What Is NISQ Quantum Computing: The Current Era of Quantum Machines

Insider Brief

• NISQ, or Noisy Intermediate-Scale Quantum, describes current quantum computers that can run quantum algorithms but remain limited by noise, error rates and circuit depth.
• NISQ systems are primarily used for research and experimentation, including testing quantum algorithms, error mitigation techniques and hybrid quantum-classical approaches.
• The industry is beginning to move toward fault-tolerant systems through advances in quantum error correction, although NISQ hardware remains the dominant category of commercially available quantum computers.

Every quantum computer commercially available today belongs to the same category. Whether it is IBM‘s quantum systems, Google‘s superconducting processors, or IonQ‘s trapped-ion hardware. All of these are NISQ devices, whether the press releases say so or not.

NISQ stands for Noisy Intermediate-Scale Quantum. Physicist John Preskill coined the term in 2018 to describe machines that are large enough to be difficult to simulate on classical computers, but too error-prone to run complex algorithms that would make quantum computing commercially transformative. The label has become standard across the industry because it accurately describes where quantum hardware is.