17 ms·
Scientists create matter from pure light, proving the Breit-Wheeler effect
- was_a_dev 5y agoPublication link: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.052302 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12...
- adrian_b 5y agoFree link: https://arxiv.org/abs/1910.12400 https://arxiv.org/abs/1910.12400
- eloeffler 5y agoThis induces some severe Star Trek replicator fantasies. Though I assume the result of this compares to having a cup of earl like opening a lego drawer vs. a visit to Legoland
- TeMPOraL 5y agoI've been thinking about it a lot, and I feel that the road to Star Trek replicator is not through matter synthesis. Instead, a better way - perhaps the only way - is through some sort of universal feedstock (or few of those) and a library of carefully designed chemical processes (possibly involving nanoengineering). It seems nice at first - the idea of turning raw energy into things. But the amount of energy required is just ludicrous, going through antimatter intermediary is extremely dangerous, and... there's really no point. It isn't buying you anything. If you tried to store the amount of energy needed to replicate a kilogram of stuff in some advanced batteries, you'd quickly discover that those batteries now weigh a kilogram more. E=mc^2 works both ways - storing energy adds mass. So, unless you can literally fly through a star and suck it dry as you replicate your tea, replicators won't be reducing weight of a starship. It turns out, matter itself is the ultimate energy storage device. And then, turning energy into matter just gives you elementary particles. You need more work to assemble that into useful stuff. This is nuclear work, and then chemical work. So why not just ditch the matter/antimatter intermediary, and start from some feedstock that already has the necessary elements, and is optimized to be easy to react into the stuff you want (and then to be recycled from that stuff)?
- imglorp 5y agoI think this is right. And this, plus unlimited power (coming soon) gives you the route to the Roddenberry economy where everyone works to improve themselves and society and there is no money. Think about it. If you put dirt in the replicator and you get a Rolex or a hamburger or a garment, you don't need money for anything: everyone is equal and they can go off and study or work on whatever they want. Wealth is a false proxy for social status anyway.
- lippel82 5y agoReal Estate! That'll be the only valuable thing in such an economy.
- White_Wolf 5y agowe'll all have a pocket universe to design as we wish :D
- monkeybutton 5y agoThat's something that always bugged me. Why does Picard get to have an entire, private vineyard to himself?
- layer8 5y agoMaybe when beaming down to earth they really beam down into a holodeck (or the Matrix).
- CalRobert 5y agoPrimogeniture, apparently. Great thread athttps://mobile.twitter.com/sarahtaber_bww/status/1200230627544649735 https://mobile.twitter.com/sarahtaber_bww/status/12002306275...
- TeMPOraL 5y agoThat's a great (and long) thread. Reminds me of a pet theory I have: that the post-scarcity utopia of the Federation is based on expansionism, and not sustainable. They've managed to turn Earth into a paradise and give (mostly) everyone great life quality, but they did this by doubling down on exponential growth, which manifests in the constant need to get more and more planets to join the Federation. You can see the expansionist vibes all over the show, and they've even been hinted at by various aliens in DS9 (although without any mention of economic implications).
- api 5y agoUnfortunately the energy requirements of those replicators would be ludicrous… like 10x the yield of the Tsar Bomba (largest H-bomb in history) to make a cup of tea. Replicator malfunction would be an extinction level event. Just do E=mc^2 on the mass of your cup of tea.
- Retric 5y agoMore like 1/10th the Tsar Bomba. 1KG = 9e16J, where the bomba was ~209 PJ or 2e17J and a cup of tea is only like 0.2kg so 2e16J.
- vanderZwan 5y agoSo only merely wiping a city off the map, nothing as dramatic as an extinction level event, then? ;)
- rainworld 5y agoTwice that. One cup antimatter, one cup ambient matter.
- ta988 5y agoI would prefer a cup of dark matter please.
