Neutral Atom Qubit

A neutral-atom qubit encodes information in the internal energy states of a single uncharged atom, held in a vacuum chamber by a tightly focused laser beam called an optical tweezer. Because tweezers are generated and repositioned optically, arrays of hundreds to thousands of atoms can be rearranged into arbitrary geometries between circuit steps, an advantage no other modality has natively. Two-qubit gates are implemented by briefly exciting a pair of atoms into a Rydberg state, in which their electron orbits swell enough that neighboring atoms block each other's excitation (the Rydberg blockade), and that blockade is what generates entanglement. QuEra, Pasqal, and Atom Computing all build on this modality. Gate fidelities have historically trailed trapped-ion and superconducting qubits, though recent results have narrowed that gap, and atom loss (an atom escaping the tweezer mid-circuit) remains a distinct error channel that other modalities do not share.