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August 23, 2005


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Your list of papers is, not surprisingly, dominated by superconductivity - the BCS theory had just been published in 1957, and it took the world of physics by storm.

Late 1950's is IMO too early for NSA to be thinking about "entanglement" - that concept finds its natural foundation in Bell's 1964 paper, which did not get a whole lot of attention at first. To be sure, the basic idea is implicit in Bohm's 1950's work, not to mention EPR 1935, but these earlier works have a very different emphasis. It's a subjective judgement, but my gut tells me that a brilliant NSA mathematician with some background in quantum theory might have been able to discern cryptographic applications in Bell 1964, but not in Bohm or EPR.


There's a fair amount of electron spin and nuclear magnetic resonance research as well, which piqued my interest. Related to BCS theory, but indirectly.

My hypothetical NSA researcher in 1956 probably wouldn't be thinking quantum cryptography or computation, but he (almost assuredly 'he', dammit) might be thinking "untappable/perfectly secure communication" or even "superluminal communication", depending on his take on Einstein-Podolsky-Rosen and Bohm. So I guess I am wondering if someone at or through the NSA had prefigured Bell by a few years, or even Aspect.

Will Baird

Y'know, this almost sounds like a pulpish sfnal book, blended with a bit of Clancy and alternate history, waiting to be written, Carlos. Perhaps you and the Muirs ought to get into the fictional writing arena. Certainly wouldn't hurt the genre to get an AH spy novel.

ObWI: NSA develops an /perfectly/ secure telecom system circa 1960. How do the Soviets react?

Bernard Guerrero

"Anyway, here's the list of papers for (strike)my readers(/strike) Bernard"

Should I consider this an honor or have your daily hits just gotten really attenuated? I can't believe folks don't eat this stuff up.

Anyway, "untappable/perfectly secure communication or even superluminal communication" is the first thing I thought of when you said entanglement. Most likely the former, unless NSA has been keeping some _really_ cool secrets besides. (On an HDTD side-note, I seem to recall that one of Anderson's recurring motifs was Flandry's constant lookout for some means of direct supraluminal communication, as opposed to via the FTL equivalent of a packet-steamer.)

Possibly of interest: http://colossalstorage.net/home_entangled.htm




Of particular note in that last, "1. Wiesner, S., "Conjugate coding", Sigact News, vol. 15, no. 1, 1983, pp. 78 - 88; original manuscript written circa 1970."

Will, "ObWI: NSA develops an /perfectly/ secure telecom system circa 1960. How do the Soviets react?" How would they find out? ;^)

Bernard Guerrero

Different topic:

Take a look at: http://www.econbrowser.com/archives/2005/08/talk_of_recessi.html#more

The first comment is interesting, too. Something there, but then he screws it up later when comparing the energy _remuneration_ of a boyscout and a neurosurgeon. Price levels can fall without the overall level of activity dropping.


Hmm - my previous comment provides an interesting illustration of the "blink" phenomenon. Looking at your titles again, while superconductivity is prominent, it in no way "dominates" the list. I subconsciously (and with the help of two glasses of Ravenswood Sonoma Zinfandel) aggregated a whole lot of papers dealing with the general subject of "collective phenomena in solid state physics" - ferrromagnetism, antiferromagnetism, and so forth - with superconductivity - the most spectacular example of such a phenomenon, which served as a paradigm for research into all of those other phenomena.

I agree that the amount of attention devoted to paramagnetic resonance (only loosely connected to that Paradigm, via spin waves) is curious and worthy of further investigation.

As for EPR/Bohm/entanglement, a provocative WI comes to mind. David Bohm was an interesting character. He was one of the few physicists of his generation who really paid attention to EPR and related philosophical issues - first of all in his Quantum Theory textbook, which is one of the few from that period that pay any attention at all to the Problem of Measurement, and then a few years later in his Hidden Variables papers. He also made profound contributions to solid-state physics - the Bohm-Pines treatment of collective coordinates is one of the seminal papers on the quantum many body problem (and via Pines, who went on to work for Bardeen, there is a direct link from Bohm to BCS. The Bardeen-Pines Hamiltonian for electrons interacting with phonons eventually became BCS after Cooper discovered the pairing phenomenon. Schrieffer was the grad student who put all the pieces together.)

However, Bohm's career in physics was ruined by his past Communist associations. Princeton fired him, and he was unable to get a position in the U.S. during the early 1950's. Eventually he got a position in Britain, but in the meantime he had lost touch with mainstream physics and devoted most of the rest of his career to quasi-mystical pursuits.

So: WI Bohm with different politics ? Specifically, a *Bohm who can be hired by the NSA ? There you go, you don't need to posit a mathematician who appreciates the implication of what Bohm was doing in the mid 1950's, all you need is to get Bohm himself into the NSA !

Doug M.

Correct me if I'm wrong, but if you have FTL communication, then you also have (potentially causality violating) communication through time. No?

Just take two entangled particles, dump one into the linac, and accelerate it at very close to lightspeed for (say) a month. The accelerated particle "thinks" that no time has passed, and is still entangled with its counterpart of a month ago. Voila, you now have a "time radio" that can transmit a single bit from one month in the future.

Working out what the NSA might do with this is left as an exercise for the student.

Doug M.


I ain't getting you. Quantum entanglement is thought to be instantaneous. So causality violations would have to arise from the spacelike intervals between the two particles, not the past history of reference frames of one particle vis-a-vis the other, which shouldn't make any difference.

Bernard Guerrero

Another way of saying what Carlos is saying (I think) would be that an effect, under special relativity, must be part of its cause's future light-cone. It is this property that supra-luminal communications would violate.

Doug M.

I guess I'm confusing them with wormholes. Okay.

But then, how /would/ you use an ansible to violate causality?

Doug M.


Attain enlightenment.


Umm - you guys _do_ realize that "entanglement" does not allow for any sort of meaningful superluminal communication, right? Whatever it is that gets "transferred" in an EPR type of setup, it can't be use used to communicate a causal signal. (Google "Eberhard's Theorem". On second thought, don't - that particular google string pulls up a lot of crap from the lunatic fringe of quantum theory. On third thought, go ahead - most of that stuff is at least amusing, and some of it is instructive. Oh, John G. Cramer isn't crap, not by a long stretch, but it's fair to say that he's pretty far out there - perhaps not onn the fringe, but well out in the penumbra. I think Cramer would agree with that characterization - he's nothing if not bold.)


Yeah, I know; but there's a set of e-mails not on this this comment thread on how to use this in an SFnal setting with some fancy handwaving.

(Why does everyone want me to write a Cold War AH story about the NSA and their sekrit FTL communication device? Do I look like Charlie Stross?)

Paul Park's latest book, A Princess of Roumania (review forthcoming), has an ansible in it, but it's used to talk with the dead, which leads to a very funny line in a rather somber book. ("What are you wearing?")

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