On Wednesday, August 22, 2018 at 2:19:43 PM UTC, Jason wrote: > > > > On Wed, Aug 22, 2018 at 2:06 AM <[email protected] <javascript:>> wrote: > >> >> >> On Tuesday, August 21, 2018 at 10:30:01 PM UTC, Jason wrote: >>> >>> >>> >>> On Tue, Aug 21, 2018 at 4:40 PM <[email protected]> wrote: >>> >>>> >>>> >>>> On Tuesday, August 21, 2018 at 8:02:52 PM UTC, Jason wrote: >>>>> >>>>> >>>>> >>>>> On Tue, Aug 21, 2018 at 2:20 PM <[email protected]> wrote: >>>>> >>>>>> >>>>>> >>>>>> On Tuesday, August 21, 2018 at 3:04:45 PM UTC, Jason wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Wed, Aug 15, 2018 at 1:44 PM <[email protected]> wrote: >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Wednesday, August 15, 2018 at 2:41:12 PM UTC, Jason wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Wednesday, August 15, 2018, <[email protected]> wrote: >>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Wednesday, August 15, 2018 at 11:49:04 AM UTC, Bruno Marchal >>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On 15 Aug 2018, at 12:36, [email protected] wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Wednesday, August 15, 2018 at 10:22:40 AM UTC, agrays...@ >>>>>>>>>>> gmail.com wrote: >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> On Wednesday, August 15, 2018 at 9:58:57 AM UTC, Bruno Marchal >>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> > On 14 Aug 2018, at 22:12, Brent Meeker <[email protected]> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>>> > On 8/14/2018 3:54 AM, Bruno Marchal wrote: >>>>>>>>>>>>> >> How do you explain interference fringes in the two slits? >>>>>>>>>>>>> How do you explain the different behaviour of u+d and a mixture >>>>>>>>>>>>> of u and d. >>>>>>>>>>>>> >> >>>>>>>>>>>>> >> If the wave is not real, how doe it interfere even when we >>>>>>>>>>>>> are not there? >>>>>>>>>>>>> > >>>>>>>>>>>>> > How does it interfere with itself unless it goes through >>>>>>>>>>>>> both slits in the same world...thus being non-local. >>>>>>>>>>>>> >>>>>>>>>>>>> The wave is a trans-world notion. You should better see it as >>>>>>>>>>>>> a wave of histories/worlds, than a wave in one world. I don’t >>>>>>>>>>>>> think “one >>>>>>>>>>>>> world” is well defined enough to make sense in both Everett and >>>>>>>>>>>>> Mechanism. >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> *If you start with the error tGhat all possible results of a >>>>>>>>>>>> measurement must be realized, you can't avoid many worlds. Then, >>>>>>>>>>>> if you >>>>>>>>>>>> fall in love with the implications of this error, you are firmly >>>>>>>>>>>> in woo-woo >>>>>>>>>>>> land with the prime directive of bringing as many as possible into >>>>>>>>>>>> this >>>>>>>>>>>> illusion / delusion. This is where we're at IMO. AG * >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> *Truthfully, I don't know why, when you do a slit experiment one >>>>>>>>>>> particle at a time, the result is quantum interference. It might be >>>>>>>>>>> because >>>>>>>>>>> particles move as waves and each particle goes through both slits. >>>>>>>>>>> In any >>>>>>>>>>> event, I don't see the MWI is a solution to this problem. It just >>>>>>>>>>> takes us >>>>>>>>>>> down a deeper rabbit hole. AG* >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Everything is in the formalism, as well exemplified by the two >>>>>>>>>>> slits. If you miss this, then consider the quantum algorithm by >>>>>>>>>>> Shor. >>>>>>>>>>> There, a “particle” is not just going through two slits, but >>>>>>>>>>> participate in >>>>>>>>>>> parallel, yet different computations, and we get an indirect >>>>>>>>>>> evidence by >>>>>>>>>>> the information we can extract from a quantum Fourier transform on >>>>>>>>>>> all >>>>>>>>>>> results obtained in the parallel branches. