When an electron drops back from an excited to an unexcited state, it gives out light.

ECONOMIST: Optoelectronics

Bombard an ordinary hydrogen atom with microwaves of the right frequency and you will lift it out of its ground state by flipping the spin of its electron.

ECONOMIST: Are matter and antimatter truly opposites?

Konstantin Likharev, at the State University of New York at Stony Brook, a co-inventor of the single-electron transistor, is working on ways to combine it with conventional transistors to make super-dense memory chips.

ECONOMIST: The transistor��s heir