- airstrike 5y agoJoseph Mallozzi has you covered, then
- Retric 5y agoNot everything that produces mater also produces antimatter otherwise the universe would be a 50:50 mix of each. Why Baryon asymmetry exists is unknown, but as long as we’re talking magic tech we might as well make it efficient.
- 5y ago
- simion314 5y agoStar Trek will use existing matter to replicate stuff(but maybe not all the time) , otherwise it would cost a lot of energy.
- newpavlov 5y agoYou forget about one smaaaal issue: disposal of created antimatter. Also why bother creating matter from energy when even today we are able to create stockpiles of raw elements (although quite inefficiently and with almost no control over isotopic composition). Assuming that waste will be converted back to those elements, you don't need those stockpiles be too big and energy consumption will be modest when compared to creation of matter directly from energy.
- csunbird 5y agoWhat about using the antimatter as engine fuel?
- Khoth 5y agoMuch like how we can turn lead into gold but don't, this process isn't remotely cost-effective. There's plenty matter lying around that you can have for probably 20 orders of magnitude cheaper.
- noobermin 5y agoI was surprised because I thought the Breit-Wheeler Effect has been demonstrated already. It just looks like what they mean here is single photon (or really, two photon), not the so-called strong field Breit-Wheeler that was demonstrated at SLAC and with powerful lasers for decades now.
- jdbburg 5y agoOne of the authors here. You are correct, the famous SLAC result already demonstrated that light can be converted into matter, but they needed several photons >4, average of about 6 - that is the so called non-linear Breit-Wheeler (BW) process. This result is the original linear BW process where only 2 photons collide. The main difference is that for the linear BW you need much higher energy photons. Also, in this experiment we are able to measure the wavefunction of the two-photon system, which proves other aspects of the original predictions by Breit & Wheeler and others.
- suifbwish 5y agoI was always curious before I heard of this today what would happen if you concentrated more and more light into a ultra fine point. It makes sense that at some point particles would begin to emerge as photons appear to have various electromagnetic properties and also carry a small amount of kinetic force (solar sail principle)
- Tepix 5y agoFascinating. Could two cooperating civilizations a and b use this effect to create matter (perhaps even something self-replicating?) at a 3rd location in space? incoming ascii art (a)---(c) | | | (b)
- adrian_b 5y agoIt is very unlikely that teleportation could ever be achieved by generating matter from light. There are 2 problems. First is that the energy required for generating a human-sized body is huge, several hundreds times greater than that of a nuclear bomb with the same amount of active material. Second is that even if you would be able to do that, you would make 2 bodies, one of matter and the other of antimatter and you would not be able to dispose of the antimatter one except by causing an explosion equivalent with hundreds or thousands of nuclear bombs. In general, for now it appears to be completely impossible to do teleportation towards an arbitrary place. At most, it could be imagined a method that would work between 2 large installations existing at the end points, where the destination could manufacture a replica of what was sent from local materials (e.g. by placing one atom after another until an exact replica is made; extremely unlikely, but not completely impossible).
- jamiek88 5y agoWouldn’t the no cloning theorem make an exact replica impossible?
- adrian_b 5y agoThe "no cloning theorem" refers to replicating the same quantum state. It does not apply to making a replica of a body that is composed by the same kinds of atoms linked in the same way between themselves, which can be considered as identical with the original for any practical purposes. In a very rudimentary form, such technology exists today, it is possible to remove one atom at a time from a certain position of a body and identify it with a mass spectrometer and it is possible to grow a structure a few atoms at a time. It is likely that the precision of such techniques could be improved well enough to be able to replicate some extremely small microscopic objects. The most difficult limitation to overcome is the speed of the process. To be able to make some human-sized object atom-by-atom and molecule-by-molecule in a reasonable time would require a many orders-of-magnitude higher speed than possible with the current technologies.
- NiceWayToDoIT 5y agoSo, after all, it seems science fiction writers are prophets in disguise. List of Star Trek inventions that came true: https://qz.com/766831/star-trek-real-life-technology/ https://qz.com/766831/star-trek-real-life-technology/ Although, from "light into electron and positron" to "Tea, Earl Grey, Hot" there is a long way to go.
