Sword of Damocles | by Brian Koberlein



9 September 2014

In line with legend, when Damocles declared that his king, Dionysius, will need to have a fancy and straightforward life, Dionysius supplied to commerce locations with Damocles. There was just one catch. Dionysius decreed {that a} sword be suspended over the throne by a single horse hair, in order that Damocles would at all times know the peril of being king. Since then the Sword of Damocles has come to signify a menace of doom that would strike with out warning. Whereas the prospect of residing beneath a dangling sword doesn’t appear nice, tales of impending doom are fairly well-liked, notably inside well-liked science.

Once in a while some science information story will hit the press trumpeting the newest Damocles sword. Large asteroid may wipe out life on Earth! Close by supernova may kill us all! Photo voltaic flares may destroy civilization! Geomagnetic reversal! Rogue black holes! And on and on. The newest doomsday information to hit the press stems from a declare by Stephen Hawking that the existence of the Higgs boson implies that the universe may spontaneously collapse at any second. Recreation over, Man! Recreation over!

Like most such hype, the true story is each much less sensational and extra fascinating. All of it begins with a long-known property of quantum mechanics, that quantum programs don’t at all times must settle of their most secure configuration. They’ll as a substitute discover themselves in a domestically secure state (often known as a metastable state). We see this, for instance, with electrons in an atom. The secure state of an electron in an atom is its lowest potential power degree, however an electron could be in a better power degree for some time. Finally it may well drop to a decrease power degree, which releases a photon. This impact is why we see line spectra in stars and interstellar clouds.

Measures of the top quark vs Higgs boson masses, compared to stability calculations.
Sean Carrol
Measures of the highest quark vs Higgs boson plenty, in comparison with stability calculations.

With the invention of the Higgs area, one query we will ask is whether or not the universe as a quantum system it’s in a secure, low-energy state, or in a metastable increased power state. In line with the usual mannequin of particle physics, the reply relies upon upon the plenty of the highest quark and the Higgs boson. The extra large the Higgs boson, the extra probably the universe is to be secure. The extra large the highest quark, the extra probably the universe is to be metastable, and even unstable. From our present measurements of the highest and Higgs plenty, it appears that evidently our universe is metastable.

If our understanding is appropriate, then the universe as an entire may very well be in a domestically secure configuration, nevertheless it may additionally soar to a decrease power state by means of a technique of quantum tunneling. If that occurred, the universe would collapse and we’d all go bye bye. So to our greatest understanding, it’s potential for the universe to break down. In fact by the identical course of it’s also potential that for those who run towards a wall the atoms in your physique will quantum tunnel by means of the wall and also you’ll end up on the opposite facet. The probabilities of that really occurring is negligible at finest.

In fact if the universe have been too secure, that would result in different issues, reminiscent of the concept that we are literally simply Boltzmann brains. Being metastable may really be a very good factor somewhat than an indication of impending doom.

So there’s no have to cancel your trip plans, or cease saving for retirement. Even when there’s a cosmic sword of Damocles, the quantum thread holding it’s a lot stronger than you would possibly suspect.

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