Posts by Paul Kinsler 1054 publicly visible posts • joined 9 Aug 2007
I once read some Bertrand Russell, and had to read each sentence twice in order to understand it and its in-context meaning. Some time you just have to keep banging the (mental) rocks together and hope it eventually becomes clear.
But if you'd prefer a more IT angle, why not try this instead?
"When does a physical system compute?"
http://arxiv.org/abs/1309.7979
This sort of thing mostly works for me, although I wake seconds earlier, not minutes. If not, then the light from my trusty old Zaurus's screen (as it wakes) wakes me, and if not that, then it's really rather pleasant alarm chirp.
The most exciting radio alarm event I've had was when Mark F decided to play Ministry's "Jesus built my Hotrod" on 4ZZZ at 6:55 one morning, just in time for my usual wakeup. Thanks, Mark!
The only way you get light to not travel at lightspeed is to make it interact with something. E.g. in water, visible light interacts with the water molecules, and it slows by about 30% (hence the refractive index of 1.5). To make light really slow, you have to get it to interact very strongly - in this case, using a specific frequency of light tuned to specific transitions in carefully managed rubidium atoms.
This "slow light" therefore, is a rather misleading name - it isn't just light - it's a strongly coupled light-matter system, which some would prefer to call a polariton.
I can therefore only assume the down votes were for the poor quality joke.
Er, nope. You can split photons (although perhaps its better to call it conversion) using an optical nonlinearity, as long as you conserve energy. And since the "colour" of a photon depends on its energy (frequency), splitting a high frequency "blue" photon will (can) give you two "red" ones. And with a different setup you can produce photon pairs with mismatched colours.
I agree the general state of New Scientist is depressing. While I stand by my belief that BBC reporting should remain at a very broadly accessible level, NS is exactly the kind of publication which should pitch to a higher level - indeed, I thought that would have been the entire point of a magazine with that name. That said, when some of my work was reported in NS, I was perfectly happy with the result.
I also distinguish between "(news) reporting", which need not (and imo perhaps should not) be technical at all, especially in the mass media, since the point of news reporting is primarily to make the audience aware of something. This is distinct to features or documentaries, which people usually choose to watch, and where greater expectations of their knowledge are entirely appropriate.
As for "an essential part of the [scientist] job description is to ensure that society gets dragged along with one. The two aspects of the job are hand in glove", I would like to agree. But media & outreach interaction can be a vast time sink, and while I do not begrudge it, it can and does affect research output; and, further, not all scientists are very suited to it, and in many cases, neither is their research topic. By all means call for a larger cohort of science communicators, which is indeed the current trend, but expecting all scientists to turn into some sort of media/outreach enthusiast is neither practical, nor a good use of their time and resources.
> My generalised perception of younger generations is that they are less likely to look something
> up unless it is some fickle celebrity nonsense.
On the face of it, this is a plausible claim. But my understanding of school education these days is that is (at least) intended to promote more self directed learning. Whatever its failings, why would this make "younger generations" less likely to look non-celeb stuff up? So, can anyone provide evidence that it is actually true?
In my experience as a physicist, who occasionally has got media interest, science journalists are well motivated and do the best they can at converting quite difficult things down into a form digestible to their (target) mass market. As for "there is no excuse for general publications to assume all of their readers have no knowledge at all", well, the great majority of their audience probably does have no useful knowledge at all (i.e. on the specific subject being presented). Why should the majority be excluded from mass market reporting? You knowledgeable types can just feel all smug at your extreme cleverness - and know enough to go and find a more specialist publication. Just treat the mass media reporting as a supply of adverts, or trailers, for the real sci/tech story.
So if big data isn't "big" then "big data" is a pretty silly name for it. Since supposedly the phrase is used to indicate a soup of factoids elements with had to discern structure, we need a better name. Random stuff assembled together in a way posing as something interesting? Hmm... the art world may have got there first ... how about we just call it "dada" (singular "dadum") instead?
Any professional climate scientist would need a thick skin to even contemplate posting commentary here. Climate debate in forums such as this is a pretty ugly process, and, in fact, tends to have very little to do with any of the formal scientific output - it's largely based around rehashed (& sometimes misread) press releases, superfically relevant technical issues, and/or poorly-founded assumptions about conspiracies, groupthink, or special-interests (on any side of the argument).
This thread is a brilliant example of an internet forum "climate debate". But not so much a brilliant example of any science. Really, what would some putative "regtard" climate scientist have to offer this thread? And what would it offer them? Would it really be worth it? Do you really think you could convince them it would be worthwhile? No, really?
