Re: PHYS; Quantum Teleportation

Wayne Hayes (
Sat, 13 Dec 1997 12:21:33 -0500

John K Clark <> writes:

>Wayne Hayes <> On Thu, 11 Dec 1997 Wrote:
> >This is the crucial bit of (disappointing) information. I looked
> >carefully into this when the idea was originally annoucned, and
> >decided that "teleportation" was definitely the wrong word. It
> >is *not* teleportation in any sense whatsoever. It is the merely the
> >ability to transfer the exact quantum state of one particle to an
> >identical particle.

>What more you could possibly demand of teleportation?

How about being able to duplicate macroscopic objects, including all
the details of the relations between adjacent atoms, molecules, their
temperature, chemical bonds, etc. None of this *needs* quantum
mechanics, because these properties can be described classically. You
could argue that we'd need quantum information, but we don't know that,
and it's certainly not obvious.

I suppose I should clarify that by "quantum state", I mean things like
the spin, which are describable only by quantum mechanics and by no
other branch of physics. Thus, things like momentum and position and
mass don't qualify, because they can be described classically.

Another major difference between this "teleportation" and true
teleportation is that, ideally, teleportation would be able to
duplicate the object at the far end *without* the need for raw material
at the other end. For example, being able to teleport something into
orbit is impossible unless you can build the object from *nothing* at
the far end. (Well, not *nothing*. You'd have to get the energy from
somewhere, possibly the vacuum.) The "teleportation" being discussed
here does nothing of the sort. It can't dulpicate a molecule, all it
can do is transfer the quantum state of, say, a molecule of H2O to
another H2O molecule far away, but *you need an H2O molecule at the
other end*. It says nothing about *building* an H2O molecule if all
you have is H and O. And of course if it's something more complex,
like a brick, then you need a brick at the other end (a *completely
identical* brick, in all respects down to every last atom in every
position, except the quantum state of all its constituent atoms and
molecules), and all this process does is duplicate the quantum state of
the brick. Big deal. Do you think the quantum state of the brick is

>The quantum state is all there is to say about an object.

I hope I've clarified this above.

>The exact quantum state of your brain is almost certainly far more
>information than you'd need to duplicate consciousness, but it's definitely
>not irrelevant.

It may or may not be relevant. You've made no argument that it is.
Please do so.

>An MRI scanner will change the quantum state of your brain and thus it will
>change you

Changing the spin of some of the particles in my brain does not change *me*.
As far as I know, the latest research on how memory works seems to indicate
memories are stored by chemical reactions that re-arrange molecules between
neurons. The spin of atoms that constitute the molecules is irrelevant.