > > > > > > > > > > > > > > > Il 9 luglio 2018 alle 22.46 > > > > [email protected] ha scritto: > > > > > > > > > > > > > > > > > > > > On Saturday, July 7, 2018 at 4:48:51 PM UTC-6, > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Saturday, July 7, 2018 at 12:19:23 PM > > > > > > UTC-6, [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Friday, July 6, 2018 at 1:56:12 PM > > > > > > > UTC-6, [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Friday, July 6, 2018 at > > > > > > > > 1:22:03 PM UTC-6, Brent wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On 7/6/2018 11:44 AM, > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Thursday, July > > > > > > > > > > 5, 2018 at 5:14:34 PM UTC-6, Brent wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On 7/5/2018 > > > > > > > > > > > 3:55 PM, [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On > > > > > > > > > > > > Thursday, July 5, 2018 at 2:03:46 PM UTC-6, Brent wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On 7/5/2018 11:27 AM, [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Wednesday, July 4, 2018 at 10:57:06 AM > > > > > > > > > > > > > > UTC-6, Brent wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On 7/4/2018 1:57 AM, 'scerir' via > > > > > > > > > > > > > > > Everything List wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > No. I am asserting that > > > > > > > > > > > > > > > > > the INTERPRETATION of the superposition of > > > > > > > > > > > > > > > > > states is wrong. Although I have asked > > > > > > > > > > > > > > > > > several times, no one here seems able to > > > > > > > > > > > > > > > > > offer a plausible justification for > > > > > > > > > > > > > > > > > interpreting that a system in a superposition > > > > > > > > > > > > > > > > > of states, is physically in all states of the > > > > > > > > > > > > > > > > > superposition SIMULTANEOUSLY before the > > > > > > > > > > > > > > > > > system is measured. If we go back to those > > > > > > > > > > > > > > > > > little pointing things, you will see there > > > > > > > > > > > > > > > > > exists an infinite uncountable set of basis > > > > > > > > > > > > > > > > > vectors for any vector in that linear vector > > > > > > > > > > > > > > > > > space. For quantum systems, there is no > > > > > > > > > > > > > > > > > unique basis, and in many cases also > > > > > > > > > > > > > > > > > infinitely many bases, So IMO, the > > > > > > > > > > > > > > > > > interpretation is not justified. AG > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ***SIMULTANEOUSLY*** was used > > > > > > > > > > > > > > > > by EPR in their paper, but that did not have > > > > > > > > > > > > > > > > much meaning (operationally, physically). > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Can we say that the observable, > > > > > > > > > > > > > > > > in a superposition state, has a ***DEFINITE*** > > > > > > > > > > > > > > > > value between two measurements? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > No - in general - we cannot say > > > > > > > > > > > > > > > > that. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > It's in some definite state. But it may > > > > > > > > > > > > > > > > be a state for which we have no measurement > > > > > > > > > > > > > > > > operator or don't intend to measure; so we say > > > > > > > > > > > > > > > > it is in a superposition, meaning a > > > > > > > > > > > > > > > > superposition of the eigenstates we're going to > > > > > > > > > > > > > > > > measure. So it does not have one of the > > > > > > > > > > > > > > > > eigenvalues of our measurement. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Brent > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > So for the radioactive source, the superposed > > > > > > > > > > > > > > state, Decayed + Undecayed, does NOT imply the > > > > > > > > > > > > > > system is in both states simultaneously? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > No, it is in a state that > > > > > > > > > > > > > > consists of Decayed+Undecayed. So in a sense it is > > > > > > > > > > > > > > in both simulatnaeously. If you are sailing a > > > > > > > > > > > > > > heading of 45deg you are on a definite heading. > > > > > > > > > > > > > > But you are simultaneously traveling North and > > > > > > > > > > > > > > East. And if someone was watching you with a radar > > > > > > > > > > > > > > that could only output "moving north" or "moving > > > > > > > > > > > > > > east" it would oscillate between the two and you > > > > > > > > > > > > > > might call that a superposition of north and east > > > > > > > > > > > > > > motion. