Haven't read the paper, but perhaps they mean they move the dopants out of the way of the (desired) electron trajectories; whilst leaving them sufficiently nearby so as to leave other properties unchanged.
Briefly: something that appears to be information-like gets transmitted faster than light; but, whatever it is, it is of no use to you at all - until you have the chance to correlate it with some ordinary information sent to you in an ordinary (light-speed-limited) way.
If your research grant mandates open access in a manner incompatible with (eg) Elsevier's conditions, then you should not publish results funded by that grant in an Elsevier journal.
"Its content is written by its own flacks" - true of news content, not of their feature articles, usually/often written by the scientists concerned (I co-wrote one on spacetime cloaks last year).
As regards embargoes, they work in that (as far as I can tell) you get a much better hit and a wider spread of publicity than if the story leaks out slowly from various sources. And it is only science news, does it really matter if you hear about that new superconductor/whatever a week later? If it does, then you shouldn't be relying on the news media!
You could, for example, follow journal RSS feeds and the arxiv, and pick up newsworthy science off your own bat without being slaved to press releases and news magazines. You might cultivate a set of scientists and ask them to pass along any interesting stories for you to take a reporter's look at. If so, you might find more diverse set of science stories appearing, not just the latest angle from some boffins who've managed to reference not only Harry Potter, but also Star Trek and safe-cracking bank robbers in their Press Release.
The point is you use the concept, not a specific (optical) implementation.
For example you imagine that by speeding and slowing the clock signal of a target system you can preserve its outputs unchanged from the unaffected case, but nevertheless create a time interval in which you can use the hardware undetected. But at the moment this is just a concept, not a suggested implementation.
"Still, the Riess et al and Perlmutter papers were persuasive direct observational evidence"
And this is what counts: the Nobel Prizes (at least in Physics) /tend/ to be awarded for practical and/or experimental results, rather than theoretical breakthroughs or concepts.
Perhaps remarkably, Maxwell's equations indeed are relativistic, and were so before SR was proposed by Einstein. If you want a plausibilty argument, then consider that SR uses light(speed) propagation to establish a metric, and that Maxwell's equations describe light propagation.
Otherwise, I suggest you go read any EM textbook.
Or ponder why, post-SR, Maxwell's equations are so popular.
Or feel free to invent a theory of non-relativistic light to describe your laser. Good luck with that, eh.
This is the one Singularity that's actually going to happen: The Bubble Singularity, where bubbles of all kinds -- financial, technical, cultural -- arrive faster and bigger and more destructive, all the way to Infinity.
I, for one, welcome our Frothily Singular new overlords, all Infinity of them.
is not really the reduced uncertainty, but one of reduced power - which then minimises error, as (crudely) less photons bounce of the mirrors, so the mirrors wobble less.
This is because to create squeezed light requires a high-power beam to be converted into a lower-power squeezed beam. And the phase uncertainty in the raw unsqueezed beam (required to create a phase-squeezed beam) is about the same as that in the lower-power squeezed beam.
No, it isn't. True Airy beams are very non-local, and in fact (crudely speaking) the reason they don't diffract is that they're already spread out enough (and in the right way) so that the light diffracting out from the middle of the beam is exactly balanced by the light diffracting back from the edges.
A wavelet is a localised mathematical object, useful as a basis with which to describe similarly local, oscilliatory thing - e.g. light beams or pulses.
You could describe arbitrary beams in terms of a basis of "Airy modes", but the Airy functions aren't local enough to match with the wavelet concept.
Superlenses rely on amplifying & controlling the (non-propagating) evanescent excitations; phases arrays control propagating waves. Use of propagating (and typically sinusoidal) waves doesn't eneble as tight a focus as the much better localized (typically exponentially decaying) evanescent components.
is more of a "countable wave", than either or both a wave and/or particle.
Any distribution of light can be broken down into a set of modes (wave-like functions that extend over space), inside of which live a (potentially rather complicated) set of mixtures and/or superpositions of countable excitations.
that this sort of cancellation idea is easy with sound, because sound is much slower than the electronics used to generate the cancelling signal; the slight lag can be made undetectable.
... because you need to know everything about the incoming beam before it gets to you; so either you have to have a conspiracy or have to violate causality:
If you don't like the embargo system, don't cooperate with it. Just find the story out yourself ahead of time, rather than being spoon fed by the editors and PR people. Spoon fed? Or did I mean conveniently pre-filtered work of potentially wide interest?
