Got Mass? Scientists Observe Electrons Become Both Heavy and Speedy
princeton.edu
Electrons moving in certain solids can behave as if they are a thousand times more massive than free electrons, but at the same time act as superconductors. A new study led by Princeton scientists shows that this happens because of a process known as quantum entanglement that determines the mass of electrons moving in a crystal. The discovery can help improve understanding of how certain materials become superconducting, which may have applications in areas such as power network efficiency and computing speed. (Image by the Yazdani Group)
A Princeton University-led team of scientists has shown how electrons moving in certain solids can behave as though they are a thousand times more massive than free electrons, yet at the same time act as speedy superconductors.
The observation of these seemingly contradictory electron properties is critical to the understanding of how certain materials become superconducting, in which electrons can flow without resistance. Such materials could dramatically increase the efficiency of electrical power networks and speed up computers.
The concept of “heavy” electrons seems counterintuitive. The tiny particles flit through silicon chips to process information rapidly in digital electronics, and they flow with ease through copper wires carrying electricity to your desk lamp. But the Princeton research has revealed that a hard-to-measure process known as quantum entanglement determines the mass of electrons moving in a crystal and the delicate tuning of this entanglement can strongly alter the properties of a material.
Cool the electrons to far below room temperature in certain types of solid materials, and these flighty particles gain mass, acting like much heavier particles. Surprisingly, further cooling close to absolute zero makes these solids become superconducting, where the electrons, despite their heaviness, make a kind of perfect fluid that can flow without wasting any electrical power.