Neutral-atom qubit

A qubit stored in an uncharged atom held in a focused laser beam, an 'optical tweezer', inside a vacuum.

• Tweezer arrays hold hundreds to thousands of atoms in programmable grids; one lab has trapped over 6,000 at once.
• To interact, atoms are excited to 'Rydberg' states in which an outer electron orbits far out, making neighbours briefly and strongly coupled.
• Atoms can be physically moved mid-computation, giving flexible connections; this underpinned several logical-qubit milestones since 2023.
• Cycles are slow, around milliseconds, and atoms are lost during runs, so continuously reloading them is an active engineering problem.