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Alexander Bolonkin has proposed the possibility of manipulating nucleons to produce stable, macroscopic structures of nuclear matter at zero pressure (which he calls "AB-matter"), by analogy with the nanotech ideas of directly manipulating atoms to build high-tech materials.

The basic claim is that an unbounded number of alternating protons and neutrons can be arranged in a fiber held together by residual nuclear force and a small contribution from magnetism due to the nucleon magnetic moments, and prevented from collapsing and held rigid by electrostatic repulsion. Superstrong macroscopic structures can then be built by combining these basic nuclear matter needles.

Bolonkin is a legitimate scientist (PhD in aerospace engineering), but not a nuclear physicist, and has gotten papers on this stuff published, but not in physics journals (for example, "Femtotechnology: Nuclear AB-Matter with Fantastic Properties" in American Journal of Engineering and Applied Sciences and "Femtotechnology: Design of the Strongest AB Matter for Aerospace" in Journal of Aerospace Engineering). Furthermore, nobody else seems to have published anything on this topic, all of which makes me rather skeptical of his claims.

So, ignoring the issue of how you'd construct it in the first place (assume we find some helpful Cheela to do it for us or something), could a linear arrangement of alternating protons and neutrons at zero pressure (i.e., not confined in a neutron star or something) remain stable and not collapse into one big nucleus, or segment itself into a bunch of individual nucleii? And does it make any difference if the fiber is kept under tension by some external means?

Logan R. Kearsley
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  • You are falling for a pseudoscientist. I have a degree in experimental high energy physics, which is much closer to nuclear physics than aerospace engineering ever will be. I would not, in a lifetime, think about using my title to justify that I have the first idea about nuclear physics. To be very honest with you: the man is full of it. – CuriousOne Sep 08 '14 at 06:43
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    Oh, I'm pretty certain he's full of it. It just bothers me that I don't know exactly why. There is this conflict between "that shouldn't work" and "Er... why not? I don't actually know enough physics to say...." – Logan R. Kearsley Sep 08 '14 at 16:46
  • Generally speaking, the scientific method advances based on positive evidence. If there is no evidence in nature for something, it is not a good idea to throw it on the wall to see if it sticks, but that's pretty much how all of pseudo-science works. I have no access to the paper, so I can't tell you where this phantasy falls apart. In the right regime (e.g. in the environment of a neutron star), there may even be something like nuclear chemistry (albeit of a very different form than proposed). But then, so far we can't replicate that state of matter... so there is no evidence. – CuriousOne Sep 08 '14 at 16:56
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    @CuriousOne instead of "this is clearly a pseudoscience guy" it is better to elaborate why this (probably) wouldn't work. Something along the lines that electrostatic force which repels protons remains stronger on long distances than any attractive force involved, so such structure would probably rip itself apart due to the electrostatic repulsion. And for shorter strings of nucleons the stability would probably be questionable. However, notice the mandatory "probably" in each sentence. – Danijel Oct 19 '14 at 20:50
  • @Danijel: I wanted to elaborate on one of the obvious signs of pseudo-science: false titles and titles that do not match the field. I find that a much more useful criterion for layman to identify pseudoscience than to make a technical argument that they can't decide on its merits any more than they can decide the merits of the pseudoscience claim. Not everything in life is solvable with a science argument. Sometimes common sense works just fine. – CuriousOne Oct 20 '14 at 01:29

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Everything that's physically possible occurs naturally. Atoms arrange themselves naturally into one- and two-dimensional structures (lipid and polymer chains in 1D, graphene and nanotubes from soot in 2D) and so we're able to envision techniques to mass-produce those. But there's no evidence that nucleons form chains in nature (at least outside of neutron stars), and so no reason to believe we could construct such a phase.

In fact we can be a little more quantitative. Different nuclei have different shapes; the sign of their quadrupole moment tells you whether they are primarily cigar-shaped ("prolate") or coin-shape ("oblate"), and octupole and higher moments describe more complicated shapes than ellipsoids. There are a small number of nuclei which are super-deformed in their ground states, with their long elliptical axis two or three times the length of their short axes. But those superdeformed nuclei tend to have masses $A\approx 80\mathrm{-}100$, so an ellipsoid with 3:1:1 axis ratio is a pretty long way away from a one-dimensional chain.

You have to remember the reason that the periodic table has finite size: the nuclear force, which holds nucleons together, is a contact force with a potential like $$ V \sim \frac \alpha r e^{-r/r_0}. $$ For the attractive part of the nuclear interaction the range $r_0$ is set by the pion mass to about 1 fm. If you separate two protons by several femtometers, as in a heavy nucleus, the attractive interaction is exponentially weakened relative to the electrical repulsion. I see no reason to expect this to be any different for nucleons in a hypothetical chain.

rob
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Sounds like kook material. If his hypothetical material consists only of N neutrons and Z protons, then it has a nonzero net electric charge and can't possibly be a stable form of matter. The electrical potential energy would go like $Z^2$, while the nuclear potential energy would vary linearly with $N+Z$, because the nuclear force has a short range.

