[extropy-chat] Teleportation Question

[scerir]

Robert Bradbury:

> I don't see what quantum teleportation has to do
> with classical teleportation.

In quantum teleportation you need the entanglement
between the quantum states of two separated systems,
a third quantum state to be teleported from Alice
to Bob, a certain measurement performed by Alice
(Bell state measurement) which deletes the quantum
state to be teleported (no cloning theorem) and
re-creates the quantum state at Bob's location,
and some additional classical information from Alice
to Bob.

(In the new experiment Polzik uses a similar protocol,
to teleport a quantum state. The main difference is
that the entangled systems are not two particles
but a sample of atoms and radiation (a beam
interacting with the sample of atoms).

If the 'Star-Trek' teleportation is the classical one
I think it should not be much different from the quantum
teleportation (I read they also use entanglements and
'Heisenberg compensators').

> In classical teleportation you want an exact copy at a remote location.
> The
> disassembly of the original is commonly part of the equation but I can
> imagine processes where it might not be entirely necessary.  The classical
> quantum states of all of the atoms in the original are IMO *irrelevant*
> from
> a human "teleportation" standpoint [1] -- the quantum state of my brain
> changes far more between going to sleep and waking up or letting my blood
> sugar get too low and I find neither of those upsetting.  And a dumb rock
> doesn't care whether or not it is the "same" rock when it is moved from
> point A to point B.

Well, I tend to agree here. The problem I see (using the usual
quantum protocol) is this one. You can teleport only the 'soul'
(the quantum state) and not the 'body' (the quantum system) [1].
So the questions (imo) are:
- is it possible to teleport the quantum state of a big molecule?
- are there problems due to quantum decoherence?
- assuming that we have the quantum state of a big molecule
  and that we can teleport it, how can we re-create, at a
  distance, non just the 'soul' but also the 'body'?
These are, perhaps, stupid questions, but I cannot
give answers.
s.

[1] http://www.arxiv.org/abs/quant-ph/0408095
there are big problems even if we try to
communicate, with quantum means, simple things
like 'chirality'.