Nothing lasts eternally. Humans, planets, stars, galaxies, maybe even the universe itself, everything has an expiration date. But things in the quantum domain do not always follow the rules. Now scientists have discovered that quasi-particles in quantum systems could be effectively immortal.
This does not mean that they do not break down, which is reassuring. But once these quasi-particles to have decomposed, they are able to reorganize themselves in existence, eventually to infinity.
This seems to go against the second law of thermodynamics, which states that entropy in an isolated system can only move in a growing direction: things can only collapse, do not go back up.
Of course, quantum physics can become strange with the rules; but even quantum scientists did not know that quasiparticles were strange in this way.
"Until now, the hypothesis was that the quasi-particles of interacting quantum systems disintegrate after a while," said physicist Frank Pollman of the Technical University. from Munich.
"We now know that it's the opposite that happens: strong interactions can even completely stop the degradation."
Quasiparticles are not particles as we usually think, like electrons and quarks. Rather, it is the disturbances or excitations in a solid caused by electrical or magnetic forces that collectively behave like particles.
Phonons – discrete units of vibratory energy that oscillate atoms in a crystal lattice, for example – are often classified as quasi-particles, just like polarons, electrons trapped in a network surrounded by a polarization cloud.
The researchers involved in this latest study have developed numerical methods to compute the complex interactions of these quasiparticles and have run simulations on a powerful computer to observe their disintegration.
"The result of the elaborate simulation: of course, the quasiparticles break down, but new entities of identical particles emerge from the debris," said physicist Ruben Verresen from the Technical University of Munich and the Max Planck Institute for the physics of complex systems.
"If this degradation occurs very quickly, an opposite reaction will occur after a while and the debris will converge again.This process can reproduce itself at infinity and a sustained oscillation between decomposition and rebirth occurs . "
And, physicists pointed out, this would not violate the second law of thermodynamics. This is because oscillation is a wave transformed into matter, which is covered by the concept of quantum mechanics of wave-particle duality.
Their entropy does not decrease but remains constant. It's still pretty strange, but not weird.
In fact, the discovery solved two other puzzles. For example, there is a magnetic compound Ba3CoSb2O9 used in experiments that were previously found to be unexpectedly stable. It now seems that the key lies in the quasi-magnetic particles it contains, called magnons. According to the simulation, they reorganize after the degradation.
Helium is another potential example: it becomes a superfluid without resistance at a temperature of absolute zero, and this particular property could be explained by the fact that this gas is filled with quasi-particles called rotons.
For the moment, the work concerns only the theory, but the researchers think that this immortality of quasi-particles confers on him a strong potential of durable data storage in the systems of quantum computing.
The search was published in Physical Nature.