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Brent > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > I see. > > > > > > > > > > > > But as I have pointed out, there are uncountably many > > > > > > > > > > > > sets of basis vectors that result in the same vector > > > > > > > > > > > > along the 45 deg direction. Thus, it makes no sense to > > > > > > > > > > > > single out a particular basis and claim it is > > > > > > > > > > > > simultaneously in both. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > That's where you're wrong. It makes perfect sense if > > > > > > > > > > > > that's the only basis you can measure in. That's why I > > > > > > > > > > > > gave the hypothetical example of a radar that could > > > > > > > > > > > > only report motion as northward or eastward. In some > > > > > > > > > > > > cases, like decayed our not-decayed, we don't have > > > > > > > > > > > > instruments to measure the superposition state. In > > > > > > > > > > > > other cases like sliver atom spin we can measure > > > > > > > > > > > > up/down or left/right or along any other axis. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ISTM, this is the cause of many of the apparent > > > > > > > > > > > paradoxes in QM such as Schroedinger's cat, or a > > > > > > > > > > > radioactive source which is decayed and undecayed > > > > > > > > > > > simultaneously. I have no objection using such a state to > > > > > > > > > > > do a calculation, but I think it's an error to further > > > > > > > > > > > interpret a superposition in terms of simultaneity of > > > > > > > > > > > component states. What say you? AG > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > I > > > > > > > > > > > > say use what's convenient for calculation. Don't > > > > > > > > > > > > imagine your calculation is the reality. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > But the consensus, > > > > > > > > > > perhaps unstated or subliminally, is that the superposition > > > > > > > > > > is imagined as reality, which leads to cats and radioactive > > > > > > > > > > sources being (respectively) alive and dead, and decayed > > > > > > > > > > and undecayed, simultaneously. Isn't this what Schroedinger > > > > > > > > > > was arguing against? I have rarely, if ever, seen it argued > > > > > > > > > > NOT to interpret a superposition as reality as a proposed > > > > > > > > > > solution to these apparent paradoxes. AG > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > You just go around and > > > > > > > > > > around. You never put together the explanations you get. > > > > > > > > > > Decoherence shows that, in the presence of an environment, > > > > > > > > > > the wave function FAPP collapses into orthogonal > > > > > > > > > > quasi-classical states in fractions of a nano-second. > > > > > > > > > > That's why the Schroedinger cat story doesn't show what > > > > > > > > > > Schroedinger thought it did. BUT there are experiments, > > > > > > > > > > like silver atoms thru and SG in which superpositions of > > > > > > > > > > left+right persist, they are up polarizations for example; > > > > > > > > > > and we know they exist because we can prepare up states and > > > > > > > > > > then measure them left/right or measure them up/down. The > > > > > > > > > > latter, up/down measurement, would always yield "up" > > > > > > > > > > showing they were in an up eigenstate, even though they > > > > > > > > > > were also in a left+right superposition. But there are > > > > > > > > > > other cases where we can't measure the eigenstate (e.g. > > > > > > > > > > neutrino family) so we always describe them as being in a > > > > > > > > > > superposition because the eigenstate is operationally > > > > > > > > > > unmeasurable and we can't prepare them in an eigenstate. > > > > > > > > > > > > > > > > > > Brent > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > You also go round and round > > > > > > > > without answering a key question about decoherence theory. You > > > > > > > > refer to the infinitesimally short decoherence time of, say, > > > > > > > > the apparatus, but ISTM it has already decohered way before it > > > > > > > > is employed in any experiment. What then is the reasoning for > > > > > > > > including the apparatus in the superposition for the entire > > > > > > > > system, and claiming this wf represents the total system before > > > > > > > > any environmental interaction? BTW, what is a right + left > > > > > > > > superposition in SG measurement, and how is it relevant to this > > > > > > > > discussion? TIA, AG > > > > > > > > > > > > > > > > (My computer is being repaired, > > > > > > > > so I have limited library time for possibly a week or more. > > > > > > > > This means