Re First Object NOT Teleported from Earth to Orbit

["Dave Farber" <farber () gmail com>]

Begin forwarded message:

> From: Rodney Van Meter <rdv () sfc wide ad jp>
> Date: July 20, 2017 at 6:05:39 AM EDT
> To: David Farber <dave () farber net>, Dave Farber <farber () gmail com>
> Cc: Rodney Van Meter <rdv () sfc wide ad jp>, ip <ip () listbox com>
> Subject: Re: [IP] Re First Object NOT Teleported from Earth to Orbit
>
> (Dave, I sent this a day or two ago, but if you forwarded it on I missed it. More importantly, I’ve now updated to 
> include the recently-announced Japanese satellite experiment I had missed!)
>
> Gilmore is right.
>
> To extend a little bit, what is “teleported” in quantum teleportation, is a quantum *state* that can’t be analyzed 
> without destroying it. Essentially, you’re moving quantum data from one place to another without learning anything 
> about the data itself; in quantum mechanics, when you measure a state, you destroy any superposition and any quantum 
> entanglement it has, which destroys its usefulness as quantum data.
>
> This article is pretty good:
> http://www.bbc.com/news/science-environment-40594387
>
> Teleportation is useful not only for moving qubits over long distances, but also for changing physical data 
> representations from e.g. the spin of an electron to the spin of a nucleus — roughly, moving a qubit from RAM to 
> disk, if you like.
>
> The experiment is an impressive accomplishment. Jian-Wei Pan’s group is the best in the world at long-distance 
> single-photon work, bar none. He did his Ph.D. with Anton Zeilinger, in Vienna. After returning to China, he has 
> built an incredible group, with tremendous support from the Chinese government. We all knew his team had put up a 
> satellite, but personally I didn’t expect the data (and data rate) to be as good as it is — it’s a hard problem, 
> capturing single photons sent down from orbit! And yet they’ve done it, beating out teams from Canada, Singapore, 
> Japan and Europe that were already doing preliminary experiments, including in space.  See e.g.
> https://www.wired.com/2017/02/physicists-test-quantum-cryptography-playing-catch-photons-plane/
>
> Sasaki-san's group from NICT, here in Japan, at almost the same time announced publication of results from a 2016 
> experiment, QKD from a satellite:
> http://www.nict.go.jp/en/press/2017/07/11-1.html
> http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2017.107.html?foxtrotcallback=true
> They are *not* sending entangled photon pairs to two ground satellites, or creating space-to-ground entanglement. In 
> fact, they’re not using single-photon pulses at all.  They are sending pulses with 2.3*10^8 photons/pulse from the 
> satellite, and receiving an average of 0.1 photons on the ground, after a 78dB loss budget. This is also an 
> extraordinary accomplishment, even if it’s a bit eclipsed by the successive Chinese announcements. If you consider a 
> satellite to be a trusted node, and you connect via QKD to two separate ground stations, you can create ground 
> station-to-ground station shared secret keys securely.
>
>
> Several years ago, Simon Devitt and his collaborators, including yours truly, proposed an alternative to creating 
> entanglement via satellite: shipping error correction-protected qubits via container ship. At the time, I contended 
> that satellite was too hard to pull off across the Pacific, and the first trans-pac entanglement demonstration would 
> be using our technique. Now, I’m not so sure.
> https://motherboard.vice.com/en_us/article/4x34e3/how-cargo-ships-full-of-diamond-hard-drives-could-connect-a-quantum-sneakernet
> https://www.nature.com/articles/srep36163
>
> Also, since I’m here, an announcement:
>
> This October, we are doing a free MOOC on quantum computing. I’ll send details in a separate email.
> https://www.futurelearn.com/courses/intro-to-quantum-computing/
>
>
> > On Jul 17, 2017, at 5:36 AM, Dave Farber <farber () gmail com> wrote:
> >
> >
> >
> > > Begin forwarded message:
> > >
> > > From: Mary Shaw <mary.shaw () gmail com>
> > > Subject: Re: [IP] Re First Object NOT Teleported from Earth to Orbit
> > > Date: July 14, 2017 at 9:29:40 AM EDT
> > > To: Dave Farber <dave () farber net>
> > >
> > > In addition, I'm having some trouble with "photon" as a member of class "object".
> > >
> > > Mary
> > >
> > > > On Fri, Jul 14, 2017 at 6:16 AM, Dave Farber <farber () gmail com> wrote:
> > > >
> > > >
> > > > > Begin forwarded message:
> > > > >
> > > > > From: John Gilmore <gnu () toad com>
> > > > > Subject: Re: [IP] Re First Object NOT Teleported from Earth to Orbit 
> > > > > Date: July 14, 2017 at 3:05:34 AM EDT
> > > > > To: dave () farber net
> > > > > Cc: "ip" <ip () listbox com>
> > > > >
> > > > > > > This is the first time that any object has been teleported from Earth to
> > > > > > > orbit...
> > > > >
> > > > > > No, no, no.  It's not an object that was teleported.  It was
> > > > > > information about an object that was teleported.
> > > > >
> > > > > Uh, from looking at the article, NOTHING was teleported.  They sent up
> > > > > a satellite (using a chemical rocket) that contained some kind of
> > > > > photon detector.  They then sent photons from earth to the satellite,
> > > > > via a more complicated way of shining light upward.  No "teleportation"
> > > > > was involved; the photons got from earth to orbit by the ordinary
> > > > > motion of photons through space.
> > > > >
> > > > > The quantum folks adopted a word ("teleportation") that actually means
> > > > > something else to 99% of people.  Don't be confused.  See:
> > > > >
> > > > >  https://en.wikipedia.org/wiki/Teleportation
> > > > >  https://en.wikipedia.org/wiki/Quantum_teleportation
> > > > >
> > > > > Note that to "teleport" one quantum state requires doing classical
> > > > > communication of two bits.  This isn't an example of a science-fiction
> > > > > quantum encrypting ansible that spits information instantly over vast
> > > > > distances by using two local stores of entangled qubits.  It doesn't
> > > > > work faster than the speed of light.  It's just quantum guys using
> > > > > confusing terminology for some odd properties of matter.
> > > > >
> > > > >   John
> >
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