Quantum Computing Challenges Holding Back Practical Quantum Computers

Quantum computing still faces major hardware, error correction, scaling, software and workforce challenges before it can support commercially valuable applications. High error rates and decoherence limit current quantum processors, while fault-tolerant systems require large numbers of physical qubits and significant advances in control, cooling, wiring and manufacturing. Limited quantum algorithms, immature software tools and a shortage of specialized workers add further constraints as the industry moves toward fault-tolerant quantum computing. Quantum computing has attracted billions in investment, sustained media attention, and some of the most concentrated scientific talent on a single engineering problem. Progress has been significant, but the results so far have yet to match the scale of investment and research behind the field. To date, no quantum computer has outperformed a classical computer on a commercially valuable problem. Current systems operate in what researchers call the Noisy Intermediate-Scale Quantum (NISQ) era, characterized by devices with enough qubits to demonstrate quantum behavior but too much noise to run useful algorithms reliably. The gap between where the hardware is and where it needs to be is not a matter of incremental improvement. It involves solving several distinct problems, each of which is difficult on its own and harder in combination.…