Costly but worthless gifts facilitate courtship
Proceedings of the Royal Society B: Biological Sciences, Vol. 272, No. 1575, p1877-1884 (2005)
doi:10.1098/rspb.2005.3152
by Peter D. Sozou, Robert M. Seymour
What are the characteristics of a good courtship gift? We address this question by modelling courtship as a sequential game. This is structured as follows: the male offers a gift to a female; after observing the gift, the female decides whether or not to accept it; she then chooses whether or not to mate with the male. In one version of the game, based on human courtship, the female is uncertain about whether the male intends to stay or desert after mating. In a second version, there is no paternal care but the female is uncertain about the male's quality. The two versions of the game are shown to be mathematically equivalent.
We find robust equilibrium solutions in which mating is predominantly facilitated by an ‘extravagant’ gift which is costly to the male but intrinsically worthless to the female.
By being costly to the male, the gift acts as a credible signal of his intentions or quality. At the same time, its lack of intrinsic value to the female serves to deter a ‘gold-digger’, who has no intention of mating with the male, from accepting the gift. In this way, an economically inefficient gift enables mutually suitable partners to be matched.
Further to the "unscientific" claim regarding the use of these words, I did a quick search on the APS website for journal papers containing all three words: there were 112k hits. As a quick check against mismatches, notably regarding "May" as e.g. a date or part of a name rather than a Word, I checked 10 of those (with a slight bias towards those with May in the dates), and found only 1 without May as a word.
This would suggest either that that the APS (see http://publish.aps.org/) has published many tens of thousands of unscientific articles, or that instead, contrary to your assertion, that "may", "might", "could" indeed do have a perfectly normal place in the scientific literature.
In fact, scientific papers often contain words like "may', 'might', 'could', etc Notably in the abstract, introduction or conclusion, when trying to explain the motivation of the study, or to communicate why they think the results are or might be important. Typically the phrases using these words are rather distinct from the specific scientific conclusions reached or methodology used.
However, (media or commentator) reporting of the results tends to focus on those more exciting "may', 'might', & 'could' parts, especially since the technical details are usually way beyond the educational level of their readership.
I think you meant to say: follows on from the concept as proposed by McCall et al in J. Optics (2010/11), followed up by an experiment at Cornell (published in Nature 2012).
And re "but when it comes to security the ability to drop one's data into a time hole isn't quite as useful as it sounds cool" -- what, sounding cool isn't a useful thing? I mean, it got you to report on it, didn't it? :-)
To clarify - the "hidden variables" superluminal signalling is only partial; you can only extract information once you get the other part - but unfortunately that has to be sent in the ordinary way - i.e. by lightspeed limited means.
Wires are old hat. Better to use optical fibres, since frequently they can also act as both the sensor and transmission medium, and are largely immune to most sources of electrical and magnetic interference (although properly designed, they can act as E or M sensors as well). And if you use them to make an interferometer, they can also be fantastically sensitive.
Its impossible to send information FASTER THAN LIGHT, because in order to know whether your measurement ("here") is an encoded 1 or 0, you need to compare it against the other distant measurement ("there"). E.g. if they both are the same, it's "1", if they differ, its "0". So to understand your result, you have to wait for the results from over there to be sent to you here, and that waiting time depends on the speed of light.
No, it isn't that strong.
More specifically, the atoms/molecules in the wire are held together with electromagnetic fields, whose (maximum) speed is that of light. Therefore, the effect of your pull can also only be transmitted at the same speed; the wire therefore can never have "no give" and be as strong as you would like..
And as long as you insist that your wire is made of stuff subject to a relativistic universe and its maximum speed, that same holds.
You can interpret QM predictions of separated measurements on entangle systems like this in two ways:
(a) You insist that any quantum uncertainty might be a result of ``hidden variables'', and so follow the rules of classical (ordinary) probability. This requires the two parts of the experiment to be able to signal to each other instantaneously: i.e. the so-called ``spooky action at a distance''
(b) You prefer to retain the speed-of-light speed limit for cause and effect, but at the cost of disallowing hidden variable (standard probabilistic) models, and thus need to describe things using complex probability amplitudes - i.e. quantum probability.
Most physicists prefer to choose (b), because they prefer to retain causality over a model respecting classical probability theory.
Nevertheless, it is valuable to test both ideas. As I understand it, here the authors' have said: if we choose a hidden variable interpretation (choice (a)), what is the experimental bound on the speed of information transfer?
This doesn't mean that the interpretation (a) is the ``true'' interpretation. It doesn't even mean that the authors necessarily prefer (a) over (b). But it does tell us something about how things (might) work /if/ (a) were the best interpretation.
"speed of light" might mean one of two different things, depending on context. Either the fundamental speed limit as determined by relativity, which is the same as the speed of light in a classical vacuum. Alternatively, it might mean the spped that light gets from one end to the other of this stuff I have here (which will be less than the other definition).
