In September 2025, IonQ announced that its Tempo system had achieved AQ 64 (Algorithmic Qubits) three months ahead of schedule. Tempo uses approximately 100 physical qubits and represents a key threshold: at AQ 64, the state space has 2⁶⁴ dimensions, so classical computers can no longer fully simulate the system.

AQ is IonQ's metric for "useful" qubits — the maximum N for which an N-qubit circuit with N² entanglement gates achieves at least 37% fidelity on standard benchmarks (QFT, Hamiltonian simulation, Monte Carlo sampling). Tempo also set a world record for 2-qubit gate fidelity at 99.99%.

Source: https://www.ionq.com/news/ionq-achieves-record-breaking-quantum-performance-milestone-of-aq-64