QSimulate

IBM operates the world's largest fleet of cloud-accessible quantum systems through the IBM Quantum Network, serving over 300 organizations. Its superconducting qubit roadmap has progressed from the 127-qubit Eagle (2021) through the 1,121-qubit Condor to the current 156-qubit Heron processor, which achieved a 16x performance improvement over 2022 systems. IBM's open-source Qiskit SDK is the most widely used quantum programming framework globally. The company targets a 200-logical-qubit system (Starling) by 2028 using LDPC codes that it claims require 90% fewer physical qubits than surface codes.

Google Quantum AI operates from a dedicated campus in Santa Barbara, California, and achieved a landmark result in late 2024 when its Willow chip demonstrated below-threshold quantum error correction for the first time — proving that adding more qubits reduces rather than increases errors. This was widely regarded as the most significant QEC milestone to date. Google's open-source Cirq framework is used for circuit-level quantum programming. The team has published extensively on quantum supremacy (Sycamore, 2019) and continues to advance superconducting qubit coherence times and gate fidelities.

Rigetti is a publicly traded pure-play quantum computing company that designs and manufactures superconducting quantum processors in its own fabrication facility — one of only a few quantum companies with in-house fab capability. Its current Ankaa-2 system (84 qubits) uses tunable couplers and a square lattice for 98% median two-qubit gate fidelity. Rigetti also sells QPUs directly through its Novera product line, and offers cloud access via Amazon Braket and Azure Quantum. In collaboration with Riverlane, it demonstrated real-time low-latency quantum error correction in 2024.

Formed from the 2021 merger of Honeywell Quantum Solutions and Cambridge Quantum Computing, Quantinuum leads the world in logical qubit count and trapped-ion fidelity. Its Helios system (launched November 2025) offers 98 physical and 48 logical qubits using barium atoms, and is available via cloud and on-premises installation. Early users include JPMorgan Chase, SoftBank, Amgen, and BMW. Quantinuum was valued at $10 billion as of 2025 and is backed by Honeywell, which retains majority ownership. It also develops TKET, a widely-used open-source quantum compiler.