I will have to study some of your examples later > > > > > > > > before possibly responding.) > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Thinking about this some more, I > > > > > > > agree that if one measures in a particular basis, it is natural > > > > > > > to express the wf of the system in a superposition of this basis. > > > > > > > However, where I disagree with your analysis is that one doesn't > > > > > > > need decoherence theory to resolve Schroedinger's apparent cat > > > > > > > paradox. This is because regardless of the natural basis used, > > > > > > > there is nothing in QM to allow, or compel us to interpret the > > > > > > > superposition as meaning the system is simultaneously in all > > > > > > > component states (which interpretation seems to produce an > > > > > > > alleged paradox). Moreover, although we cannot measure in other > > > > > > > bases, the wf can nevertheless be expressed in other bases, and > > > > > > > sometimes the set of bases is uncountable, again casting doubt on > > > > > > > the legitimacy of interpreting the superposition in terms of > > > > > > > simultaneity of component states. Do you agree or disagree? > > > > > > > > > > > > > > Also, when doing an SG spin > > > > > > > measurement, I don't see that right-left is well defined for a > > > > > > > well-defined Up / Dn measurement. I also don't see why the system > > > > > > > is assumed to be in a superposition of right + left, or why it > > > > > > > persists after the measurement, or in what way these facts -- if > > > > > > > they are facts -- is in any way enlightening. I would appreciate > > > > > > > your comments on these issues. > > > > > > > > > > > > > > TIA, AG > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > From Wiki; > > > > > > https://en.wikipedia.org/wiki/Quantum_superposition > > > > > > https://en.wikipedia.org/wiki/Quantum_superposition > > > > > > > > > > > > > > > > > > The principle of quantum superposition > > > > > > states that if a physical system may be in one of many > > > > > > configurations—arrangements of particles or fields—then the most > > > > > > general state is a combination of all of these possibilities, where > > > > > > the amount in each configuration is specified by a complex number > > > > > > https://en.wikipedia.org/wiki/Complex_number . > > > > > > > > > > > > For example, if there are two > > > > > > configurations labelled by 0 and 1, the most general state would be > > > > > > > > > > > > > > > > > > > > > > A|Up> + B|Dn> > > > > > > > > > > > > > > > > > > > > > > > > > > > where the coefficients A and B are complex > > > > > > numbers describing how much goes into each configuration. > > > > > > > > > > > > > > > > > > The principle was described by Paul Dirac > > > > > > https://en.wikipedia.org/wiki/Paul_Dirac as follows: > > > > > > > > > > > > > > > > > > > > > > > > > > The general principle of > > > > > > > superposition of quantum mechanics applies to the states [that > > > > > > > are theoretically possible without mutual interference or > > > > > > > contradiction] ... of any one dynamical system. It requires us to > > > > > > > assume that between these states there exist peculiar > > > > > > > relationships such that whenever the system is definitely in one > > > > > > > state we can consider it as being partly in each of two or more > > > > > > > other states. The original state must be regarded as the result > > > > > > > of a kind of superposition of the two or more new states, in a > > > > > > > way that cannot be conceived on classical ideas. Any state may be > > > > > > > considered as the result of a superposition of two or more other > > > > > > > states, and indeed in an infinite number of ways. Conversely any > > > > > > > two or more states may be superposed to give a new state... > > > > > > > (underlining my emphasis) > > > > > > > > > > > > > > > > > > > > > > > > > > IMO, he's mistaken. There's no need for the > > > > > > underlined assumption. If anyone here disagrees, please offer your > > > > > > *argument*. TIA, AG > > > > > > > > > > > > > > > > > > > > > > Cat got your tongue Brent? Bruce out to lunch? No > > > > > genuine seekers of truth here? What's the rationale for Dirac's > > > > > claim? I am all ears. AG > > > > > > > > > > > > > > > > > > "The non-classical nature of the superposition process > > > > is brought out clearly if we consider the superposition of two states, > > > > A and B, such that there exists an observation which, when made on the > > > > system in state A, is certain to lead to one particular result, a say, > > > > and when made on the system in state B is certain to lead to some > > > > different