A quantum computer is a device, a technological
device that in principle would harness the full capacity of quantum mechanics to undertake
calculations that a standard computer would be absolutely unable to achieve. One way of
thinking about it is this. There’s an approach to quantum mechanics where one imagines that
there are many in some sense parallel realities moving along in some larger environment if
you will. Where, for instance if I want to measure an electron, quantum theory says well
there’s a 50 percent chance it’s there and a 50 percent chance it’s over there.
Now what does that mean? Well one interpretation says well there’s actually two universes
and in one universe the electron is here and in another universe it is over there. That’s
kind of a crazy sounding idea but a quantum computer perhaps can harness that by doing
some calculations over here and other calculations over there in parallel. Now it’s doing in
some sense twice as many calculations as a classical computer existing in one world would
be able to do. Now imagine taking that idea and spreading it over all of the possible
realities allowed by quantum mechanics. Now you’re harnessing all of these different
worlds if you will to do all of these calculations in parallel much faster, much more powerful.
Doing calculations that in a single universe would be impossible. So this is one way of
thinking about it and it offers amazing possibilities and we just need to see how successful we
are at harnessing these ideas to actually put it into practice. And we don’t know
yet. We’ll see going forward but it’s an exciting possibility.