(Wayne Throop) wrote:

The thing is, you're moving a state, not a particle; software not
hardware. And moving a state is, in the classical world, communication,
not portation.

The word "moving" is what makes me happy with calling it teleportation.
Communication copies information from place to place (or time). Quantum
teleportation cannot be used to make copies; it can only be used to move.

Software is stuff you can send over an ethernet
connection, hardware is stuff you can't.

Classically, that simple test is a good distinction. In the spirit of
vigorous debate, however, I can counter it in two fundamentally
different ways.

First, what you can send over a network is information. You need the
appropriate setup at each end to make the transfer work, which in the
simple case is basically general-purpose computers following the same
protocol. You can send an appropriately detailed series of bits which
can be executed on a computer and run a copy of a program that way. But
you can also send an appropriately detailed description of a piece of
hardware to a machine shop and have a copy of a physical object produced
that way. The simple test fails to recognize the possibility of an
established infrastructure which makes the distinction irrelevant.

Second, quantum teleportation requires entangled particles, which
unarguably cannot be sent over a network. By the simple test, it is not
software.

And what's going on here
is you're sending a bit of classical information, and a packet of
quantum spookiness, which when you get it where you're going you can
induce a particle to aquire here a state some particle there lost.
Which seems much more like sending a description of something to
do to an object than anything else.

It seems that way because that's exactly what it is, and I do not
dispute it. The result of the process, however, is that a quantum state
has been relocated from one place to another without having it visit any
place in between, and I think relocation without traveling is perfectly
compatible with the definition of teleportation.

You're saying limits of the quantum world make it a portation, yet
even so, it is *still* going to be inevitably misleading because of the
tranditional connotation of the word "teleport".

I'm actually saying that quantum limitations make it impossible to
duplicate a state completely, while still making it possible to relocate
that state.

And one simple way to tell that it's misleading, is that people
immediately say "gosh, maybe we can scale this up to get treknological
transportation", whereas you haven't even started to be able to transfer
coherently a whole object, or indeed a particle of any sort. And the
ability to transfer, oh, spin state of some of the particles on a
quantum level doesn't even start to head in that direction.

Hrm? Quantum teleportation has been done *only* with particles.

Now of course, everybody is their own Humpty Dumpty. And there are
rational justifications for the usage as you've just shown. But using the
term "teleport" for this operation is inevitably going to be misleading,
whether it's "proper" or not.

If that's what's bothering you, consider that the term "telephone" is
just as misleading. It implies sound at a distance, when it really
involves an intermediate stage of decidedly non-sonic transmission. It
sounds like your objection to the term is based not on what it means but
on what you imagine other people might think it means.

You do have a valid point, as such misunderstanding of what it means has
been demonstrated in this very thread. But if I were to refuse to use
jargon just because not everyone understands it, I'd lose a significant
fraction of my vocabulary.

And after all, people call it quantum cryptograpy, implying
communication, not quantum postal service, implying portation.
Which seems altogether less misleading.

Quantum cryptography is a different process. It does not use entangled
photon pairs to move unmeasured states around. It measures the photons
directly to simultaneously get the same random number at two different
locations.