Neutral-Atom Systems
Neutral-atom machines hold individual uncharged atoms in focused laser beams (optical tweezers) and entangle nearby atoms through the Rydberg blockade — a strong, distance-limited interaction that makes the array's geometry itself the connectivity graph. Atoms can even be moved mid-computation, trading routing gates for shuttling time.
What is a neutral-atom machine?
A neutral atom is an ordinary, uncharged atom — commonly rubidium, caesium, strontium or ytterbium in these machines. With no net charge, the electromagnetic traps that hold ions get no grip on it. The tool instead is the optical tweezer: a laser beam focused to a spot so tight that a single atom is attracted to, and held at, the focus — a pair of tweezers made of light.
One laser, split by a programmable beam-shaping element, becomes hundreds or thousands of tweezers at once, each holding one atom. The result is an array of qubits whose positions are set by software: grids, triangles, rings — almost any 2D pattern (3D has been demonstrated too). Arrays of several hundred to over a thousand trapped atoms exist today; note that is a count of trapped atoms, which is not the same claim as that many simultaneously high-fidelity computing qubits.
As with ions, the qubit lives in two stable internal states of the atom, and every atom of the same isotope is identical — no fabrication variation.
You’ve read the opening of chapter 5 — 6 more sections follow, with worked examples and circuits you can run on the page. A free account unlocks every chapter of every course (paid plans aren’t live yet — early readers get everything free).