8 ms·
New form of matter may lie just beyond the periodic table
- zamalek 8y agoI couldn't find anything on the expected half-life of udQM in the paper, just how stable are we talking here? The theoretical "island of stability" is only relatively stable (minutes to days) and useless for practical applications.
- vinceguidry 8y agoThe article did say that udQM could come in via cosmic rays, this would have to be quite stable over the thousands of years it would take such rays to get to us.
- igravious 8y agoSo what is the QM that is found in colliders? “When produced in a collider, quark matter typically decays within a fraction of a second into stable hadronic matter (with bound quarks).” Obviously not udQM, right?
- vinceguidry 8y agoIt could be non-stable udQM. Not all udQM is stable.
- deleted 8y ago[deleted]
- WiseWeasel 8y ago>SQM consists of comparable amounts of up, down, and strange quarks. One of the new results of the latest study is that quark matter without strange quarks, i.e., udQM, has lower bulk energy per baryon than either SQM or hadronic matter, making it energetically favorable. I would guess QM composed of strange quarks in addition to up and down, and/or below the "continent of stability" size of 300 Angstroms[1]. [1] Correction: A, not Angstroms
- time-of-flight 8y agoJust a clarification: A here doesn't mean Angstroms. It means "number of nucleons", as in carbon-12 is an A=12 system. So they're saying A>300 means "a quark system with >900 quarks"; normal protons and neutrons have three quarks a piece. If I misinterpreted your comment and the above was already clear to you, please forgive my mistake (I didn't want anyone to confuse A for angstroms here).
- WiseWeasel 8y agoAh, thank you for the clarification.
- time-of-flight 8y agoThe udQM they're talking about is in a very different regime than the quark matter produced at RHIC (Relativistic Heavy Ion Collider) and other colliders. In those, heavy ions are collided ultrarelativistically (speed just under C) and for a very brief instant, quarks and gluons are liberated from their confinement inside proton and neutrons to become quark-gluon plasma, or QGC. There are up and down quarks just like in normal protons/neutrons, but also other quarks can be created (strange being the most common). At high enough energies and with particular kinematics, you can make all six quark types: see BaBar experiment, LHC, Stanford Linear Accelerator (SLAC) experiments. In the paper, they're talking about udQM being more stable at zero temperature and pressure, basically "competing" with normal elements. The wiki diagram is useful for reference: https://en.wikipedia.org/wiki/Quark%E2%80%93gluon_plasma#/media/File:Phases_of_Nuclear_Matter.JPG https://en.wikipedia.org/wiki/Quark%E2%80%93gluon_plasma#/me...
- a1369209993 8y agoLink to diagram is broken, correct link here: https://en.wikipedia.org/wiki/File:Phases_of_Nuclear_Matter.JPG https://en.wikipedia.org/wiki/File:Phases_of_Nuclear_Matter.... Apparently wikipedia uses some sort of horrible AJAX crap now; please check that your links work before posting them.
- chris_overseas 8y ago[Disclaimer: I'm not a physicist] I thought that due to relativity, if the elements are travelling close to the speed of light then they could still travel for thousands of years even if their their half lives are much shorter. That's because the element only appears to be thousands of years old from our frame of reference; their age is much less when viewed from their own reference frame. Though given the size and mass of these elements that might be a moot point since it's unlikely they could be travelling at near light speed anyway, due to the enormous energy it would require for them to do so?
- FreeFull 8y agoMaybe they meant that cosmic rays colliding with the atmosphere could produce udQM? Cosmic rays are mostly just really energetic protons (just like what you get inside the Large Hadron Collider, but potentially with even more energy) and low mass atomic nuclei (like alpha particles).
- time-of-flight 8y agoNo, they mean that cosmic rays would be udQM (presumably produced somewhere in the universe and accelerated to us somehow). The premise of the paper is that you need a large number of quarks (for 300+ nucleon system, that's 900+ quarks) to start to enter this udQM regime of stability, and as you say cosmic rays typically have A<40, which is only 120 quarks...
- jonsen 8y ago... quark matter has the potential to be used as a new source of energy A new kind of weapon? Renewing the nuclear arms race?
- kowdermeister 8y agoWho needs deadlier stuff than nukes? Let's root for Quark matter drives instead.
- jerf 8y agoNot from the sounds of it. It's pretty hard to beat existing nuclear weapons, honestly, and even if you could, existing nuclear weapons will be much cheaper for a long time. The bulk of them is already delivery mechanism rather than the warhead.
- sametmax 8y agoWhat would be the point ? We can already destroy a medium country with a few nukes. We probably have enough nukes to blow the entire planet. What would a bigger boom accomplish ?
- deleted 8y ago[deleted]
- deleted 8y ago[deleted]
- semi-extrinsic 8y agoNo. For one, the PRL paper linked here is highly speculative, using a phenomenological model and a lot of assumption and extrapolation. It's full of "may" and "if" and "possibility". Furthermore, what they suggest appears like it would only work as an (inefficient) energy storage; it's not a primary energy source, since you'd have to spend lots of energy first to create this very hypothetical quark matter,and then regain some of that energy as you feed the quark matter with slow neutrons. Finally, assuming everything above actually works, this would be a slow energy release, not fast like in a nuke.
- Sniffnoy 8y agoNon-mobile link: https://phys.org/news/2018-06-periodic-table.html https://phys.org/news/2018-06-periodic-table.html
- sctb 8y agoThanks! Updated.
