Whats the matter?
What exactly are the photons being transmuted into? Atomic particles like electrons? Sub-atomic like quarks etc?
A trio of theoretical physicists reckon scientists will be able to make matter out of pure light* within the next year using today's technology. The photon-photon collider that could prove the Breit-Wheeler theory of how to turn light into matter The idea of making matter out of light sounds far-fetched, but it’s an …
That the product is an electron/positron pair suggests to me that rather than converting the photons into e-/e+ pairs, it could be that it's interacting with a virtual e-/e+ pair and giving them enough energy to overcome their attractive nature, so instead of instantly annihilating again, they fly off on separate paths, having absorbed the photon(s), a sort of analogue to Hawking Radiation. Be interesting to see the outcome of this experiment. And I wonder if there are similar interactions that thoeretically exists, or if it's only photons->e-/e+ - ie could sufficiently energetic photons produce muon/anti-muon pairs?
Well, kinda. In QFT terms, fluctuations in the electron-positron field would be stabilised into quantised waves by the energy of the photons. QFT people tend to dislike "virtual particles" as confusing.
If the photons are energetic enough, then any particle/anti-particle pair can be formed; it's just that e-/e+ pairs are the lowest energy by miles, and really high-energy photons are a pain in the arse to deal with, which is why the experiment is so tricky.
You could get proton/anti-proton if you have 1870 times the energy in your ɣ/ɣ collision compared to the electron-positron pair. But getting 1870 times the energy, now there's the rub.
Why not start with up and down quarks and let the protons build themselves (and the anti particles of course)? Third of the energy expenditure or so. Take it that the 1870 times energy rate is for whole proton and not just a quark?
Wouldn't you need a large magnetic field to keep the anti-matter and normal stuff apart so it does not reconvert to gamma pretty smartish, which would stop proton formation but could give you some mesons?
I don't think the process will result in pairs that would produce muon/anti-muons...It seems they are suggesting the convergence will produce a dipole or single lepton, i.e. electron
It seems unlikely the collision could reach the mass of a a muon in such an experiment with considerable mass; considering the energy from such a collision doesn't seem to have enough power to create muons.
e does = mc2 so where super density is not present, a lepton being formed is dependent of angular momentum or spin of the electron formed...
I am skeptical they will actually even produce an electron and if it produces anything at all it may produce Neutrinos...
Guess we'll have to wait and see...
"Demonstrating the Breit-Wheeler theory would be the final piece of research needed to describe the simplest ways light and matter interact and help to solve one of physics’ greatest mysteries - gamma ray bursts, THE BIGGEST EXPLOSIONS IN THE UNIVERSE."
-- has anyone stopped to think that this experiment might be a BAD IDEA??
When GRBs were first discovered, I couldn't help noticing that the energy patterns represented what I felt would be produced by an object breaking the light barrier. Yeah yeah yeah only light travels at the speed of light - but we know that that is true only for a given value of true. If something were to go transluminary, there would be a massive energy surge at the point where the status change occurred.
Consider the energy release pattern at the point where an object passes through the 'sound barrier' and contextualising it in the transluminary context, and we have a similarity which needs consideration. If there were to be small clusters of GRBs found eventually, that could signify intelligent traffic and be an indicator of interstellar trade.
The only downside of a replicator based on this mechanism is the formation of an anti-hamburger together with your hamburger. It may be a balanced diet, in a manner of speaking, but could lead to explosive indigestion to which the phrase "blast radius" would seem to small (swamp dragons would be jealous)
<see title - when they get it to work presumably>
The photon generating technology could also be applied to car headlights, because we all know that up-market sport-saloons need really, really, really bright (often misaligned), headlights so they can dazzle every other driver in the on-coming stream for miles.
GOLD because it is nice and dense, nearly twice the density of lead, and not radioactive.
