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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.

IQM is Europe's leading quantum hardware company, having delivered 15 operational quantum systems to 13 customers across Europe, including installations at supercomputing centers in Germany (LRZ in Munich, Leibniz), Spain (CESGA), and Finland (VTT). Its 150-qubit Radiance system is designed for HPC integration. IQM is vertically integrated across the full stack — from chip design to cryogenic systems and software. The company raised over €1 billion and opened its first U.S. quantum technology center at the University of Maryland in 2025.