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> *No. It's all nonsense. AG * >>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>> No it's something you can already buy and use today: >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> https://techcrunch.com/2017/11/10/ibm-passes-major-milestone-with-20-and-50-qubit-quantum-computers-as-a-service/ >>>>>>>>> >>>>>>>>> Jason >>>>>>>>> >>>>>>>> >>>>>>>> *If you're referring to my critique of the standard quantum >>>>>>>> interpretation of the superposition of states -- that a system in a >>>>>>>> superposition is in ALL component states SIMULTANEOUSLY -- show me >>>>>>>> where >>>>>>>> that INTERPRETATION is used in quantum computers.* >>>>>>>> >>>>>>> >>>>>>> It's in the definition of a qubit: >>>>>>> https://en.wikipedia.org/wiki/Qubit >>>>>>> >>>>>> >>>>>> *But that's not nearly enough. You have to show where the assumption >>>>>> is applied. In the case of standard QM, the superposition is written as >>>>>> a >>>>>> sum of eigenstates, which are mutually orthogonal. So, as I pointed out >>>>>> exhaustively with no takers, the assumption isn't used in calculating >>>>>> probabilities. When you take the inner product of an eigenstate with the >>>>>> wf, all terms drop out except the eigenvalue whose probability you are >>>>>> calculating. Is the situation different with qubits*? AG >>>>>> >>>>> >>>>> >>>>> These superposed states either exist or they don't. Which is it in >>>>> your view? In my view they exist, because that is the only way to >>>>> explain >>>>> the computational power of a quantum computer. >>>>> >>>> >>>> *I am not doubting the existence of the superposed states; just their >>>> *interpretation* which is key to achieving the postulated speeds of >>>> quantum >>>> computers. See comment below. AG * >>>> >>>>> >>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>>> >>>>>>>> * I know it isn't used to calculate probabilities in quantum >>>>>>>> theory. It's a postulate which is NOT used, so by Occam Razor it >>>>>>>> should be >>>>>>>> eliminated. AG* >>>>>>>> >>>>>>> >>>>>>> >>>>>>> You can't calculate the final probabilities without assuming the >>>>>>> qubits enter the superposition of all possible states, >>>>>>> >>>>>> >>>>>> *See above. I am not questioning the existence and utility of the >>>>>> superposition itself, but the assumption that a system in a >>>>>> superposition >>>>>> is simultaneously in all component states of the superposition. AG* >>>>>> >>>>>> >>>>> >>>>> If I start a 200 qubit quantum computer at time = 0, and 100 >>>>> microseconds later it has produced a result that required going through >>>>> 2^200 = 1.6 x 10^60 = states (more states than is possible for 200 things >>>>> to go through in 100 microseconds even if they changed their state every >>>>> Plank time (5.39121 x 10^-44 seconds), then physically speaking it * >>>>> *must** have been simultaneous. I don't see any other way to explain >>>>> this result. How can 200 things explore 10^60 states in 10^-4 seconds, >>>>> when a Plank time is 5.39 x 10^-44 seconds? >>>>> >>>> >>>> >>>> *Impressive calculation to be sure, but is this a theoretical value >>>> based on the assumption I deny; or is it achieved by a working quantum >>>> computer? AG * >>>> >>>>> >>>>> >>> >>> There are working quantum computers with 72 qubits (I had to update this >>> from 50 after doing some searching). >>> >>> Nothing in the theory implies larger quantum computers can't be built, >>> it is only a problem of engineering. See this graph of recent progress: >>> >>> https://www.ibm.com/blogs/research/wp-content/uploads/2018/04/Quantum_Volume_benchmark.png >>> >>> Will you change your mind when a 200 qubit quantum computer is built? >>> From the trend of the graph it looks like we could get there by next year. >>> >>> >>> >>>> >>>>> >>>>>> which is why it becomes exponentially hard to predict what happens >>>>>>> with a larger number of qubits in a quantum computer. This