IBM Quantum builds on Transmon qubits: circuits built around Josephson junctions that behave as artificial atoms with quantized energy levels. Chips are cooled to near absolute zero in dilution refrigerators, and qubits are controlled and read out with microwave pulses tuned to each qubit's transition frequency.

IBM has pushed hard on qubit count, with its Condor and Heron generation chips reaching into the thousands and hundreds of qubits respectively. It publishes a public roadmap toward fault-tolerant computing, and offers cloud access to its hardware through Qiskit.