Re: [gentoo-user] Question of quantum computer

[Rich Freeman <rich0@gentoo.org>]

On Thu, Apr 2, 2015 at 11:30 PM,  <wabenbau@gmail.com> wrote:
> <wabenbau@gmail.com> wrote:
>
>> with the movement of particles. It is a phenomenon that results from
>> the quantum entanglement of e.g. two electrons and has to do with the
>> nonlocality of such phenomenons. When you measure the quantum
>> attributes of one of these two electrons you instantaneous influence
>> the quantum attributes of the other one, regardless of its distance.
>
> Correction: I meant photons and not electrons. Sorry for this.
>

Since others have done a decent job explaining some of the basics
here, I'll just point out that quantum affects apply to all matter and
energy, not just photons.  It just doesn't tend to be noticeable for
anything of significant size except in very unusual situations.

Electrons are fundamental particles (as best we know) and are very
much subject to quantum effects.  In particular the wavelike
characteristics of photons are responsible for behavior like the UV
absorbance of your suntan lotion, or the fact that just about anything
that conducts electricity well tends to look metallic/shiny even if it
doesn't contain something you'd consider metal.  I remember the first
time somebody showed me a conductive polymer and marveling that it
looked like a little strip of metal-coated plastic that you might find
connecting two circuit boards (this was back in the 90s - conductive
polyers are a bit more mainstream now).

In truth, the wavelike characteristics of electrons are important for
virtually all aspects of their behavior since they are so small, but
I'm just pointing out some manifestations that are more visible to the
naked eye.

I agree with the earlier comment that I doubt you'd ever try to run a
general-purpose operating system on a quantum computer.  If they ever
became truly mainstream the most likely configuration would be as a
separate module that would be utilized for certain problems, much like
a DSP or a GPU or an FPGA often gets used today.  They are
non-deterministic in nature (or are at least thought to be and might
as well be for practical purposes - I'm not convinced that anybody has
proven that quantum behavior is truly non-deterministic).  Most
quantum algorithms would be paired with conventional computers.  If a
quantum chip tells you that there is a 95% cumulative chance that
somebody's private key is one of these 50 candidates, that is probably
more than adequate since you can brute force 50 keys in a millisecond
and find the right one.  They're going to tend to be used for needle
in a haystack problems where once you get rid of 99.999999999999% of
the haystack the problem is no longer difficult.

-- 
Rich