A certain spacetime cloak story went out under embargo, for instance. But, had you been looking, you could have found information on conference presentations of the work made well beforehand; and followed it up yourself. Likewise for many science stories that make it into the press, I would think.
Finally- these are science stories, not ones about corruption, criminality, fraud, etc. It doesn't matter that much whether we hear them on a Tuesday or a Wednesday. And it gives the reporter time to not mangle the story quite as much (perhaps even - gasp - checking the write up with the authors) before it hits the newsstands.
We can tell the difference between what we assumed, and what we use as an analogy to get the basic concept of the event cloak across to the interested reader.
For the record, I never liked the "transporter" analogy, since at best it only gives the appearance of instantaneous transport. But this device _is_ a cloak.
Rather pleased to see my crap anim in the Reg. :-) And for the full chicken analogy, see http://www.qols.ph.ic.ac.uk/~kinsle/files/STcloak/
Regarding "already at the speed of light" above, you have to embed the cloak in a non-vacuum medium -- so you can both slow down from average-speed, and speed up to above average speed (max the vac. speed of light),
... I recall, as a pre-boffin, helping (in some appropriately minimal way) to set up the janzos cosmic ray telescope on Black Birch, which was designed to look at sn1987a. I recall that it was quite cold and I carried some moderately heavy things about while others did the real work. Not much of a claim to fame, admittedly :-)
"one person’s terrorist is another person’s freedom fighter"
I have always found this an annoyingly sloppy statement, which confuses two distinct concepts: Methods and aims are not the same thing!
Specifically, "terrorist" refers to methods used, "freedom fighter" refers to political aims.
A freedom fighter might (or might not) choose to use terrorism as a means to achieve freedom for their chosen constituency. Likewise, a group of repressive fascists might use terror to achieve their aim of a totalitarian state. Then again, they might sneakily use cleverly arranged and predominantly peaceful demonstrations.
Numerous Earth-destroying doomsday scenarios have recently been analyzed, including breakdown of a metastable vacuum state and planetary destruction triggered by a "strangelet” or microscopic black hole. We point out that many previous bounds on their frequency give a false sense of security ...
"An accelerometer means the screen auto-rotates as you turn the Opus in your hand, and we think this is a feature other manufacturers should take a note of"?
... except if you want to look at a sideways printed table (sideways, because it's too wide to fit sensibly in portrait). Then auto-rotate'd just be bloody annoying.
Shawler claims an _improvement_ over ordinary light pressure -- by the Q factor of the cavity! Naturally if Q is high, you get more supposed "Shawler thrust", ... but high Q means that hardly any light escapes to provide actual thrust. The force exerted will in fact reduce as Q increases.
note that "controversial" has not the same status as
"violates the conservation of momentum"
Existing "standard" physics states clearly that this device cannot work. But, curiously, the theoretical arguments advanced by Shawyer, don't include any new physics, just a somewhat confused calculation based on standard physics. Anyone want to spot the contradiction?
And, quite frankly, if you are going head-to-head against conservation of momentum and Einstein's theory of relativity, then you have to perform better than that video. What was it? Box hanging from a wire swings and/or rotates slowly?
para 4: "The announcement will give cheer to the research community which has been angered by a recent claw-back of £98m in funding to cover cost overruns at the DTI (Department of Trade and Industry)."
... is most likely one of the things a race of intelligent and technologically adept seals would be likely to do, eventually. Before they try to put one in orbit. Etc.
Perhaps it's an apology on the behalf of the British State, which most certainly was in existence at the time. After all, he is the Prime Minister, and therefore is an appropriate representative of the State. I guess the Queen could also function as an appropriate apologee.
they could repackage their product as an application for users to install on their own computer, and which makes recommendations to that user. If it was useful, it might sell.
Do I need a semi-intelligent recommendation agent? Sort of a web version of http://www.remem.org/ ? Hmm...
I agree totally with your points about how plants are conveniently self-replicating, scalability, cost/watt etc.
But trees are not free (whether to manage, use, or bury), so the enormous difference in efficiency _might_ allow scope for a useful mass produced PV->carbon-fuel system. Especially since growing trees in the desert can be non-trivial -- but there is lots of solar energy.
Trees (and indeed plants in general) are remarkably inefficient at converting CO2 into carbon. What we need are photo-electric CO2-> Carbon converters, since photoelectric tech is orders of magnitude more efficient at extracting solar energy than plant photosynthesis.
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105 posts • joined Thursday 9th August 2007 10:42 GMT
Page:
Re: The results from 6 birds ...