There's not much thats denser than gold (SG=19.3). Osmium (SG=22.6) is the densest easily available substance and costs a lot more than gold ($77000/kg vs $27000/kg), which seems like a lot to pay for a 15% density increase. Density is important in this experiment: the denser the target, the more likely that the electrons in the beam are to hit a nucleus in that target and hence the stronger the resulting gamma ray beam. The most commonly available bulk radioactive, Uranium, is less dense than gold and half the price, but it seems likely that its radioactivity could screw up the experiment as well as making it nasty to handle or store.
I would have thought if density was the driving requirement and that given they, supposedly, only use a very thin leaf of the metal that getting that extra 15% and the extra intensity that goes with it would be worth the expense.
Of course for all I know a 15% increase in density will only lead to a 0.1% increase in collisions but I'd hate to think an expensive experiment like that was cutting corners with a hundred quids worth of thin metal.
Physical properties. Amongst others it's highly reflective, highly malleable, polishes to a near-perfect mirror surface, conducts electricity very well, doesn't tarnish(*), and it's very dense.
(*) More accurately it's a noble metal - a gold surface is actually gold. C.f. aluminium or zirconium or many other shiny metals which also polish to a good mirror, but which have surfaces of protective metal oxide, not pure metal.
Here I guess that the high density is key for the target. Platinum is slightly denser but won't offer such a clean surface, is harder to fabricate, and costs even more in any case.
A gold+research lab story.
Some years ago, I heard a story about how a company resolutely insisted on wasting the not insignificant cost of about three ounces of gold.
One of the many research uses for gold is vacuum deposition onto objects prior to scanning electron microscopy. The gold blank in the heavily used gold plater had finally been used up. (Most of it deposits on the bell jar that maintains the vacuum, and then gets washed down the sink a few milligrammes at a time, because you don't want a shiny gold opaque bell jar, you want a transparent one.)
A replacement gold blank made of ultrapure 99.999 gold cost several times the gold content. The cheap approach was a Krugerrand, which happened to be the same diameter. Of course it's less pure gold, but that didn't matter.
But could these guys get an order for a Krugerrand past purchasing? To cut a long story short, no, No, NO!!. Expensive ultrapure overpriced gold blank it had to be. Laboratory equipment suppliers good. Bullion dealers bad.
So, if they create matter are they also creating anti-matter somewhere?
Isn't there a chance of:
An explosion that kills us all/sends us to a parallel universe/makes a black hole ?
Unexpected anti-matter appearing and killing Angels/Unicorns ?
Rapid enchancement of global warming due to (whatever can be thought up on the spur of the moment)?
Yup, the article talks about electron-positron pairs. The positrons would be the anti-matter bits.
So, to add to your fine list: possibility of making a hole to another dimension from which robots with positronic brains emerge. No matter what orders we shout at them, they shut down the facility, because it is dangerous to poor befuddled humans.
There's a rarely-considered particle that is created by all high-energy physics experiments. They violate causality, because they always appear before the experiment is carried out, and never afterwards.
They're called Trolls.
I beleive the origin of 'trolling' is that of a method of fishing where something shiny is dragged through the water to see what gets hooked.
Fortunately, the tin-foil hats on sale are also perfect material for tying on the end of a line.
Trolling and trawling are very different ways of fishing. Even Shirley kno that.
Trolling is, as described, towing something at the end of a fishing line that should look tasty to a fish. Its often shiny or brightly coloured but can also be made from feathers that undulate as they're towed. Trolling is ecologically sound because it doesn't cause collateral damage.
Trawling is dragging a huge netting bag, with a heavy frame to keep its mouth open, along the seabed behind a fishing boat. This rips up and destroys all the corals, seaweed, etc in its path and traps all the fish that don't swim out of the way fast enough. Apart from causing seabed damage, the trawl scoops up and kills a lot of unwanted types of fish which are dumped overboard. Its not even a remotely sound activity from an ecological viewpoint: fish farming is better.
