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NISQ: Noisy Intermediate-Scale Quantum Computing

Every quantum computer you can use today is a NISQ machine — large enough to resist classical simulation, noisy enough that long exact computations are out of reach. This page collects the foundational papers, error-mitigation tools, milestones and learning resources.

32 topics•5 categories•Updated October 2026

Origins & Foundational Papers

6 entries

Where the term NISQ comes from and the first results on noisy-hardware algorithms.

01Quantum Computing in the NISQ Era and Beyond (Preskill, arXiv)John Preskill's 2018 paper that coined the term NISQ. 02Quantum Computing in the NISQ Era and Beyond (Quantum journal)Published open-access version of Preskill's paper. 03Noisy Intermediate-Scale Quantum Algorithms (Bharti et al.)Review of algorithms designed for NISQ devices. 04Variational Quantum Algorithms (Cerezo et al.)Review of the hybrid algorithm family that dominates the NISQ era. 05A Variational Eigenvalue Solver on a Quantum Processor (VQE)The original VQE paper. 06A Quantum Approximate Optimization Algorithm (QAOA)The original QAOA paper.

Error Mitigation & Suppression

5 entries

Techniques that squeeze useful results from noisy hardware without full error correction.

07Error Mitigation for Short-Depth Quantum Circuits (arXiv)Temme et al. on zero-noise extrapolation and probabilistic error cancellation. 08MitiqOpen-source toolkit for applying error mitigation to quantum programs. 09Mitiq on GitHubSource code for the Mitiq error-mitigation toolkit. 10IBM – Error Mitigation and Suppression TechniquesIBM Quantum documentation on mitigation and suppression options. 11Q-CTRLQuantum control and error-suppression software.

Milestones: Utility & Error Correction

6 entries

Landmark results from the NISQ era and the first steps toward fault tolerance.

12Quantum Supremacy Using a Programmable Superconducting Processor (Nature)Google's 2019 supremacy experiment. 13Evidence for the Utility of Quantum Computing Before Fault Tolerance (Nature)IBM's 2023 result using error mitigation on a noisy processor. 14Quantum Error Correction Below the Surface Code Threshold (arXiv)Google Quantum AI's error-correction experiment. 15Quantum Error CorrectionPath from noisy physical qubits to fault-tolerant logical qubits, on this site. 16IBM Quantum Hardware and RoadmapIBM's processors and public roadmap. 17QuantinuumTrapped-ion hardware and error-correction research.

Learn & Build on NISQ Hardware

10 entries

Courses, frameworks and cloud access for running NISQ algorithms.

18IBM Quantum LearningFree courses on quantum computing and quantum algorithms. 19Quantum Computing in Practice (IBM)Course on running real quantum workloads. 20PennyLane LearnTutorials on variational algorithms and quantum machine learning. 21Qiskit Machine LearningQuantum neural networks and kernels on NISQ devices. 22Quantum CountryEssays that teach quantum computing foundations. 23Amazon BraketCloud access to superconducting, trapped-ion and neutral-atom hardware. 24Google Quantum AIGoogle's quantum hardware and Cirq framework. 25IonQTrapped-ion quantum computing company. 26RigettiSuperconducting quantum computing company. 27The Quantum Insider – NISQ GuideGuide to NISQ quantum computing from The Quantum Insider.

Related Pages & Programmes

5 entries

More quantum pages on this site and national programmes.

28Quantum ComputingHub for quantum computing topics on this site. 29Quantum Computing VendorsDirectory of quantum hardware and cloud vendors. 30Quantum Machine LearningQML resources, frameworks and papers. 31Quantum AIQuantum AI hub with variational circuits, QAOA and VQE. 32National Quantum Mission (India)India's mission on quantum computing, communication and sensing.

Frequently Asked Questions

What does NISQ mean?

Noisy Intermediate-Scale Quantum, a term John Preskill coined in 2018 for today's quantum computers: large enough to be hard to simulate classically, but noisy and without full error correction.

Why are NISQ devices noisy?

Qubits lose their state to the environment (decoherence), gates and measurements are imperfect, and neighbouring qubits interfere or must be linked through extra swap operations, so errors accumulate as circuits get longer.

What are NISQ machines used for?

Research and demonstration: hybrid algorithms such as VQE for chemistry and QAOA for optimisation, quantum machine learning experiments, and benchmarking, usually with error mitigation and many repeated shots.

How is error mitigation different from error correction?

Mitigation, such as zero-noise extrapolation, runs circuits under varied noise and extrapolates results after the fact, while error correction encodes logical qubits across many physical qubits and fixes errors during the computation.

What comes after NISQ?

Fault-tolerant quantum computers built on error-corrected logical qubits. Recent experiments show error rates falling as code size grows, but practical fault tolerance needs far more qubits than today's machines.