A step closer to ylem?

[Cray]

http://www.bbc.com/news/science-environment-27470034

[stevebowers]

The technique involves hitting a cloud of x-rays with a beam of gamma-rays inside a tiny gold hohlraum. Sounds like the method proposed for antimatter creation in an amat farm.

Surely this method would create just as much antimatter as matter- which could be a useful feature.

[Ithuriel]

Isn't it "just" a way of inducing pair production? You're only getting electrons and positrons out of the other end... useful, to be sure, but it isn't like they've found a way to conjure up hadrons from nothing.

[terrafamilia]

The technique involves hitting a cloud of x-rays with a beam of gamma-rays inside a tiny gold hohlraum. Sounds like the method proposed for antimatter creation in an amat farm.

Surely this method would create just as much antimatter as matter- which could be a useful feature.

Question from those of us in the physics for liberal arts majors crowd. What is a "cloud" of photons?

Ciao,

Terrafamilia

[Cray]

Question from those of us in the physics for liberal arts majors crowd. What is a "cloud" of photons?

Something like this I suspect, though I'll have to wait for the physics heavyweights to weigh in.







I'd guess a "cloud of photons" is a space where photons are constantly be transmitted or sprayed. A continuous beam of light, in other words. Instead of calling it a "ray" or a "beam," they're describing it as a "cloud" of photons to make the point that something being shot through the beam will almost certainly bump into one of the ray's photons because that volume is always filled with photons, even if the photons aren't just floating around like fog particles in a cloud.

[omega_tyrant]

A poster mentioned earlier that this experiment only shows that light can be turned into electron positron pairs. In principle, could it also be possible to coax hadrons out of these reactions, if say, higher energies were used? Or is the whole idea just impossible?

[stevebowers]

Well, the idea behind the antimatter farm concept is that protons and and antiprotons can be created using intersecting beams of finely tuned particles;
http://www.orionsarm.com/eg-article/45f0c79d13c29
the idea comes from the paper referenced at the bottom of that page
http://arxiv.org/abs/physics/0507125
which includes this image

[stevebowers]

My version of this mechanism is here

I've passed over the extreme technical difficulties of such an arrangement without comment in the article concerned - such a high-energy collider would presumably also produce a large number of unwanted and highly energetic species as well, so it seems unlikely that there would be any bionts on board. The beams used in these colliders aren't photons, however.

[omega_tyrant]

Sorry to bring this thread back from the dead, but I've been thinking about the implications of turning light into matter, and how that might be useful in the far future in "Deep Time." I've been reading about the Heat Death of the Universe, and how all matter will eventually decay into photons and leptons, and no more useful work will be possible in the universe after this time. If photons can be turned into quarks and other types of matter, theoretically, shouldn't this delay the "Heat Death" scenario at least somewhat? Wouldn't those newly created bits of matter be able to do useful work? Perhaps my understanding of "waste heat" is not complete. What does waste heat consist of? If it is just photons, then shouldn't they be able to be re-used under this hypothetical case?

[stevebowers]

Manufacturing matter from photons is a form of work, which increases the entropy of the universe, thanks to thrmodynamics. You can manufacture a few electrons and positrons et cetera from ambient light, but every time you do the heat death gets even closer. On the other hand it must be easier to do processing with matter than with photons by themselves.