Physicists create light out of nothing
abc.net.au
abc.net.au
That said, they didn't create light out of nothing, they created light out of the vacuum. The vacuum is something - at least its fluctuations are, so they didn't create light out of nothing.
'it means just what I choose it to mean — neither more nor less.
"hand vacuum pump (the one that you can use to bleed brakes with) and hook up the line directly to the actuator and put vacuum in it"
"I was wondering if anyone has experimented with a vacuum pump or any other way to put vacuum in the crankcase."
"I believe VW uses an air pump to test the evap system instead of relying on engine vacuum to put vacuum in the evap system"
"I want to be able to put vacuum in and leave it but not sure why no suction?"
It seems that many people regard it as having a concrete meaning. (I saw little hit of a non-concrete meaning. The other cases I saw were things like "put vacuum in pool", in reference to a vacuum cleaner.)
There were 138 non-duplicate matches for "put darkness in". All were metaphorical, and most were due to a Biblical verse.
While there are some references to "put cold in", as in:
"If you put cold in the thermostat doesn't kick on until much later causing the water to freeze at a later time."
"it's identical to a regular hotwater tank so you have to put cold in to the drain and loop it back"
they are short-hand for "cold water". Otherwise the terms are either metaphorical, like "put cold in its place with this warm parka", or a reminder that chilling devices don't put cold in but rather take heat out.
The phrase "put dry in" only appears in context like "Get 2 [dog] bowls and put dry in 1", or "I didn't have fresh basil so I put dry in the mayo", where the "dry" refers to a preceding noun. (The one exception was the question "why would they want to put dry in their beer?".)
Thus, a haphazard search of the Google corpus reinforces my assertion that putting vacuum in (something) has a more real, concrete sense than putting darkness, cold, or dry in (something).
... uh, sorry, I got carried away.
We can go on discussing about how painting is about adding to a canvas, while sculpting is about taking away the parts you don't need.
Such discussions are pointless.
So it's kinda a poorly written article in general :)
This often means no matter how good the writers understanding is of the subject, the headers always make the article look retarded. It would be like assigning a 12 year old to subheader Stephen Hawkings next book... the sad thing being the 12 year old would likely do a better job than the 40 year old who does this for their living.
While the static Casimir effect does this in the three dimensions of space, the dynamical Casimir effect does it in the dimension of time.
WTF!? This is the last line of the article. That's the most interesting line in the whole thing, and it's totally unexplained and left hanging. What's with the authors/editors? Science journalism is such fluff, that it's no longer about interesting ideas, but contentless amazing sounding word salad.
What differs in these effects (in space and in time) is the electromagnetic modes of the vacuum near the mirror(s).
http://en.wikipedia.org/wiki/Normal_mode#Quantum_mechanics
It's all about creating a differential - and the effect this has for static vs. dynamic is different for each.
In the static effect, a differential is created in 3d space: two mirrors are perfectly placed in parallel to each other with a gap less than that of a photon's wavelength. In the vacuum fluctuation of space, virtual photons and anti-photon pairs are created and annihilate each other all the time - but this tiny gap keeps them from appearing between the mirrors. The end result is a difference in the modes between the mirrors (total lack of any activity) and outside them (normal vacuum fluctuations) which results in a pressure differential (in 3d space) pushing the plates together (the static effect).
In the dynamic effect, a differential is created due to a change over time: a mirror is moved at a velocity significantly close to the speed of light (in this case, around 5%). Around the mirror, as always, the vacuum contains photon and anti-photon pairs coming into existence and annihilating each other. With a fast enough moving mirror, the mirror can change the ability of the particles to annihilate each other. This represents a change in time over the nature of the vacuum / space where the particles appear.
Thought example: Prior to pair formation, there is no mirror at coordinate XYZ. Proton and anti-proton pair appears - and mirror is moving so fast, it is now present at point XYZ, between the proton and anti-proton, faster than the two could reach and annihilate each other. Now, instead of annihilation, the proton is reflected by the mirror.
This is the dynamical Casimir effect. It is a change, over time, in the nature of vacuum.
Yes, photons are being reflected ("created from nothing") in this effect - but so are anti-photons, which quickly find some other photon to interact with and annihilates the pair of them. There is no net gain of energy here - in fact quite a bit is spent keeping the mirror moving at high speeds.
When you say the virtual particles are reflected, but quickly find another pair and annihilate each other, are they pairing wth normal photons? And because of the lack of anti-particles in our universe, isn't it more difficult for the photons to pair, meaning that if this experiment was scaled exponentially, the virtual photons would have an increasingly harder time pairing, becoming more abundant and living longer?
There is no such thing as an anti-photon, and if there was, then a photon anti-photon pair would annihilate to produce - more photons!
Time in the quantum world is not completely logical, essentially these virtual particles (they are not real particles!!) can not appear unless they already managed to annihilate and vanish (i.e. the order of operations is not one way).
The reason these photons do manage to exist is that the experiment provided the energy necessary before the particles appeared. The "anti-photon" is not a real particle, and does not need to find another photon to annihilate with. It's more of a concept of energy, what it represents is missing energy, which needs to be provided in order for the partner (the regular photon to exist).
The "missing/extra" energy pair can exist only for a short time, below the Heisenberg uncertainty limit. If, in some way, you disrupt the annihilation of missing and extra energy, the particles would not appear in the first place (that's that out of order business I was talking about). But since the experiment provided energy, the particles can appear, and then be split, and the "anti-photon" uses the energy of the experiment to not exist.
You have probably heard of the momentum/location uncertainty pair - but there is another: it's time/energy. So the more exactly you know how much energy there is, the less you know about when it existed - that's why the particle can have this out of order behavior - time itself is not properly defined for it.
Though the underlying science is very interesting, I wish we could have less sensationalized coverage. Nothing under this section title involves going faster than light.
You need to get people to read. There's no point in having a fantastic finish if no one gets there.
About the article, I think the phenomenon itself is amazing. The Casimir effect is remarkable enough - completely at odds with classical physics and yet trivally predicted by quantum physics, it's a great piece of evidence for how weird the world is. To see it demonstrated using time as one of the dimensions is brilliant.
OTOH, sp332 seems to have found the same story from another source, and in the discussion there people are suggesting that the quantum explanation is out of place and/or unnecessary, because it's more-or-less just like an antenna. http://news.ycombinator.com/item?id=3511341
Then people just pick holes in the writing. I find that sad.
With that said, can you provide more of an intuition for the Casimir effect? Specifically, a better intuition for why is there are less fluctuations between two plates than outside of them? Is it simply because there's so little space between the plates, and hence less space for fluctuations? The wikipedia article doesn't really provide this level of intuition.
When playing a bugle, high notes are all close together in pitch because with short wavelength, adding one makes a proportionally small change. Playing lower notes, the notes are further apart - there are effectively fewer notes in the lower ranges because adding one extra wavelength makes a big difference to the pitch.
Similarly the wavelengths of particles between the plates. When the plates are far apart, pretty much every wavelength can appear between them, so things are the same inside as out. When the plates are close together, fewer particles/waves can appear between because their wavelength must divide the distance, while the ones outside are still unrestricted. Then there are simply more of them, resulting in a higher pressure.
> the spooky properties of quantum physics
Can we link to the actual research papers from now on? Pretty please? With sprinkles on top?
The reporter is probably referencing that to some extent but mainly in the sense that it goes against classical intuition.
No, in practical terms that's impossible because the mass of the mirror would become unfathomable when it got within 10% of the upper speed of light.