is why >>>>>>> large >>>>>>> scale quantum computers must be built, we can't just simulate them with >>>>>>> regular computers because the number of states it is simultaneously in >>>>>>> quickly becomes enourmous: >>>>>>> >>>>>>> 1 qubit: 2 states >>>>>>> 5 qubits: 32 states (you can use this quantum computer for free on >>>>>>> the link I provided) >>>>>>> 10 qubits: 1024 states >>>>>>> 20 qubits: 1,048,576 states (you can pay to use this quantum >>>>>>> computer today >>>>>>> >>>>>> >>>>>> >>>>>>> ) >>>>>>> 30 qubits: 1,073,741,824 states >>>>>>> 50 qubits: 1,125,899,906,842,624 states (IBM recently built a >>>>>>> quantum computer with 50 qubits >>>>>>> <https://www.technologyreview.com/s/609451/ibm-raises-the-bar-with-a-50-qubit-quantum-computer/> >>>>>>> ) >>>>>>> 100 qubits: 1,267,650,600,228,229,401,496,703,205,376 states >>>>>>> 200 qubits: >>>>>>> 1,606,938,044,258,990,275,541,962,092,341,162,602,522,202,993,782,792,835,301,376 >>>>>>> >>>>>>> states >>>>>>> 1000 >>>>>>> qubits: >>>>>>> 10,715,086,071,862,673,209,484,250,490,600,018,105,614,048,117,055,336,074,437,503,883,703,510,511,249,361,224,931,983,788,156,958,581,275,946,729,175,531,468,251,871,452,856,923,140,435,984,577,574,698,574,803,934,567,774,824,230,985,421,074,605,062,371,141,877,954,182,153,046,474,983,581,941,267,398,767,559,165,543,946,077,062,914,571,196,477,686,542,167,660,429,831,652,624,386,837,205,668,069,376 >>>>>>> >>>>>>> states >>>>>>> >>>>>>> We know of nothing in principal that can accurately simulate the >>>>>>> behavior of a system of 1000 entangled atoms in a reasonable period of >>>>>>> time >>>>>>> besides a quantum computer. The reason is the number above (2^1000) is >>>>>>> so >>>>>>> large that ant attempt to simulate it will fail due to physical limits >>>>>>> of >>>>>>> time, energy, and space within this universe. So if the computational >>>>>>> capacity of this universe is insufficient to compute what this system >>>>>>> of >>>>>>> 1000 qubits will do, what in physics is known which has the >>>>>>> sufficiently >>>>>>> large state and computational capacity to perform such a calculation? >>>>>>> >>>>>>> Answer: the wave function >>>>>>> >>>>>>> At the current time, there is no other known answer nor any hint of >>>>>>> another theory that can explain the power of quantum computers. The >>>>>>> only >>>>>>> answer we have is that the wave function is something that is >>>>>>> physically >>>>>>> real. >>>>>>> >>>>>>> >>>>>>> >>>>>>>> >>>>>>>> *WRT the MWI, it's too tortured and extravagant to be in the >>>>>>>> ballpark of reality. AG* >>>>>>>> >>>>>>> >>>>>>> Do you have an alternate theory for how quantum computers can be in >>>>>>> so many states simultaneously? >>>>>>> >>>>>> >>>>>> *I am not convinced of the simultaneous claim. Where is it actually >>>>>> applied? It isn't in standard QM. AG* >>>>>> >>>>>>> >>>>>>> >>>>> I don't know that there is any definition of "standard QM". >>>>> >>>> >>>> *I just meant the Copenhagen postulates of QM. Earlier I reproduced >>>> Dirac's comment (from Wiki, "Superposition of States") concerning the >>>> usual >>>> interpretation of a superposed state, which I don't think is formally a >>>> postulate. Also, Schroedinger's thought experiment was specifically >>>> designed to deny it. A*G >>>> >>>> >>> >>> The postulate is #5 in this list: >>> http://vergil.chemistry.gatech.edu/notes/quantrev/node20.html >>> >> >> *It is NOT! Maybe English isn't your native language. You don't seem to >> have the vaguest idea concerning the content of my last comment.