And in the current issue of Applied Physics Letters, a group led by Haroun Ahmed at the Hitachi Cambridge Laboratory in Britain reports another vital step, a single-electron transistor that, for the first time, amplifies its input signal (though only by a factor of 3.7, several hundred times more weakly than a conventional transistor does).

ECONOMIST: The transistor��s heir

But the two researchers have already used them to make a simple, disposable memory circuit, which they will describe in a forthcoming issue of Applied Physics Letters.

ECONOMIST: A new use for a common material