Has anyone ever aimed a Gagillion lasers (or whatever) at a point and had a bit of matter appear?
It’s really hard to do, but I think this paper discusses some experimental proof that it is possible. This is terrawatt laser pulses interacting with electrons, but matter that wasn’t there is being produced. (it’s measurable because some of the matter is positrons and those give a distinct signal when they annihilate themselves)
To do it without having matter to start from, other papers talk about possibly being able to “boil vacuum”, where it is theorized that ‘virtual particles’ will take the same role the electrons take in this experiment. So it has to be coherent, phase aligned light beams, because it’s the electric field components that matter. So you need some really good lasers that are in phase with each other where their beams cross. And apparently if you set it up just right, matter will begin to appear, and then you have to somehow prevent it from annihilating itself.
Does anyone know what kind of matter that is? For instance, is it one of the elements?
Going the other way is essentially what happens when you crash small particles going really fast into things/each other. Get a proton up to 99+% lightspeed and crash it into another going the other way, and particles with masses a lot more than 2p show up. Admittedly your starting with small masses instead of just light, but that’s because it’s a lot easier to get them to interact, not because you’re not doing the same thing, converting kinetic energy to mass.
Positrons are sub-atomic, so, smaller and more fundamental than chemical elements.
I’ve read it will be positron/electron pairs. With even brighter lasers (about 2000 times brighter), it will be proton/anti-proton pairs.
At that point you have no elements. What you have to do now is trap the anti-protons and positrons together, without ever touching them with ordinary matter (like the walls of your setup), cool them (apparently you can cool with lasers or magnets, I don’t understand how tbh), and they will form anti-hydrogen gas.
Oh, you can make hydrogen the same way, though what’s the point.
If you want elements you’d now have to compress the anti-hydrogen gas to extreme temperatures and pressures (done with magnets or lasers or electric fields, since you can’t touch it) and force it to fuse. You could eventually reach any element you wanted that way.
It happens on the subatomic level in pair production.
The positron is the antiparticle to the electron. It’s a small fundamental particle with a charge of +1, compared to the electron, a small fundamental particle with a charge of -1.
If you had a large amount of energy in a region of space, you’d expect some measurable of electron-positron pairs to be produced, which is usually diagrammed as two photons coming together to produce an electron going one way and a positron going the other. The reason is simple: Charge is conserved, so if you have zero net charge going into an interaction, you must have zero net charge coming out. A photon has zero charge, so two photons still have zero charge, so if they forms a charged particle, it must form matched sets, such that the sum of all charges it produces add up to zero.
Why two photons? Again, fairly straightforwards, and it illustrates another conservation law, this time the conservation of momentum. Essentially, we observe the positron and the electron speeding away from each other, so they have opposite momentum, one with momentum +p (that is, it’s speeding off in the positive x direction with momentum p), one with momentum -p, let’s say. Well, momentum is conserved both in amount and direction, so to get that you need the same momentum coming in as going out. Photons, even though they’re massless, do carry momentum, so you need a photon with momentum in the positive x direction and one with momentum in the negative x direction.
That massless photons have momentum is probably one of the earliest shocks to people who have a naive intuition about subatomic particles as little ball bearings flying around and bouncing off each other. It’s straightforward to model it if you drop the pre-relativistic notion of momentum as mass times velocity and think about the energy-momentum four-vector, which basically says that rest energy and three-dimensional momentum are aspects of the same quantity, called four-momentum, and how much rest energy versus three-dimensional momentum you observe an object having depends on your speed relative to that object. Since photons have no rest mass, and therefore no rest energy, all the energy they do have is in the momentum portion of the four-vector, so they do have momentum. This is what we observe.
And that is where E = mc[sup]2[/sup] comes from, as this page demonstrates.
Going “the other way” is what high-energy photons do all the time. When a gamma ray* ends its journey, it almost always does so by converting into an electron and a positron in the presence of an atomic nucleus. (It has to be near something like a nucleus so that it can share some energy and momentum with it, else conservation laws couldn’t be satisfied.)
As has been noted, you don’t need photons to do this do, since smashing any particles together at high speed is exactly what you’re after (i.e., creating massive particles from energy). This is at the heart of experimental particle physics research.
[sub]*above 5 MeV or so[/sub]
The “gagillion lasers” approach has been used to make stuff really hot, but it isn’t viable for particle production in the way you are thinking. Each photon in a laser beam has too little energy to be useful for this, by a factor of a million. The laser is high power because there are a lot of photons, but those photons aren’t talking to each other on the subatomic scale, so you can’t benefit from that total energy except macroscopically.
Going to higher energies (though not with lasers as noted above) can get you many possible products, not just proton/antiproton pairs. Those are pretty far down the list of things possibly produced, actually.
My inner 12-year-old really wants to go there and burn up random things. Maybe see what happens to a jar of pickles when hit with the world’s biggest laser.
Reason #217 why I’m not a scientist.
Of course, this kind of thing is happening constantly, wherever the Sun is shining on plants. The equivalent of a gagillion lasers is beaming photons onto a leaf, which converts the photon plus CO2 plus H2O into sugar and O2, with the sugar and O2 having more mass than the CO2 and H2O at the beginning. The reaction is just moving electrons around, not creating new ones, but the result is indeed more mass than at the beginning.
Heck, for that matter, there’s a temporary creation of mass inside every fluorescent light or glow in the dark sticker.
This aspect of mass/energy equivalence isn’t the sort of thing the OP is after, though. None of this causes “a bit of matter [to] appear”, as sought in the OP.
One nitpick: To make protons and antiprotons instead of electrons and positrons, you don’t need to make the lasers a couple thousand times brighter; you need to make them a couple thousand times bluer. Making the lasers brighter will mean that you’ll get more of whatever particles you’re getting, but it won’t let you create new kinds of particles beyond what you’re already getting.