Here, the context given, i.e. "99.7% of the speed of light" strongly suggests that the first "relativistic speed limit" definition is the one meant.
Lastly, most materials and waveguides have (both) temporal and spatial dispersion - their wave speeds vary with frequency (wavelength). This variation gives rise to a "group velocity", which is the speed a pulse will travel through, and this need not be especially similar to the (usually quoted) phase velocity. Generally, high-frequency (short wavelength) signals feel the medium/waveguide less; this has to be true in the very high frequency limit or something has gone wrong with causality. This high frequency behaviour means that you can get optical precursors that travel at near (vacuum) c even in a material, even if you send in an otherwise unremarkable pulse into a "slow" medium.
The author's original paper states: "This novel radio technique allows the implementation of, in principle, an infinite number of channels in a given, fixed bandwidth, even without using polarization, multiport
or dense coding techniques."
Note the "in principle", this is a pretty strong qualifier, essentially meaning (in this context), "ignoring all practical constraints, and only considering (this) simple theoretical model".
The big constraint here is alignment - the antennae need to be aligned, because you wont be able to get good enough OAM information from the edge of the beam, especially if its centre is off the receiving antennae. So mobile might be ok, but only if lined up carefully .... not if you are wandering down the street! This is more of a prepared fixed-point to fixed-point scheme.
No - there are two circular polarization states; but this is not the same thing as the (orbital) angular momentum of a light beam. You can have a "plane wave" in LH or RH circular polarization states without any spatial structure, but for OAM you need it. E.g. try looking up "optical vortex" on wikipedia.
Actually, what Shultz said is not "mock-intellectual mumbo jumbo", is was in fact reasonably well founded.
For myself, I am unsurprised that you can get extra bandwidth by adding a spatial encoding as well, although its practical utility might turn out to be rather limited. But then they published in (the open access) New. J. Physics,
so their idea of utility is not the same as that of an engineer.
And "like those idiots who try (and fail) to apply GR to phenomena that can be satisfactorily explained with Newtonian mechanics" ... actually this is a reasonable thing to do. I have on my bookshelf a copy of Schutz "A first course in general relativity", and one interesting exercise in there is to show how GR reduces to a Newtonian-like theory in the appropriate limit. It might be a bit pointless from an engineering perspective, but not for physics.
See e.g. http://arxiv.org/abs/0711.1751 (in particular fig.2, evolution of nose size by Myr)
Paleontological Tests: Human-like Intelligence is not a Convergent Feature of Evolution
Charles H. Lineweaver
We critically examine the evidence for the idea that encephalization quotients increase with time. We find that human-like intelligence is not a convergent feature of evolution. Implications for the search for extraterrestrial intelligence are discussed.
I doubt very much that the science was driven by a desire for publicity. Most likely they just worked out a way of making this (scientifically) interesting and useful experiment* amenable to public consumption, and when the Reg saw the press release they rewrote it a bit and stuck it on here. Please do not confuse the press release/media report with the actual science.
As for its simplicity: very possibly you could get this result in a computer simulation, or even predict it with a mathematical description, but it's very nice to see it in a system involving real biology as well. And stripping back the system to the bare minimum enables you to discover general principles that are utterly obscured in something as complicated as a real-world ecosystem. Extracting simple answers from a confusing mess is /good/ science[*], after all, the utility of statements like "it's all too complicated, we haven't got a sodding clue what's going on!" is somewhat limited.
[*] and of course scientists also make a point of understanding the limitations of those simple answers.
It's worth noting that science papers these days have two parts. First, there's the science, which is usually either mathematically or experimentally /hard/, and so is ignored by everyone except scientists, and especially by internet commentators (even in those cases where the paper is free to view). Second, there's the wrapping, which provides some context and a few suggested applications.
Since the science (with all its details and caveats and approximations and assumptions) is largely impenetrable to all but the specialist, this second "context" part is vital in communicating the basic ideas, so that non- or near- specialist can decide whether or not they want to spend the necessary time trying to really understand the result, so that they might use it, or extend it, or adapt it.
The "9/11" bit is merely this context, and scene-setting. It shows (or suggests) that the science bit might plausibly be expected to turn into something useful somewhere down the track - perhaps soon, perhaps not. It help you, the non-specialist understand the kind of problem of situation the research addresses. IT IS NOT THE RESEARCH ITSELF! (it is more akin to window dressing).
In particular I direct the reader to note the journal it was published in: Physical Review Letters, which is a research journal, and not one for applied-spying-techniques and/or viral-marketry.
And as for that "taxpayers blank cheque", please note that the UK spends about the same on catfood every years as it does on basic research. Academic salaries are not that great. I suspect it is rather similar in most other countries, if not worse.
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