I'm sure they'd be happy for you to fund a bigger, follow-on study once they've got the practicalities worked out and tested on this one.
Re: Isn't there a problem with this?
Haven't read the paper, but perhaps they mean they move the dopants out of the way of the (desired) electron trajectories; whilst leaving them sufficiently nearby so as to leave other properties unchanged.
Coffee Mugs ...
... anyone know where I can buy one with the right slot for a Kensington Lock?
Also on coffee boffinry:
http://physics.aps.org/synopsis-for/print/10.1103/PhysRevE.85.046117
http://physics.aps.org/synopsis-for/10.1103/PhysRevE.85.046117
Re: FTL?
Briefly: something that appears to be information-like gets transmitted faster than light; but, whatever it is, it is of no use to you at all - until you have the chance to correlate it with some ordinary information sent to you in an ordinary (light-speed-limited) way.
Re: What about copyright?
If your research grant mandates open access in a manner incompatible with (eg) Elsevier's conditions, then you should not publish results funded by that grant in an Elsevier journal.
what you (might) have to pay
Examples from the physical sciences
New. J. Phys. -- mandatory article fee £650 (but £550 for IoP members) (www.njp.org)
APS journals: (http://publish.aps.org/)
Phys Rev -- open access fee $1700
Phys Rev Lett -- open access fee $2700
OSA journals: (http://www.opticsinfobase.org/)
Opt. Express -- mandatory fee $1018 for 6 or fewer published pages
JOSA, etc -- open access fee $1500
Re: "Academic" publishing?
"Its content is written by its own flacks" - true of news content, not of their feature articles, usually/often written by the scientists concerned (I co-wrote one on spacetime cloaks last year).
As regards embargoes, they work in that (as far as I can tell) you get a much better hit and a wider spread of publicity than if the story leaks out slowly from various sources. And it is only science news, does it really matter if you hear about that new superconductor/whatever a week later? If it does, then you shouldn't be relying on the news media!
You could, for example, follow journal RSS feeds and the arxiv, and pick up newsworthy science off your own bat without being slaved to press releases and news magazines. You might cultivate a set of scientists and ask them to pass along any interesting stories for you to take a reporter's look at. If so, you might find more diverse set of science stories appearing, not just the latest angle from some boffins who've managed to reference not only Harry Potter, but also Star Trek and safe-cracking bank robbers in their Press Release.
it's a time lens
and a rather approximate diagram in a sort of co-moving (time) frame of reference. Bending back (down) is a relative slowing.
The point is you use the concept, not a specific (optical) implementation.
For example you imagine that by speeding and slowing the clock signal of a target system you can preserve its outputs unchanged from the unaffected case, but nevertheless create a time interval in which you can use the hardware undetected. But at the moment this is just a concept, not a suggested implementation.
Axel Rose is right
The point of a cloak - whether spatial or spacetime is not just to hide things or events, but to also hide the fact that they are hidden.
But rather than "Cornell method", I think you might mean "Imperial College London method" instead :-)
Some other links & commentary (by me)
http://www.citeulike.org/blog/pak/16541
http://www.qols.ph.ic.ac.uk/~kinsle/files/STcloak/
there are two obvious interesting things going on
(i) the rhetorical battle between the pro- and anti- AGW camps,
(ii) the progress being made in scientific understanding of the climate.
Not sure what the emails will tell me much about either of those.
nb:
"Still, the Riess et al and Perlmutter papers were persuasive direct observational evidence"
And this is what counts: the Nobel Prizes (at least in Physics) /tend/ to be awarded for practical and/or experimental results, rather than theoretical breakthroughs or concepts.
re: (wheel) Maxwell's equations are relativistic?
Perhaps remarkably, Maxwell's equations indeed are relativistic, and were so before SR was proposed by Einstein. If you want a plausibilty argument, then consider that SR uses light(speed) propagation to establish a metric, and that Maxwell's equations describe light propagation.
Otherwise, I suggest you go read any EM textbook.
Or ponder why, post-SR, Maxwell's equations are so popular.
Or feel free to invent a theory of non-relativistic light to describe your laser. Good luck with that, eh.
lasers depend on relativity
well, since lasers produce light, and light follows Maxwell's equations, and Maxwell's equations are relativistic ...
It's a sign of the incipient Singularity ...
but no, not the "technology" Singularity.
This is the one Singularity that's actually going to happen: The Bubble Singularity, where bubbles of all kinds -- financial, technical, cultural -- arrive faster and bigger and more destructive, all the way to Infinity.
