On Wednesday, August 22, 2018 at 2:19:43 PM UTC, Jason wrote:
>
>
>
> On Wed, Aug 22, 2018 at 2:06 AM <agrays...@gmail.com <javascript:>> wrote:
>
>>
>>
>> On Tuesday, August 21, 2018 at 10:30:01 PM UTC, Jason wrote:
>>>
>>>
>>>
>>> On Tue, Aug 21, 2018 at 4:40 PM <agrays...@gmail.com> wrote:
>>>
>>>>
>>>>
>>>> On Tuesday, August 21, 2018 at 8:02:52 PM UTC, Jason wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Aug 21, 2018 at 2:20 PM <agrays...@gmail.com> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> On Tuesday, August 21, 2018 at 3:04:45 PM UTC, Jason wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Aug 15, 2018 at 1:44 PM <agrays...@gmail.com> wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Wednesday, August 15, 2018 at 2:41:12 PM UTC, Jason wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Wednesday, August 15, 2018, <agrays...@gmail.com> wrote:
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Wednesday, August 15, 2018 at 11:49:04 AM UTC, Bruno Marchal 
>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 15 Aug 2018, at 12:36, agrays...@gmail.com 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 <meek...@verizon.net> 
>>>>>>>>>>>>> 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*

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