- whatshisface 5y agoYou can't give credit to Star Trek because I am pretty sure this possibility was understood before Gene got to it. ;)
- NiceWayToDoIT 5y agoTrue, Star Trek initial release was October 14, 1986 while theory was there from 1934. Thanks for correction.
- dekken_ 5y agoExcept electrons aren't matter.
- ironSkillet 5y agoI am positive that electrons are matter. Never heard your claim before.
- dekken_ 5y agoYou are positive you were told that electrons are matter maybe. This is the standard (see: current) model, in QFT electrons are not particles, so are not leptons, so are not matter.
- petrocrat 5y agoIs the mass measurement of electrons an abberation then in the QFT interpretation of the empirical data? Or is it that energy can have mass prior to being converted under some conditions?
- dekken_ 5y ago> Is the mass measurement of electrons an abberation then in the QFT interpretation of the empirical data. I'm not sure this is resolved. see: https://en.wikipedia.org/wiki/Quantum_electrodynamics#Conclusions https://en.wikipedia.org/wiki/Quantum_electrodynamics#Conclu... > Or is it that energy can have mass prior to being converted under some conditions? Using https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalenc... you can (theoretically) convert between energy and mass, and then measure everything as https://en.wikipedia.org/wiki/Electronvolt https://en.wikipedia.org/wiki/Electronvolt. I have yet to see anything create protons from energy, so I am hesitant to do this.
- TeMPOraL 5y ago> I have yet to see anything create protons from energy, so I am hesitant to do this. Won't a proton/antiproton annihilation also create two photons? If so, wouldn't that also work in reverse?
- neonnoodle 5y agoWe have matter at home.
- lmilcin 5y agoNow the real question is, when can I order my replicator and dilithium crystals to power it?
- jcims 5y agoI have had this mental question about 'what time is it when photons collide'. Given that a photon could have been travelling for a million years colliding with one that has only been travelling for a microsecond, and from the photon perspective there is no passage of time and no distance. I then kept reading things that tell me photons don't interact, which saddened me because I like the question. This now appears to not be the case, is there a specific condition under which photons can interact like this?
- jdbburg 5y agoIn classical electromagnetism photons (light) do not interact, period. But in quantum mechanics the photons can briefly fluctuate into electron + positron pairs which allow them to interact with each other. But the probability for interacting is very small AND you need enough energy to make the electron positron pair (for the Breit-Wheeler process), so it is very rare in practice. I am not sure about the "time" the photons collide, but the interesting thing is that the Breit-Wheeler process is what determines the opacity of the universe - since high energy photons traveling through the universe can hit low energy photons from the cosmic microwave background and convert (disappearing) into an electron positron pair.
- jerf 5y agoThis is a good example of one of the errors that I often see in what is otherwise the best scientific writing, which is either forgetting to specify what a certain model says, or simply straight up forgetting/confusing that a certain model isn't reality. Maxwell's equations say that light doesn't interact. Maxwell's equations are known to be wrong in that way. They're still a very good simplifying case that you can do very well with using, by all means, just like Newtonian physics in the right conditions, but they aren't the way reality works. Maxwell's equations also have no place to put a gravity term, yet gravity clearly affects light. The one I probably see the most often is articles about black holes confidently speaking about "what goes on below the event horizon" from an Einstein relativity point of view, which is where you get all the singularities and ring singularities that lead to different universes somehow, etc, again either forgetting to point out or simply forgetting entirely that those are the specific predictions of Einstein relativity, which is known to be inadequate to describe the inside of a black hole. It is certainly fair to discuss that theory's predictions, and whatever really is happening in there, relativity will certain shine some sort of light on it, but it is a mistake to present it simply as "what happens on the inside". The model is known to be broken here. I am working out how to phrase this in a way that makes sense to the HN crowd because this tends to ruffle feathers when I say it, but this is all what should be well-known stuff. It's not like I'm "denying science" when I say this; quite the contrary! It's "denying science" when you insist the known-by-science-to-be-broken models are in fact not broken where the science is pretty clear that they are.