I, for one, welcome our Frothily Singular new overlords, all Infinity of them.
the advantage of squeezed light
is not really the reduced uncertainty, but one of reduced power - which then minimises error, as (crudely) less photons bounce of the mirrors, so the mirrors wobble less.
This is because to create squeezed light requires a high-power beam to be converted into a lower-power squeezed beam. And the phase uncertainty in the raw unsqueezed beam (required to create a phase-squeezed beam) is about the same as that in the lower-power squeezed beam.
So An Airy Beam Is A... wavelet
No, it isn't. True Airy beams are very non-local, and in fact (crudely speaking) the reason they don't diffract is that they're already spread out enough (and in the right way) so that the light diffracting out from the middle of the beam is exactly balanced by the light diffracting back from the edges.
A wavelet is a localised mathematical object, useful as a basis with which to describe similarly local, oscilliatory thing - e.g. light beams or pulses.
You could describe arbitrary beams in terms of a basis of "Airy modes", but the Airy functions aren't local enough to match with the wavelet concept.
Specifically: if the acceleration vector is (& stays) perpendicular
to the velocity vector, the object will change direction but not speed.
nope
Superlenses rely on amplifying & controlling the (non-propagating) evanescent excitations; phases arrays control propagating waves. Use of propagating (and typically sinusoidal) waves doesn't eneble as tight a focus as the much better localized (typically exponentially decaying) evanescent components.
nah - it's an explorobot ....
http://www.qols.ph.ic.ac.uk/~kinsle/files/b3/11/spirit-alt.png
light
is more of a "countable wave", than either or both a wave and/or particle.
Any distribution of light can be broken down into a set of modes (wave-like functions that extend over space), inside of which live a (potentially rather complicated) set of mixtures and/or superpositions of countable excitations.
Note
that this sort of cancellation idea is easy with sound, because sound is much slower than the electronics used to generate the cancelling signal; the slight lag can be made undetectable.
Light, however, is not slow.
Will not work in any useful sense ...
... because you need to know everything about the incoming beam before it gets to you; so either you have to have a conspiracy or have to violate causality:
See:
"Active drains and causality",
P. Kinsler, Phys. Rev. A82, 055804 (2010),
or
http://arxiv.org/abs/1008.2088
embargoes
If you don't like the embargo system, don't cooperate with it. Just find the story out yourself ahead of time, rather than being spoon fed by the editors and PR people. Spoon fed? Or did I mean conveniently pre-filtered work of potentially wide interest?
A certain spacetime cloak story went out under embargo, for instance. But, had you been looking, you could have found information on conference presentations of the work made well beforehand; and followed it up yourself. Likewise for many science stories that make it into the press, I would think.
Finally- these are science stories, not ones about corruption, criminality, fraud, etc. It doesn't matter that much whether we hear them on a Tuesday or a Wednesday. And it gives the reporter time to not mangle the story quite as much (perhaps even - gasp - checking the write up with the authors) before it hits the newsstands.
I think maybe
We can tell the difference between what we assumed, and what we use as an analogy to get the basic concept of the event cloak across to the interested reader.
mind you,
although I said I above that I never liked the ST transporter analogy ... it does seem to have attracted the attention.
"is a cloak"
I see what LP meant now. He meant flappy garment favoured of vampires, not the more technical "electromagnetic cloak"
no titles for me
For the record, I never liked the "transporter" analogy, since at best it only gives the appearance of instantaneous transport. But this device _is_ a cloak.
Rather pleased to see my crap anim in the Reg. :-) And for the full chicken analogy, see http://www.qols.ph.ic.ac.uk/~kinsle/files/STcloak/
Regarding "already at the speed of light" above, you have to embed the cloak in a non-vacuum medium -- so you can both slow down from average-speed, and speed up to above average speed (max the vac. speed of light),
yep
and just give them *.wales.uk to play with.
perhaps
they are USB femtocells :-)
sn1987a?
... I recall, as a pre-boffin, helping (in some appropriately minimal way) to set up the janzos cosmic ray telescope on Black Birch, which was designed to look at sn1987a. I recall that it was quite cold and I carried some moderately heavy things about while others did the real work. Not much of a claim to fame, admittedly :-)
"one person’s terrorist is another person’s freedom fighter"
I have always found this an annoyingly sloppy statement, which confuses two distinct concepts: Methods and aims are not the same thing!
Specifically, "terrorist" refers to methods used, "freedom fighter" refers to political aims.
