This continues my previous multiverse-related questions.

There are some particles that could be useful to the scientific industry if they did not decay so quickly, such as antimatter-matter composites, some unstable isotopes and the like. In most cases, they decay as fast as they are created in our world.

However, I wonder if in a parallel universe, if the strong force interactions were different than they were in our world, would it be likely that such isomers and composites that were initially easily decayed in our world could be more stable in that world, or even metastable? Would it have to be stronger or weaker than it is? (Though may be more of the latter)

More importantly, assuming we are advanced enough to even traverse to parallel universes, could we successfully take these isomers and composites back to our world safely without any issues happening?

PS: Also, note that I got the idea of metastable alternate-universe materials that is caused by a difference in strong force from Asimov's the Gods Themselves. Namely his Plutonium-186. There are other types of odd isomers in sci fi that could be useful without the decaying problem, such as Hydrogen-4 (Quantium) and Caesium-138. Maybe even Naquadah in the Island of Stability.

  • $\begingroup$ antimatter-matter composites? Are you sure they exist? $\endgroup$
    – L.Dutch
    Jun 15, 2020 at 6:17
  • $\begingroup$ positronium exists, but it is the simplest possible composite. $\endgroup$
    – Whitecold
    Jun 15, 2020 at 6:22
  • 1
    $\begingroup$ Do you mean mesons (quark and anti quark)? note they must be of same flavour to annihilate. $\endgroup$
    – user6760
    Jun 15, 2020 at 6:41

4 Answers 4


There are several parts to the question:

  • antimatter-matter composites won't become any more stable, since protons and anti protons will still annihilate, increasing the strong force will only make them interact even faster
  • Gamma and alpha decay will be suppressed, since you are raising the potential barrier
  • Beta decay is mediated by the weak force, so these will be unaffected

However, any universe with vastly different force constants will likely not have any interesting matter in it at all, since either everything will collapse, or everything expanding without stars ever forming. Neither option is very appealing, so your wiggle room in the constants is rather small.

I very much doubt you can achieve meta-stability with it, since metastable states usually are metastable because the transition is forbidden to some degree; This depends on the quantum numbers of the states in question, and not the coupling strength.


So some people have already done the calculations, turns out the biggest problem is not unstable things becoming stable, but stable isotopes becoming unstable. In this paper the authors discuss what happens to deuterium (it becomes unstable) which alters stellar evolution and what stars would look like (though they claim that you could still make life in this universe). There is also this paper by a similar set of authors looking at the changes in the weakforce.


Its easier than going to another universe.

In proper field theory forces are mediated by exchange particles, and the density of exchange particles can be altered using different environments (often called the "density of states"). https://en.wikipedia.org/wiki/Density_of_states

You can very approximately, think of this as an extension of that cartoon where you imagine particle anti-particle pairs just appearing and disappearing at random in the vacuum. If this were happening then you could use lenses and mirrros to make these random fluctuations more concentrated at some locations and frequencies than others. So that the reactions these virtual particles trigger happen faster or slower.*

In modern nanotech experiments it is not at all strange for people to speed up, or slow down, the rate at which unstable quantum states decay via photon emission (by building an environment, usually with mirrors, that alters the photon density of states).

Most often people go the opposite direction to the one you are describing: they engineer environments that make unstable states die faster (called "Purcell enhancement"). https://en.wikipedia.org/wiki/Purcell_effect#:~:text=The%20Purcell%20effect%20is%20the,given%20by%20the%20Purcell%20factor

Often this is done using photonic crystals (https://en.wikipedia.org/wiki/Photonic_crystal)

So, in order to stabilise strange exotic things that decay via photon emission, all you really need is to propose that in the future people become very good at making mirrors. If they instead want to stabilise things that decay due to the strong or weak nuclear forces then you just need to propose that your future-people have invented mirrors for the strong and weak force carriers.

* Note that idea of particles and their opposites just appearing at random and then disappearing again is really not to be taken seriously as a theory or a real picture of what is "actually" happening. It is a cartoon.


As a slightly different tweak on your metastability idea would be to look at compounds of materials. There are a lot of compounds that are metastable and are useful. For example diamond can now be synthesized by chemical vapor deposition at low pressures and temperatures, but doesn't revert back to graphite even though it is thermodynamically unstable.

In a parallel universe perhaps you could synthesize other useful substances that are not thermodynamically stable enough to be useful in this universe. I'm not sure what might be the most compelling from a story point of view, but for example you could have the rearrangement of the atoms from one crystal lattice into another crystal lattice. Or perhaps you could have new materials where instead of atoms going back into lattice sites of a crystal you can create materials with lots of atomic voids in them making materials less dense for example. Take every other atom out of a metal crystal for example and let it still be stable. Although that might also be extremely reactive.


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