- TedDoesntTalk 5y ago> they collided gold nuclei accelerated to 99.99 percent of the speed of light. How did they achieve that?
- detaro 5y agoSentence before: > Relativistic Heavy Ion Collider https://en.wikipedia.org/wiki/Relativistic_Heavy_Ion_Collider https://en.wikipedia.org/wiki/Relativistic_Heavy_Ion_Collide...
- turdnagel 5y agoAt the risk of sounding like an idiot, why doesn't this happen when you point two flashlights at each other? Or point a flashlight at the sun? Or when light from one star reaches another? Etc etc.
- platz 5y agodoes your flashlight emit gamma rays
- choeger 5y agoIt's funny that you ask, but I have this flashlight that I found in my weird neighbor's garage/machine shop...
- stronglikedan 5y agoIs your weird neighbor's surname, Smith, by any chance?
- turdnagel 5y agoI also mentioned stars, but thanks.
- Y_Y 5y agoYou need to have enough energy (aka. mass, physicist will use the two interchangably) to pay for whatever particle you want. An electron weighs about 10^-30 kg, or about half a megaelectronvolt, but because of cosmic balance you'll want to make a positron at the same time. So your total bill will be about 1 MeV. Visible light photons have about 1 eV of energy, if you want a photon with an MeV then you're past even hard x-rays and into gamma rays. This process is the same as matter-antimatter annihilation, except backwards. A proper explanation would take several years. By the way, you can use more than one photon at a time, but to my knowledge nobody has managed to fuse the million flashlight photons you'd need to do pair-production.
- deleted 5y ago[deleted]
- smurpy 5y agoIt looks like one of the authors is on HN with us. Can you offer any insight into the cause of the confusing language in the "Science News" piece? It reads like it was written by a bot not a human. In the sentence "With the theory physicists Gregory Breit and John Wheeler were able to prove that when two high-energy photons collide, a positron and an electron arise, i.e. matter is formed" shouldn't the word be "predict" not "prove"? A more flagrant example of a strange word choice for a human science writer to make is "A direct conversion would require a laser that emits gamma-ray photons in a highly concentrated steel." Shouldn't the word "steel" instead be "beam"? This seems like the sort of thing an uncomprehending bot might do, conflate those two words. Are my the nits I've picked, above, unfounded? Does the author of the original paper have any information which might suggest that an actual human wrote the "Science News" piece? If not I would suggest that we've got a bot on the loose! Eeek! Further, I think I'm seeing rather a lot of "content" floating around recently which smacks of machine origins. Also, to Daniel... Great paper. Amazing stuff!
- jdbburg 5y agoAuthor here, thanks! I am not familiar with this website (science-news.co) so I cannot comment on the quality of the writing (or human origin). I agree with you that "prove" should be "predict" - they did not prove anything except that from a theory standpoint, this process can happen in quantum mechanics. The sentence about lasers is also strange, I have no idea what is meant there. My only guess is that it might be trying to describe some laser experiment that uses lasers to "heat" a hohlraum to produce a field of photons. Then some other high energy photon beam is used to collide with the photons inside the hohlraum. edit: Original article from DOE press release is here with a bit more info: https://www.bnl.gov/newsroom/news.php?a=119023 https://www.bnl.gov/newsroom/news.php?a=119023
- dang 5y agoOk, we've changed the URL to that from https://science-news.co/scientists-create-matter-from-pure-light-proving-the-breit-wheeler-effect/ https://science-news.co/scientists-create-matter-from-pure-l.... Thanks!
- tablespoon 5y ago> A direct conversion would require a laser that emits gamma-ray photons in a highly concentrated steel. However, research has not yet been able to develop such a laser. What does "highly concentrated steel" mean here? All my Googling is getting hits for the metal, but I feel like something else is meant here.
