Physics / mechanism
Neutral atom qubits trap individual atoms—typically rubidium or ytterbium—in optical tweezer arrays generated by tightly focused laser beams. Qubits are encoded in hyperfine ground states or nuclear spin (Yb-171). Entanglement uses Rydberg blockade: excite two nearby atoms to high-n states; dipole-dipole interaction suppresses double excitation, generating a controlled-Z gate. Key parameters: coherence times ~1–10 s (ground state), two-qubit gate fidelity ~99.5% (Harvard/QuEra, 2023), native mid-circuit measurement, reconfigurable connectivity. QuEra’s Aquila: 256 physical qubits; Pasqal targets 1,000 atoms by 2025; Atom Computing demonstrated 1,180-atom arrays. Error correction experiments now showing logical qubit advantage.
Competitive landscape
Competing modalities: superconducting qubits (IBM, Google)—faster gates (~50 ns vs ~1 µs), lower connectivity flexibility, dilution-fridge overhead; trapped ions (IonQ, Quantinuum)—higher fidelity, slower clock speed, hard to scale physically; photonic (PsiQuantum, Quix)—room-temp friendly, probabilistic gates. Neutral atoms differentiate on reconfigurability and qubit count scalability without proportional wiring overhead.
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.