- ChuckMcM 8y ago"If quark matter is found (or produced in accelerators), it may be stored and then fed with slow neutrons or heavy ions. The absorption of these particles means a lower total mass and thus a release of energy, mostly in the form of gamma radiation. Unlike nuclear fusion, this is a process that should be easy to initiate and control." -- Bob Holdom Oh really? Does the paper give any idea about how that might be accomplished and where the energy would come from? EDIT: Ok, I read the paper (it is pretty short) and now I'm tracking down this reference: [34] G. L. Shaw, M. Shin, R. H. Dalitz, and M. Desai, Growing drops of strange matter, Nature (London) 337, 436 (1989).
- time-of-flight 8y agoNeutrons are a pain to control as a beam because they have no charge, so methods employing electric or magnetic optics are not applicable. Typical pocket sources use the alpha(9Be,12C)n reaction to produce neutrons; if you have a reactor handy, you can moderate (slow) the neutrons produced and use them... this would be by far the most economical option. As a nuclear chemistry PhD, I am highly skeptical of the practicality of this as an energy source.
- semi-extrinsic 8y agoExactly. At best, an inefficient energy storage technology. Edit: the difference from fusion (which is a primary energy source) is that in fusion your starting reactants are available. In this case, you'd have to spend lots of energy in a heavy ion collide to create the initial reactants from scratch. Also, this type of matter is experimentally disfavored in the same way as strange matter: if quark matter was stable, all neutron stars should have converted to quark matter already, but measurements appear to be consistent with them being made from ordinary matter.
- Sniffnoy 8y agoVery interesting. Would it be correct to say that if true this could lead to an earlier end of the periodic table[0] than had been previously predicted? [0] https://en.wikipedia.org/wiki/Extended_periodic_table#End_of_the_periodic_table https://en.wikipedia.org/wiki/Extended_periodic_table#End_of...
- time-of-flight 8y agoYes, one could phrase it that way... but keep in mind that all these theoretical models suggesting an "end to the table" make huge assumptions that are not well-grounded in experimental results. We don't even know where the neutron dripline is for light systems (Z=12), much less the high end of the table (Z=100+). The periodic table is only a useful model (and it is very useful) for nuclear systems acting as a zero-temperature Fermi gas (e.g., nuclei here on Earth). At extremes of temperature and pressure (neutron star merger, say), the idea of a discrete periodic table loses meaning.
- Semirhage 8y agoWhile possible, this seems like an even more tenuous argument than usual for theoretical work on phys.org. The original paper is an ocean of maybe’s and if’s, all couched in unsupported models that may well have no bearing on reality. I’m also a little turned off by the term “continent of stability” which sounds like a grandiose rephrasing of the more commonly hypothesized “island of stability” further down the table. That island is very much hypothetical, and the stability referenced is in comparison to other super heavy elements, not matter in general.
- inetknght 8y agoThis page, or something it loads, is causing Firefox to use 100% CPU. Cryptocurrency malware, perhaps?
- drak0n1c 8y agophysorg has been a very popular site ever since 2004 and well respected for its compilation of scientific and technical papers. It's probably not malware - a more reasonable and common explanation for bad CPU performance is that one of the web or ad frameworks they use is poorly made.
- GW150914 8y agoWell respected? It takes in science (sometimes) and futurist hype (mostly) and belches out something resembling pop science. There are quite a few decent sites that turn papers and headlines into brief articles, but Physorg is not one of them. They are to science what clickbait is to news.
- gmueckl 8y agoDo you have references to sites that are good in your opinion? I am looking for better ways to keep track of progress outside my area of expertise.
- GW150914 8y agoSorry for the late reply! https://www.sciencenews.org https://www.sciencenews.org http://www.sciencemag.org http://www.sciencemag.org https://www.nature.com https://www.nature.com https://www.eurekalert.org https://www.eurekalert.org https://physicsworld.com https://physicsworld.com
- pavel_lishin 8y agoCiting their use of ad frameworks isn't an argument against malware.
- rwallace 8y agoNeutron stars would presumably consist in large part of QM, if it exists. Colliding neutron stars spray large chunks of material therefrom, into interstellar space. It is said that this contributes a significant percentage of the gold and uranium on Earth. If QM were stable, would we not therefore expect to observe it in nature, with abundance at least on the order of gold and uranium? Perhaps there is some factor that depresses its abundance somewhat, but to have gone entirely unobserved, it would have to be many orders of magnitude less abundant than gold. Is there any theory that reconciles stable QM with the observed upper bound on abundance?
- princekolt 8y agoThe comments on the article poked at this question but the answers given there were not very clear for me, so I'll ask here: If this udQM is so stable, why didn't we find any of it in nature so far? We certainly would know we don't understand this matter if we stumbled upon it... right?
- teilo 8y agoBecause it would be in such small and diffuse quantities that unless we were specifically looking for it, we likely wouldn't find it. As for stumbling upon it, all our measurement techniques are calibrated to hadronic matter, so...
- Isinlor 8y agoWe actually might have already stumbled upon it: https://www.centauri-dreams.org/2017/03/28/the-challenges-of-przybylskis-star/ https://www.centauri-dreams.org/2017/03/28/the-challenges-of...
- KayAar 8y agoIf this udQM with A above 300 were stable it would have been produced in neutron star collissions, along with other heavy elements such as Au, and there should be traces of it in the earth. So far no such udQM has been found.
- teilo 8y agoHard to find something when you are not looking for it, and don't know what it looks like.
- pavel_lishin 8y agoNeat. Reminds me of the smartmatter from world of Anathem.