[ExI] John Preskill on Quantum Computing

[Adrian Tymes]

On Wed, Jun 13, 2018 at 6:39 PM, John Clark <johnkclark at gmail.com> wrote:
> On Wed, Jun 13, 2018 at 3:51 PM, Adrian Tymes <atymes at gmail.com> wrote:
>> The metaphor about the book came off as misleading to incorrect
>
> Given that Preskill is one of the world's leading experts on quantum
> information and is the Richard J Feynman J Feynman Professor of Theoretical
> Physics at the California Institute of Technology

...is an appeal to authority, and says nothing about the statements to
which I objected.

>> going off on how it's all mysterious and spooky
>
> Niels Bohr said it best:
>
> "Anyone who is not shocked by quantum theory has not understood it."

Anything that is initially shocking fades from that status as it
becomes more familiar.  This is true even of quantum theory.

To be continually shocked by the same reality is a classic indicator
of failure to comprehend it.  To insist that only those continually
shocked may truly understand is to, frankly, lie.

>> Rather, if you look at one entangled particle, the unusual thing is that
>> you then know properties about its entangled partner - even if said partner
>> is light years away, you know the information instantly
>
> That is the simplest possible
> example of quantum entanglement involving a single Qbit, Preskill was
> talking about far more complex systems where thousands or millions of Qbits
> are entangled
> , the sort of thing you'd need for a quantum computer.

And?  Each and every one of them is entangled with another particle;
perhaps some pairs might be among that thousands or millions.  This
does not render the whole collection immeasurable.

Unless he is trying to redefine the term "quantum entanglement".  If
so, that is far closer to "hyping up the spooky and mysterious" than
"clearly explaining", and thus is not worth listening to if one is
seeking an explanation.