result, b say. What will be the result of the observation > > > > when made on the system in the superposed state? The answer is that the > > > > result will be sometimes a and sometimes b, according to a probability > > > > law depending on the relative weights of A and B in the superposition > > > > process. It will never be different from both a and b. The intermediate > > > > character of the state formed by superposition thus expresses itself > > > > through the probability of a particular result for an observation being > > > > intermediate between the corresponding probabilities for the original > > > > states, not through the result itself being intermediate between the > > > > corresponding results for the original states. (PAM Dirac, The > > > > Principles ......, second edition, 1947, page 12 ). > > > > > > > > > > > > > > IIRC, the above quote is also in the Wiki article. It's not a > > > coherent argument; not even an argument but an ASSERTION. Let's raise the > > > level of discourse. It says we always get a or b, no intermediate result > > > when the system is in a superposition of states A and B. Nothing new > > > here. Key question: why does this imply the system is in states A and B > > > SIMULTANEOUSLY before the measurement? AG > > > > > > > > > > Let us imagine the system is in state A or in state B before > > measurement. Would that be consistent with outcomes of experiments? > > > > > > I'm not exactly clear what Dirac means by states A and B. I think he > means the Up/Dn states of a spin measurement. Generally, If A and B are > eigenstates of the operator whose observable is being measured, the system > will remain in those eigenstates after measurement. OTOH, if A or B are > superpositions of other states, the system will be some eigenstate after the > measurement, possibly A or B if they are eigenstates of the operator being > measured. AG >
Somenthing useful maybe here: https://www.dropbox.com/s/nkly114dpabfy1t/quantum.pdf > > > > > > > > > > Let us imagine the state of system is a mixture of A and B. Would > > that be consistent with outcomes of experiments? > > > > > > A mixture isn't a superposition, so your question doesn't seem relevant > to my issue here; namely, the proper interpretation of a superposition of > states. AG > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Same for cat, Alive + > > > > > > > > > > > > > Dead? Same for ( (Undecayed, Alive) + (Decayed, > > > > > > > > > > > > > Dead) ) for Schroedinger's composite system? If > > > > > > > > > > > > > that's the case, why would anyone think these states > > > > > > > > > > > > > are in any way paradoxical or contradictory? AG > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > > > > > > > > > > > > > > > > > > > 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 > > > > > > > > > > > > > > https://groups.google.com/group/everything-list . > > > > > > > > > > > > > > > > > > > > > > > > > > > > For more options, visit > > > > > > > > > > > > > > https://groups.google.com/d/optout > > > > > > > > > > > > > > https://groups.google.com/d/optout . > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > > > 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 > > > > > > > > > > > > https://groups.google.com/group/everything-list . > > > > > > > > > > > > For > > > > > > > > > > > > more options, visit https://groups.google.com/d/optout > > > > > > > > > > > > https://groups.google.com/d/optout . > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > 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 > > > > > > > > > > https://groups.google.com/group/everything-list . > > > > > > > > > > For more options, > > > > > > > > > > visit https://groups.google.com/d/optout > > > > > > > > > > https://groups.google.com/d/optout . > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > 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 > > > > > https://groups.google.com/group/everything-list . > > > > > For more options, visit > > > > > https://groups.google.com/d/optout https://groups.google.com/d/optout > > > > > . > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > 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 > > > https://groups.google.com/group/everything-list . > > > For more options, visit https://groups.google.com/d/optout > > > https://groups.google.com/d/optout . > > > > > > > > > > > > > > -- > 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] > mailto:[email protected] . > To post to this group, send email to [email protected] > mailto:[email protected] . > Visit this group at https://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- 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.