  • One presumes the complex would be neutralized by a surrounding electron cloud, just like nucleii in regular atomic matter are. – Logan R. Kearsley Sep 08 '14 at 04:07
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    @LoganR.Kearsley: I don't think that works, because the scale of the electron cloud would be $\sim 10^5$ times larger than the nuclear scale. That's why electrons don't stabilize real nuclei that are unstable with respect to fission. –  Sep 08 '14 at 21:45
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    You worded this badly: "it has nonzero net electric charge and can't possibly be a stable form of matter" is obviously wrong if you don't care about the electrons, since literally every stable nucleus has a net positive charge. What you meant, I think based on what you said later, is that, after you get ENOUGH charge close enough together, it will inevitably overcome the nuclear force ("proton drip"), and the only way to prevent this is to use so many more neutrons that the protons are reasonably spaced apart, which in normal nuclei anyway creates its own problems. – Mr. Nichan Jun 26 '21 at 07:10
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I am not a nuclear physicist but I have studied these structures. Bolonkin is not a fool. He knows what he is talking about. The claim that "everything possible occurs in nature" is not true. While fullerenes and tetrahedral carbon/diamond does occur, and while you could point to "natural" stainless steels, such as iron-cobalt-nickel meteorites, I can point to unnatural, manmade structures that do not occur in nature. Japanese metallurgists have made an Austenitic Stainless steel called H-1 which uses nitrogen in place of carbon in the iron matrix, and thus it is nearly 100 percent impervious to rust and is used in knife blades by Spyderco knives. Stainless steel does not occur in bone structures and yet steel is ten times stronger than bone. Because something does not occur in nature does not make it impossible.

I guess the two main issues here are stability issues: 1 Could you make subatomic/nuclear femto structures that take forms other than a glob or drop. Well, what if the assumption that the nucleus is a sphere are false? Buckminster Fuller proved the vector equilibrium structure/tensegrity/geodesics are found in nature, from the atom and molecule on up to the galatic level. You are ASSUMING that SUB-Atomic structures are chaotic and cannot have structures like tubes, sheets, bars, rods, and so on and so forth. If we find these structures in the atomic world (fullerenes for example), why wouldn't they exist even at smaller scales, like this: ? https://arxiv.org/abs/hep-ph/0112066

" Motivated by Fullerenes, in this Letter we point out the exis tence of new ge- ometric structures in QCD with high spatial symmetry. We det ermine the geometric structure and the characteristic “magic numbers ” of these configu- rations, using analogies with carbon Fullerene structures . We explore some of the interesting topological structures that can be created by QCD networks and closed cages that may be produced in high energy nuclear r eactions joining multiple QCD junctions and anti-junctions. Although the QC D Lagrangian is CP even, we point out that the junction and anti-junction bui lding blocks can be used construct CP odd configurations that may also serve as domain walls between inequivalent ( θ ) QCD vacua."

At least consider it

Urb
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FemtoMan
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    That particular paper does not seem to provide any particular support for Bolonkin's AB-matter ideas. It describes geometric structures of baryons and anti-baryons which, while representing islands of relative stability among possible quark-gluon structures, are "most likely unstable" against self-annihilation. – Logan R. Kearsley Sep 08 '14 at 19:06
  • You seem to have missed the point of my answer. While it's certainly true that "everything possible occurs in nature" is a slight exaggeration (my counterexample is semiconductor transistor networks) I went on to elaborate that we do see nonspherical nuclei, and they get weird at orders of magnitude less ellipticity than a nucleon chain. – rob Sep 09 '14 at 03:17
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    Who is assuming that the nuclei are spheres with chaotic interiors? This is just a very rough approximation, and people who actually try to predict the stabilities and decay modes of different isotopes from theory (e.g. to look for "islands of stability") certainly don't. Nuclear shells (like electron shells) and different shapes of nuclei are standard parts of these theories. Also, nuclear physicists are quite aware that even their good theories for anything but tiny nuclei are limited by not fully using quantum chromodynamics, which is too computationally difficult right now. – Mr. Nichan Jun 26 '21 at 07:24
  • Just because Bolonkin is not fool doesn't mean we should put too much faith in his ideas, According to his biography he doesn't seem to study nuclear physics. There are examples of respectable scientists of their field making false and pseudoscientific claims on an unfamiliar one ex. : James Tour https://www.youtube.com/watch?v=SixyZ7DkSjA – spaceamoeba1010 Jul 14 '22 at 10:08