A freedom fighter might (or might not) choose to use terrorism as a means to achieve freedom for their chosen constituency. Likewise, a group of repressive fascists might use terror to achieve their aim of a totalitarian state. Then again, they might sneakily use cleverly arranged and predominantly peaceful demonstrations.
Methods and aims are not the same thing.
I'd quite like to see a climate science debate...
that discussed the issues rationally ... but wait: apparently that simply won't work...
http://arxiv.org/abs/1004.5009
Either lie, or lose the battle for public opinion. Choose your preferred option carefully now ...
How unlikely is a doomsday catastrophe?
http://arxiv.org/abs/astro-ph/0512204
Abstract
Numerous Earth-destroying doomsday scenarios have recently been analyzed, including breakdown of a metastable vacuum state and planetary destruction triggered by a "strangelet” or microscopic black hole. We point out that many previous bounds on their frequency give a false sense of security ...
auto-rotate
"An accelerometer means the screen auto-rotates as you turn the Opus in your hand, and we think this is a feature other manufacturers should take a note of"?
... except if you want to look at a sideways printed table (sideways, because it's too wide to fit sensibly in portrait). Then auto-rotate'd just be bloody annoying.
Re: Laser beam powered space craft
Shawler claims an _improvement_ over ordinary light pressure -- by the Q factor of the cavity! Naturally if Q is high, you get more supposed "Shawler thrust", ... but high Q means that hardly any light escapes to provide actual thrust. The force exerted will in fact reduce as Q increases.
note that "controversial" has not the same status as
"violates the conservation of momentum"
Existing "standard" physics states clearly that this device cannot work. But, curiously, the theoretical arguments advanced by Shawyer, don't include any new physics, just a somewhat confused calculation based on standard physics. Anyone want to spot the contradiction?
And, quite frankly, if you are going head-to-head against conservation of momentum and Einstein's theory of relativity, then you have to perform better than that video. What was it? Box hanging from a wire swings and/or rotates slowly?
""There’s no way of signaling that it’s a parody." (on a computer)
... except perhaps by adding some text saying "this is a parody" somewhere not too inconspicuous. Or is there a <parody> tag?
ahem
"football fields" = a unit of area
350m = in units of length
... and presumably the size of the asteroid is actually best expressed as either a volume or a mass.
Confused?
ringfenced? bollocks, see
see: http://news.bbc.co.uk/1/hi/sci/tech/6475801.stm
para 4: "The announcement will give cheer to the research community which has been angered by a recent claw-back of £98m in funding to cover cost overruns at the DTI (Department of Trade and Industry)."
Exploring the Himalayas with seals ...
... is most likely one of the things a race of intelligent and technologically adept seals would be likely to do, eventually. Before they try to put one in orbit. Etc.
Re: Cringeworthy
Perhaps it's an apology on the behalf of the British State, which most certainly was in existence at the time. After all, he is the Prime Minister, and therefore is an appropriate representative of the State. I guess the Queen could also function as an appropriate apologee.
public policy could itself become the captive of a scientific-technological elite
"That capture is now complete - scientific "study" merely serves the political fashion"
Wrong! -- that's the scientific-technological elite becoming the slave of public policy.
Perhaps
they could repackage their product as an application for users to install on their own computer, and which makes recommendations to that user. If it was useful, it might sell.
Do I need a semi-intelligent recommendation agent? Sort of a web version of http://www.remem.org/ ? Hmm...
Re: Run on the bank?
> It's virtual currency
Even the money in your wallet is virtual.
keep the battery sensor and add a dialog:
"This is not an approved Panasonic battery, and may be unsafe. Continue Y/N?"
Or put sensors in that detect and/or mediate battery malfunction; maybe with
an audible overheating alarm.
I for one...
.. plan to be puzzled by the forthcoming tribe of escalator-step-spotters, each one carrying their portable rfid reader.
But just think if I had an rfid reader in my shoes! The escalator journey tracking info I could automatically collect!
hmm
So maybe I should campaign for the copyright on my physics research papers to be returned to me after 50 years.
@ M Burns etal
I agree totally with your points about how plants are conveniently self-replicating, scalability, cost/watt etc.
But trees are not free (whether to manage, use, or bury), so the enormous difference in efficiency _might_ allow scope for a useful mass produced PV->carbon-fuel system. Especially since growing trees in the desert can be non-trivial -- but there is lots of solar energy.
@soylent trees
Trees (and indeed plants in general) are remarkably inefficient at converting CO2 into carbon. What we need are photo-electric CO2-> Carbon converters, since photoelectric tech is orders of magnitude more efficient at extracting solar energy than plant photosynthesis.
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