- r721 5y agoThis domain was never submitted to HN before, so I suspect this is some other article which was put through the so-called "synonymizer" software. Here is an article from Brookhaven Lab website: https://www.bnl.gov/newsroom/news.php?a=119023 https://www.bnl.gov/newsroom/news.php?a=119023
- tablespoon 5y ago> This domain was never submitted to HN before, so I suspect this is some other article which was put through the so-called "synonymizer" software. If that's true the domain should be banned. There's no point in reading things that garbled plagiarizations.
- r721 5y agoBetter article: https://www.bnl.gov/newsroom/news.php?a=119023 https://www.bnl.gov/newsroom/news.php?a=119023
- pretadank 5y agoCurious if the reverse is true ... also is momentum conserved in this, then wouldn't the positron electron pair be shooting off at the speed of light, and if not where is the extra energy going? Or have I missed something?
- pretadank 5y agoCurious, can this process be reversed? Also, is momentum conserved, then if it is wouldn't the positron and electron be ejecting at the speed of light (and wouldn't that violate the principle that matter cannot reach the speed of light)? If not what is slowing them down / where is the energy going? Could this be theoretically a way to power something? Either by the ricochet of the particles off something, or by using them to energize something?
- whatshisface 5y agoAll quantum-mechanical processes can be reversed. In fact, this process is actually a lot more common in the other direction; a positron and an electron making a pair of photons is matter-antimatter annihilation and it happens all the time. This is because a couple photons are thermodynamically preferred over an electron-positron pair at room temperature. It's kind of like how allotropes of solids will form and reform as you change the heat and pressure.
- tsimionescu 5y agoMomentum is mass times velocity. Momentum is conserved, but you're going from (probably) mass-less photons moving at c to mass-ive electrons/positrons moving at <c.
- drdeca 5y agowhen you say mass times velocity, I take it you mean relativistic mass? I assume you know all the following, and I'm just saying it to explain my reasoning for the above / to elaborate for other readers. One can certainly pick a frame of reference such that the total momentum of the electron and positron afterwards is non-zero, and therefore the total momentum of the photons beforehand (in that reference frame) will also be non-zero , despite photons having (or, believed to have, but I believe it also) 0 rest mass.
- ivoras 5y agoCan someone ELI5 the relationship between electrons and photons? So far we have: * Electrons emit photons when going from a high energy state to a low energy state (but remain electrons) * Two photons colliding produce an electron-positron pair (always exactly one?)
- tsimionescu 5y agoThere's no ELI5 answer. You can look at some Standard Model charts. In principle, any particles in the SM can interact or decompose into any other particle, as long as mass-energy, spin, charge, color charge etc are conserved. The probability of many of these interactions may be minuscule.
- jacinabox 5y agoMatter from pure light huh, today's job market is getting competitive for sure.
- Chris2048 5y agoSo, a question: traditional objections to galactic travel (e.g. 1G accel) is the requirement for huge amounts of propulsion mass. Even with a method of perfect E=mc^2 of some special fuel matter, you still need a whole load of propulsion mass to chuck in the opposite direction, which in turn requires more energy to accelerate. the question is, could we get around that by converting from mass-less forms of energy, and generating mass on-the-fly, skipping the need to accelerate tons of acceleration mass; or is there some restriction that would disallow this? If I fire 2 photons at each other on a ship travelling at 0.5c, and this creates 2 particles e+ and e-; would the particles also be travelling at 0.5c along with the ship; would their velocity/momentum be in random directions etc?
- pacija 5y agoMatter (aether) is constant, it cannot be created or destroyed. Mass is created in places where matter's (aether's) density gets slightly higher or lower than its baseline density. Photons don't exist. You're welcome.
- SeanFerree 5y agoVery cool!!
- chana_masala 5y agoAs a Saivite, this perfectly aligns with both my religious and scientific understanding of the universe.