Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 internet speed test! ×

Comment Re:Worthless BBC article (Score 2) 105

Skip the BBC article and go straight to the arXiv preprint.
Quote from the abstract:

Our results for one particular benchmark do not rule out the possibility of speedup for other classes of problems and illustrate that quantum speedup is elusive and can depend on the question posed.

The study asks a very specific question and acknowledge its limited scope.

Comment Re:Preventive tech? (Score 1) 76

Imaging through scattering media, for noble causes such as medical imaging, is a current and productive research area in optics. You can account for essentially arbitrary scattering as long as it doesn't change quickly. While the technology would be different, but I expect that the mathematics and the techniques already exist to thwart and such wall which you might design.

On the other hand, a 5mm sheet of aluminium ought to do the trick. :)

Comment Re:Yes, but... (Score 1) 139

Did aluminium really catch fire on HMS Sheffield? It seems to be well known that it did, but is it true? Aluminium Design and Construction by John Dwight, Section 1.1.7 refutes the assertion:

Three of the British warships sunk in the Falklands war ... had aluminium superstructures. At the time, the press stated that ... the aluminium had actually burnt. This was completely untrue. The aluminium structures lost strength and distorted, but did not burn. Aluminium sections, plate, sheet, foil and wire will not support combustion. Only in the form of very finely divided powder or flake can the metal be made to burn, as can finely divided steel.

Comment Re:Transporters (Score 1) 383

I'm not quite sure how Star Trek handled the concept, but in reality the No cloning theorem of quantum mechanics tells us that, while teleportation is possible, you can never have two copies at the same time. Teleportation, used in this sense, is implemented by transferring all the information necessary to make a perfect copy of the original state; no cloning theorem tells us that this must destroy the original. And perfect really does mean perfect; the copy will be indistinguishable from the original. Such indistinguishability is a crucial part of quantum mechanics; it leads, for example, to the Pauli exclusion principle.

Comment Re:Let's not jump the gun. (Score 1) 250

I suppose I mean that, from my perspective, I have all the functions that Aero would provide. If I so chose, this could include streaming to multiple users since several mythfrontend instances can talk simultaneously to the backend over a network. I do note the difference, however, in Aero being run by a company, not by the user.

Comment Re:Eventually... (Score 1) 169

Citation for the parent: http://www.sciencemag.org/content/329/5999/

n.b. the work [1] by Müller, Chu et al is related, but different, and the interpretation is strongly contested (e.g. [2])
[1] http://newscenter.berkeley.edu/2010/02/17/gravitational_redshift/
[2] http://www.nature.com/nature/journal/v467/n7311/full/nature09340.html

Comment Re:How do you measure how accurate it is? (Score 2) 169

1) You make two and see by how much they differ after a certain time. (Further reading, see Allan variance.)
2) As with all the base units, we must 'define' the second in terms of something physical, which we can measure, so that we can use this abstract idea in the real world. This real-world embodiment is imperfect, and it is an engineering challenge to make something which better approximates the idea. For illustration, consider the kilogram, which is defined by a lump of metal in Paris. In principle, chipping a bit off this block makes everything else weigh more in terms of kilograms, but we immediate recognise this as crazy and we can imagine a better physical embodiment of the ideal kilogram (indeed, efforts are under way to do just this). So it is with the second: the caesium clock is the best we've got so far, but it's just a physical embodiment of the ideal second, and we can strive to make a more accurate (with accuracy defined as in (1) above).

Slashdot Top Deals