Scientists Propose Collider That Could Turn Light Into Matter

An anonymous reader writes "Imperial College London physicists have discovered how to create matter from light — a feat thought impossible when the idea was first theorized 80 years ago. From the article: 'A pair of researchers predicted a method for turning light into matter 80 years ago, and now a new team of scientists are proposing a technique that could make that method happen in the purest way yet. The proposed method involves colliding two photons — the massless particles of light — that have extremely high energies to transform them into two particles with mass, and researchers in the past have been able to prove that it works. But in replicating that old method, known as Breit–Wheeler pair production, they had to introduce particles that did have mass into the process. Imperial College London researchers, however, say that it's now possible to create a collider that only includes photons.'"

Comments

Re:What am I missing here?

[Anonymous Coward]

Being bosons just means you can pack multiple quanta into the same state.

All particles interact (otherwise, how would we even know they "exist"?), and photons interact electromagnetically. That means that they can induce the vacuum to produce pairs of electrically charged particles: say, an electron and a positron. Usually, those particles are just quantum fluctuations or "virtual particles", living for a tiny fraction of a second due to Heisenberg uncertainty. However, if two photons have enough energy between them (at least equal to the mass-energy of the pair), they can give their energy to the electron and positron and turn them into real particles. That's what they want to do here: get two photons to give their energy to a virtual particle pair, making it real.

Re:how soon before

[davester666]

I believe the summary is confusing concepts. A 'proposal' for how to do something, but not actually having implemented the proposal to see if it actually works IS NOT the same as 'discovering how to do something'.

There is a huge, fundamental gap between

I suggest we try doing X to accomplish Y
and
I did X and accomplished Y

Re:This was already done back in 2001

[Karma Bandit]

What? How can you link a paper like that and completely not understand its contents? No, they did not create matter out of light. The important thing from that paper is that the light was frozen in place while it was traveling through the material. It's a nice experiment, but has absolutely nothing whatsoever to do with photon-photon interactions and creating of particle-antiparticle pairs. The word "mass" doesn't even appear in the paper, for example. The photon energies are eV level in that paper, and photon-photon interactions require billions times more. Like, gamma rays, not visible light.

You might argue, pedantically, that while the light was trapped in the sodium in that paper, the kinetic energy of the sodium atoms increased. And due to relativity, increase the kinetic energy of something also increases its mass. Well, you would be right, and that happens every time the sun shines on something and warms it up. But when you talk about creating matter from photons, they mean making brand new particles-- that is, making even the *rest mass* portion of their energy out of the photons-- not just speeding up existing particles. And that just cannot be done with light near the visible spectrum.

Re:Do it, then report it.

[Farmer Tim]

Saying that they're publishing in an attempt to secure funding is the least insightful comment you could possibly make, because that’s precisely how expensive “serious science” gets done: you put your theory up for peer review in a publication like Nature Photonics, and if it’s sound then you go into the contest for funding an experiment. Using your logic we should’ve built the Large Hadron Collider before the theoretical merit in building it was confirmed; if you can’t see why that's a phenomenally stupid way to allocate finite resources then sorry, but I have to doubt you're clever enough to prove a conjecture theoretically, let alone practically.

Re:how soon before

[fiziko]

Not at all. In science, there is just as much validity to "we did X but didn't get Y" as there is to "when we did X, Y was accomplished." In fact, Michelson and Morley are a prime example of "we did X but didn't get Y" in 1887, and they won the Nobel prize for it in 1907.