> 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? Let us imagine the state of system is a mixture of A and B. Would that be consistent with outcomes of experiments? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 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] > 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. 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