* >> > > Try not to be insulting on this list. We're both hear to learn, aren't we? > > You might think it is unrelated, but it is not. As the SWE evolves in > time, superpositions naturally arise. > > >> >> * The evolution of the wf via the SWE is UNRELATED to my claim about >> superposition! And it is NOT one of the stated postulates of QM! AG * >> >>> >>> > What postulates are you using? This list of postulates also contains that > same one: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/qm.html > > >> "The wavefunction or state function of a system evolves in time according >>> to the time-dependent Schrödinger equation" >>> >>> >>> Copenhagen says the superposition remains so long as the system remains >>> isolated (but is less than clear on what it needs to be isolated from: e.g. >>> Wigner's >>> friend <https://en.wikipedia.org/wiki/Wigner%27s_friend>). Therefore >>> it adds an addendum to postulate 5, namely that the system only evolves >>> according to the Schrödinger equation while it is isolated, and when it is >>> not isolated (i.e. being observed), that it does not evolve in time >>> according to the Schrödinger equation. >>> >>> >>> Schrödinger's cat experiment was initially meant to show QM was >>> incomplete. >>> >> >> >> *Not just that, but that there was a problem with the INTERPRETATION of >> superposition of states, which leads directly to a cat being alive and dead >> simultaneously. AG* >> > > Yes, so you see, even at that time, they knew simple experiments, like > listening for a click of a Geiger counter led to superpositions of states > in the wave function. > > And yes, it did imply that the result would lead to a cat being alive and > dead simultaneously in the wave function (though not in any one branch). > The problem was they had a mental block, perhaps not unlike your own, which > made them refuse to consider the idea that reality matched the equations > they developed and that the superposition was real and there were multiple > branches containing all possibilities. > > It wasn't until 1957 that Hugh followed his teacher's (Wheeler) advice, to > see what the theory predicts of our experience, and compare it to what we > actually see. It was in doing this that Everett showed no one experimenter > would see a live and dead cat, because that experimenter himself becomes > part of the superposition of the cat, and so only one outcome is observed > by each instance of the experimenter despite that all outcomes occur in the > wave function. > > >> >> >>> It was only later in his life that Schrödinger realized his equation, if >>> true (and always obeyed), led to many worlds >>> >> >> *Maybe the SWE is not always obeyed; only prior to a measurement.* >> > > This requires some magic properties of observers to collapse the wave > function. It requires that quantum computers be unable to execute some > programs (conscious ones), and it also leads to new problems like how do > you explain Wigner's friend, and what separates a measurement device from a > conscious observer? In short, this idea doesn't really work, and worse, it > is unnecessary: Our observations are consistent with the idea that the SWE > is always obeyed. So there is no reason to modify the theory. > > >> >> * Moreover, if the wf is epistemic only, it can change instantaneously as >> in the example Bruce gave of a horse race (not really a quantum system but >> illustrative anyway); the probabilities change as the race ensues, but when >> it ends and the winner is known, the probabilities change instantaneously a >> the finish line. Maybe this is the case with qubits; they toggle >> instantaneously between the two possible states, but are never in both >> states simultaneously. IOW, your model of how quantum computers function >> might be totally wrong in a conceptual sense, but is useful in their >> construction. AG* >> >>> >>> >>> > You are suggesting that two things can happen in the same time with the > same qubit. How is that not the very definition of simultaneous? > > Jason >
*English is not Bruno's native tongue. Perhaps it's not yours. 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. For more options, visit https://groups.google.com/d/optout.
