For more than 40 years, physicists could not explain the behavior of "strange metals", which at strong cooling behaved differently from ordinary metals. If in ordinary metals there was superconductivity and instantly disappeared at some clear temperature mark, the resistance of strange metals at a change in temperature changed linearly. There was no intelligible explanation for this until it was recently done by physicists from the USA.
A comprehensive justification of the theory of behavior of strange metals - metals that do not obey the theory of Fermi-liquid - made the project leader Aavishkar Patel (Aavishkar Patel) from the Center for Computational Quantum Physics (CCQ) Flatiron Institute in New York and physicists Haoya Guo, Ilya Esterlis and Subir Sachdev from Harvard University. At the very least, the scientists have substantiated a number of characteristic properties of "strange metals." The slender theory may help answer questions about achieving superconductivity at high temperatures and aid in the development of quantum computers. Quantum mechanics was the tool that helped to unravel the question.
The new theory relies on two key properties of strange metals. First, electrons in such metals can become entangled with each other - moving into completely identical quantum states - and remain in that state even when they are far apart. Second, the strange metals have an inhomogeneous, patchwork-like arrangement of atoms.
"None of these properties individually explain the strangeness of 'strange metals', but together everything falls into place," explained the head of the project.
The irregularity of the atomic structure of the strange metal means that electron entanglement depends on where in the material it occurred. This variety introduces randomness into the momentum of the electrons as they move through the material and interact with each other. Instead of flowing together, the electrons collide with each other in all directions, resulting in electrical resistance. Since electrons collide more frequently the hotter the material, electrical resistance increases with temperature, which is what is observed in practice. Where ordinary metals have a jump in the transition from superconductivity to a sharp increase in resistance, strange metals continue to carry current with a smooth increase in resistance to current.
The key to the new theory is that physicists have combined two phenomena - entanglement and inhomogeneity, which was not previously considered for a single material, and separately it does not lead to strange behavior of metals. By doing so, the scientists propose a mechanism to correct the conditions of superconductivity in strange metals. Artificially created inhomogeneities could reproduce superconductivity in the right place for the right purpose, which could find applications in quantum computers, for example. When you can influence something, it's capable of producing the desired result.
"There are cases where something wants to go into a superconducting state but can't do so because superconductivity is blocked by another competing state," Patel says. - One might then wonder if the presence of these inhomogeneities could destroy these other states with which superconductivity competes and leave the way open for superconductivity."