So, I have been a bit disappointed with the answers on how to store degenerate matter from my previous thread, and now I'm even wondering whether one can produce it at all, without invoking unrealistic femtotechnology.

As everyone knows, to even convert regular matter into degenerate matter, requires insane amounts of pressure. Unfortunately, regular materials would certainly break after a certain amount of pressure, and the highest pressure generated in laboratory conditions is only 770 GPa (from a diamond anvil).

I came across this forum full of nuclear physicists, who realise that to make successful nuclear reactions which actually generate energy, they need electron degenerate matter, which can be used to emulate a Type Ia Supernova.

I understand well that protons fuse very very slowly (and don't get much faster either with greater compression or with CNO cycle), which means that ordinary stars can last for billions of years but that a fusion reactor using only common isotopes of hydrogen sounds difficult to achieve useful power outputs from unless it was the size of a small stellar core, even if we had Dr. Minkovsky helping us out with containment.

However, I also understand that in a type Ia supernova, "cold" gas is compressed so tightly that it becomes electron-degenerate, and that if enough additional gas is added, a portion of it eventually "flashes" to fusion very rapidly, forming a spectacular and rapid explosion. The power density is on the very, very, very rough order of 10E13 times that of the sun.


Image showing atoms and then nucleons compressed under various pressures

As shown here, the compression required is around 1 ton per square centimeter, not as bad as say, neutronium or quark matter. If we have theoretical strong and utterly fireproof materials (i.e. AB-Matter, Starlite, Muonic Metals, Monopolium; only slightly unobtainium; the last two are also REAL DENSE) for the compressing machine, could electron degenerate matter be created with enough pressure?

If not, then is there any possible method of generating electron degenerate matter?

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    $\begingroup$ Note that the pressure you're looking at there is lower than that developed in synethetic diamond anvils... they can hit 5.5GPa, which is ~55 tonnes per square centimetre, and diamonds ain't electron degenerate. As HDE 226868 points out, temperature is also important. $\endgroup$ Commented Jan 19, 2020 at 11:11
  • $\begingroup$ Also, starlite is not magic. It is not "utterly fireproof", and the rest are hardly "only slightly unobtanium". $\endgroup$ Commented Jan 19, 2020 at 11:12
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    $\begingroup$ (also also, thermonuclear bombs have "actual gain" and we've been making them for decades without recourse to electron degenerate matter). $\endgroup$ Commented Jan 19, 2020 at 11:17
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    $\begingroup$ Although this isn't strictly key to the question, I'd like to echo @StarfishPrime's points about the materials used for compression: Starlite is likely a hoax, and "AB matter" cannot exist because of the electrostatic forces between nucleons. $\endgroup$
    – HDE 226868
    Commented Jan 20, 2020 at 2:05

1 Answer 1


Use low temperatures.

For a given system, we can tell if degeneracy pressure is important by comparing the Fermi energy $E_F$ to the thermal energy $kT$. if $E_F\gg kT$, the gas is fully degenerate; even $E_F\sim10kT$ will apparently lead to at least partial degeneracy. As the Fermi energy scales as $E_F\propto \rho^{2/3}$, and (non-relativistic) degeneracy pressure scales as $P\propto\rho^{5/3}$, where $\rho$ is density, it should be clear that if your substance is quite cold, you can achieve degeneracy at lower pressures.

Consider a gas of electrons (not a gas in the usual sense) at $T\sim 10\text{ K}$. This has a thermal energy of $kT\approx8.6\times10^{-4}\text{ eV}$. Let's assume that full degeneracy occurs at a Fermi energy of $E_F\approx100kT$. This requires a surprisingly low density - only $\rho\approx1.05\times10^{-7}\text{ g cm}^{-3}$. Calculating the degeneracy pressure shows that $P\sim10\text{ Pa}$, which is clearly substantially easier to achieve.

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    $\begingroup$ Excellent job pointing out that low temperatures are the only realistic way to get a degenerate electron system outside of stars. However, the thermal energy of an electron at 10K has the sign wrong on power (-4 not 4). The density is in the ballpark, but with an important caveat; this is true for electrons in a conduction band. I'm sure you're aware of this, but for readers who might not know, these electrons must be within a material, this is not a gas in the traditional sense or else the electromagnetic interaction would obliterate the need for degeneracy of states $\endgroup$
    – user110866
    Commented Apr 14, 2020 at 22:22
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    $\begingroup$ @user110866 Thanks for the correction - looks like I just made a typo rather than a calculation error. $\endgroup$
    – HDE 226868
    Commented Apr 14, 2020 at 22:31

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