On Tue, Aug 21, 2018 at 11:28 PM Brent Meeker <[email protected]> wrote:
> > > On 8/21/2018 9:01 PM, Jason Resch wrote: > > > > On Tue, Aug 21, 2018 at 10:50 PM Brent Meeker <[email protected]> > wrote: > >> >> >> On 8/21/2018 7:38 PM, Jason Resch wrote: >> >> >> >> On Tue, Aug 21, 2018 at 7:43 PM Brent Meeker <[email protected]> >> wrote: >> >>> >>> >>> On 8/21/2018 3:37 PM, Jason Resch wrote: >>> >>> >>> >>> On Tue, Aug 21, 2018 at 5:00 PM Brent Meeker <[email protected]> >>> wrote: >>> >>>> >>>> >>>> On 8/21/2018 2:40 PM, [email protected] wrote: >>>> >>>> >>>>> 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? >>>>> >>>> >>>> It's no more impressive numerically than an electron wave function >>>> picking out one of 10^30 silver halide molecules on a photographic plate to >>>> interact with (which is also non-local, aka simultaneous). >>>> >>>> >>> Well consider the 1000 qubit quantum computer. This is a 1 followed by >>> 301 zeros. >>> >>> >>> What is "this". It's the number possible phase relations between the >>> 1000 qubits. If we send a 1000 electrons toward our photographic plate >>> through a 1000 holes the Schrodinger wave function approaching the >>> photographic plate then also has 1e301 different phase relations. The >>> difference is only that we don't control them so as to cancel out "wrong >>> answers". >>> >>> >> >> The reason I think the quantum computer example is important to consider >> is because when we control them to produce a useful result, it becomes that >> much harder to deny the reality and significance of the intermediate >> states. >> >> >> Which is why I'm pointing that, while important from our view of it as a >> computation, from a physical viewpoint it is nothing unusual. If I poked a >> 100 pinholes in a screen and shone my laser pointer on it there would the >> same number of "intermediate states" between the screen and a photo >> detector. >> > > Okay. But this example tends to ignore the intermediate steps of the > computation, in a way that is easier to look over. > > >> >> For instance, we can verify the result of a Shor calculation for the >> factorization of a large prime. We can't so easily verify the statistics >> of the 1e301 phase relations are what they should be. >> >> >>> This is not only over a googol^2 times the number of silver halide >>> molecules in your plate, but more than a googol times the 10^80 atoms in >>> the observable universe. >>> >>> What is it, in your mind, that is able to track and consistently compute >>> over these 10^301 states, in this system composed of only 1000 atoms? >>> >>> >> Are you aware of anything other than many-worlds view that can account >> for this? >> >> >> I don't see anyway a many-worlds view can account for it. All those >> qubits have to be entangled and interfere in order to arrive at an answer. >> So they all have to be in the same world. Your numerology is just counting >> interference relations in this world, they don't imply some events in other >> worlds. >> > > Where are these interference relations existing? We've already > established there are not enough atoms to account for all the states > > > That's because the states aren't things, they are entanglements, i.e. > relations between things. That's why the numbers are in exponential in the > number of things. They are not things themselves, so it's specious to > compare them to atoms. > > in the whole observable universe (one world), nor are there enough Plank > times to account for iterating over every possible state involved in the > computation in (one world). So where are all of these states existing and > being processed? > > >> >> >> >> >>> >>> >>>> Also note that you can only read off 200bits of information (c.f. >>>> Holevo's theorem). >>>> >>>> >>> True, but that is irrelevant to the number of intermediate states >>> necessary for the computation that is performed to arrive at the final and >>> correct answer. >>> >>> >>> But you have to put in 2^200 complex numbers to initiate your qubits. >>> So you're putting in a lot more information than you're getting out. >>> >> >> You just initialize each of the 200 qubits to be in a superposition. >> >> >>> Those "intermediate states" are just interference patterns in the >>> computer, not some inter-dimensional information flow. >>> >> >> What is interference, but information flow between different parts of the >> wave function: other "branches" of the superposition making their presence >> known to us by causing different outcomes to manifest in our own branch. >> >> >>> Also, many quantum algorithms only give you an answer that is probably >>> correct. So you have to run it multiple times to have confidence in the >>> result. >>> >> >> I would say it depends on the algorithm and the precision of the >> measurement and construction of the computer. If your algorithm computes >> the square of a randomly initialized set of qubits, then the only answer >> you should get (assuming perfect construction of the quantum computer) >> after measurement will be a perfect square. >> >> >> Right. There are some quantum algorithms that give probability 1 answer. >> >> >> >>> >>> Quantum computers will certainly impact cryptography where there's heavy >>> reliance on factoring primes and discrete logarithms. They should be able >>> to solve protein folding and similar problems that are out of reach of >>> classical computers. But they're not a magic bullet. Most problems will >>> still be solved faster by conventional von Neumann computers or by >>> specialized neural nets. One reason is that even though a quantum >>> algorithm is faster in the limit of large problem size, it may still be >>> slower for the problem size of interest. It's the same problem that shows >>> up in classical algorithms; for example the Coppersmith-Winograd algorithm >>> for matrix multiplication takes O(n^2.375) compared to the Strassen >>> O(n^2.807) but it is never used because it is only faster for matrices too >>> large to be processed in existing computers. >>> >> >> So where do you stand concerning the reality of the immense number of >> intermediate states the qubits are in before measured? >> >> >> It's just like flipping two rocks in a pond and being amazed at the >> immense number of points at which ripples interfere before they determine >> the wave that hits the sand bar. >> > > Except there are more ripples than bits in the Hubble volume, and more > state transitions than there have been Plank times in the age of the > universe. > > > Not ripples, the analogy is intersection of ripples. The huge numbers are > combinatorics. They are abstract "states" only in the sense that the > *relation* of two different atoms in a ripple is a state. > So here we have an "abstract" thing with concrete effects on our reality. I thought you were one for "if it kicks back, then its real". Jason -- 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.
