New form of matter may lie just beyond the periodic table | Hacker News Reader

New form of matter may lie just beyond the periodic table

phys.org

109 pointsvaliant-comma46 comments

"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).

Neutrons 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.

You'd just just a neutron reflector to shape an omnidirectional source, right?

Do you see any modification to it being feasible?

When particles come together and form a nucleus, it releases energy. This energy is because the new form is more energetically favorable, that is it requires less energy than the particles had separately. This is what makes it stable - it requires input of energy to undo the release of energy. (It doesn't guarantee that some other state is even more stable, like some kind of fission. But going directly back to the form it was in takes extra energy.) This is called the binding energy and it's the same as any other kind of fusion.

I'm up to speed on the physics behind fusion and fission, what I am missing is this fractional fusion/fission idea with respect to quarks.

The suggestion was (as I understand it) that one could "inject/collide/drop" a neutron onto this matter and the neutron would then fission into it's component quarks, capturing them and releasing the binding energy. So this stable matter is a quark soup held together by the strong force because you've managed to get enough up and down quarks together at a low enough energy?

It isn't a mechanism I'm familiar with and I was interested if there was any experimental results to suggest this stuff would behave the way they hope it would.

I think they don't have any experiment results, only some new (unproven) theoretical ideas.

Moreover, I'm skeptical because a similar idea may apply in neutron starts, but the current model of neutron starts has a crust of about 100m (300ft) that has different kinds of intermediate structures with a lot of neutrons and protons and is called "nuclear pasta" https://en.wikipedia.org/wiki/Nuclear_pasta

I can't find how much experimental support has nuclear pasta, but IIUC there are some measurements of the density of the layers of the neutron stars https://en.wikipedia.org/wiki/Neutron_star#Density_and_press...

Exactly. 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.

Uranium isotopes. One of Feynmans safety changes involved changing how uranium was transported (?) in water at the time. Slow neutrons were building up toward criticality in the water. Something like that. I think it’s a standard trick in particle physics to create a particle source by having a radioisotope at the end of a cylinder/magnetic field. Not sure how they’d do it for neutrons but that’s what I think is done.

I would assume it's similar to fusion. The energy would come from the binding energy, but in this case the binding energy between the quarks in QCD?

Neutron 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?

While 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.

I 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.

The 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.

[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?

Maybe 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).

No, 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...

So 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?

The 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#/me...

Link to diagram is broken, correct link here: 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.

>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

Just 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).

Ah, thank you for the clarification.

It could be non-stable udQM. Not all udQM is stable.

Very 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...

Yes, 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.

The 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?

We actually might have already stumbled upon it: https://www.centauri-dreams.org/2017/03/28/the-challenges-of...

Because 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...

If 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.

Hard to find something when you are not looking for it, and don't know what it looks like.

Neat. Reminds me of the smartmatter from world of Anathem.

This page, or something it loads, is causing Firefox to use 100% CPU. Cryptocurrency malware, perhaps?

physorg 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.

Well 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.

Do 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.

Sorry for the late reply!

https://www.sciencenews.org

http://www.sciencemag.org

https://www.nature.com

https://www.eurekalert.org

https://physicsworld.com

Citing their use of ad frameworks isn't an argument against malware.

Non-mobile link: https://phys.org/news/2018-06-periodic-table.html

Thanks! Updated.

... quark matter has the potential to be used as a new source of energy

A new kind of weapon? Renewing the nuclear arms race?

No.

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.

The inefficiency is comparable to those who advocate using antimatter as the ultimate fuel, somehow forgetting that it needs to be manufactured somehow at great energetic expense. If one has a Dyson sphere’s worth of energy to power one’s antimatter-production plant for one’s ultrarelitivistic fleet, that’s great; but if you’re thinking of massive conventional fusion reactors as an intermediary might as well just take those (and their large amounts of light fuels) along for the ride and cut out the intermediary product.

What 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 ?

Not 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.

Who needs deadlier stuff than nukes? Let's root for Quark matter drives instead.

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