Qiskit

Overview

Qiskit is an open-source quantum computing framework. Build quantum circuits, optimize for hardware, execute on simulators or real quantum computers, and analyze results. Supports IBM Quantum (100+ qubit Heron and Nighthawk systems), IonQ, Amazon Braket, and other providers.

Version note: Examples target Qiskit SDK 2.x (qiskit>=2,<3, Python 3.10+; current 2.5.x as of 2026-09) and qiskit-ibm-runtime ≥ 0.40 (current 0.49). Older tutorials break on these changes, so check any snippet you adapt against them:

• Qiskit 1.0 removed execute(), BasicAer, qiskit.tools (incl. tools.jupyter, job_monitor) and bind_parameters — use primitives, qiskit.providers.basic_provider.BasicSimulator, and assign_parameters.
• Qiskit 2.0 removed qiskit.pulse, BackendV1, the V1 reference primitives (qiskit.primitives.Sampler/Estimator) and Instruction.c_if (use with qc.if_test(...)).
• Qiskit 2.1 deprecated the class forms of library circuits (RealAmplitudes, EfficientSU2, TwoLocal, ZZFeatureMap, QFT, …; removal in 3.0) — use real_amplitudes(), efficient_su2(), n_local(), zz_feature_map(), QFTGate.
• Runtime V2 primitives take mode= (a backend, Session, or Batch); the old session=/backend= keywords raise TypeError. The Options class and channel="ibm_quantum" are gone — the platform is now quantum.cloud.ibm.com (API key + instance CRN, channel "ibm_quantum_platform").

When to Use This Skill

Use this skill when the user wants to:

• Build, transpile, and run gate-model circuits on IBM Quantum hardware or local simulators
• Use Qiskit Runtime primitives (SamplerV2 / EstimatorV2) in job, batch, or session mode
• Apply error suppression/mitigation (twirling, dynamical decoupling, TREX, ZNE)
• Run variational or textbook algorithms (VQE, QAOA, Grover, QPE) with the Qiskit ecosystem (Nature, Machine Learning, Optimization)