Well, the theory is quite well established. It'd be nice to see an experiment prove or disprove the theory.
Of course, many an experiment that had an "Hm, now *that* is funny" has lead to major breakthroughs in science and technology, some of which we're benefiting right now from.
Just as some complain about the cost (apparently, anyone with money must spend that money the way commentards decree it), forgetting that that "pie in the sky" science has resulted in the very computers that they're bitching about it all on.
This might exist in nature and be responsible for creating terrestrial gamma rays. (TGFs).
In the case of a large thunderstorm the electric discharge that generates the TGF actually starts milliseconds before the return stroke.
Using light would make sense, in fact one approach that is used to generate X-rays is laser irradiation of a low work function metal such as silver or zinc in a vacuum.
Google "Cool-X" as this functions in a broadly similar way using LiTa2O3 or similar and cools + heats this with a Peltier to generate a radiation spike at the temperature extremes.
My physics knowledge ends with rolling a ball down an inclined plane. Could someone explain what they mean by "matter"? When I think of matter I think of hammers and nails and cars. What can be done with the end product of this research? How can something that only exists as photons be called matter or is that one of those physics things? Thanks
OK, to simplify it by a lot. There is no such thing as matter, it's all energy vibrating in the form of strings.
Those strings that sit around, combined with other strings can create that stuff we normally refer to as matter.
Now, take a gamma ray photon, let it slam into an electron, it'll release an electron and positron in opposite directions. Combine those (or any positrons and electrons), you'll get a gamma photon flying out in opposite directions.
Now, to get really strange. Loads of energy in a confined area won't permit that matter stuff to form, too hot and energetic for that rest thing (OK, trainloads of math there). Expand things and let things cool off, matter can form. There is charge-particle symmetry. For all matter particles, there should have been equal antimatter particles. Something double plus ungood if one is trying to make stars and planets. But, there isn't. So, symmetry is broken and some ideas are about that suggest why and how that is.
Proving which one idea is right (or every one of them wrong) is why high energy experiments are performed.
With more knowledge about how the universe works, the more cool things can be invented. Tunneling diodes immediately come to mind, which makes microwave communications cheap and easy. Like with cell phones.
There is also anti-matter, which is exactly* like matter but opposite*, and the anti-matter version of an electron is a positron.
If a positron touches* an electron, both are destroyed* in a burst of photons.
The proposed experiment is to do the opposite - take a burst of photons* and turn it into a positron and an electron.
The smallest stable* type of matter is an electron, so should be easiest to make. Bigger types of matter will be much harder to make.
As to "is that one of those physics things?" - Everything is physics. Dropping a hammer on your foot is physics in action.
* This is a lie-to-children. It's more complicated than that.
No, no the Register has proper journalists who are careful to only Boffinry to describe actual science.
The Dail Mail, Fox News etc tend to report on trick-cyclists as if they were actual boffins.
Don't confuse it with boffo though, that's neither boffinry nor trick-cycling.
I have to agree with a couple of other posters. This story is a complete non-entity. A theory was produced many years ago and a bunch of theoretical physicists have theorised that they can produce an experiment to validate the theory. End of story.
If Prof Higgs said "I've discovered the higgs particle by building a theoretical collider in 20 years time" he'd have been laughed out of the funding committee ... and rightly so.
"We may be able to demonstrate a theory by building this piece of hardware to conduct an experiment", fine, that's what thousands of 'boffins' are doing every day without getting publicity for it!
Not sure why I got the thumbs down, terrestrial gamma ray flashes at 511 kiloelectronvolts are certainly unexplainable without using pair production as the source.
In fact, it appears that if you put enough energy in one place at the same time in any form, be it light, electrons, etc it will result in this effect due to the laws of physics.
Hawking radiation IIRC is one form of this, space is warped so strongly near the event horizon that pairs form spontaneously out of the vacuum and half is emitted.
Here endeth the lesson.
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