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Qiskit

What is it​

Qiskit is an open-source quantum computing framework maintained by IBM. It is written in Python (with performance-critical pieces in Rust) and is the most widely used quantum SDK, with a large community, extensive documentation, and a deep learning catalog. Its focus is general-purpose gate-model quantum computing: circuit construction, transpilation/optimization, simulation, and execution on real IBM Quantum systems.

Since Qiskit 1.0 the API has stabilized around the QuantumCircuit class, the primitives (Sampler and Estimator), and a clear separation between circuit building and execution.

Install​

pip install qiskit qiskit-aer
  • qiskit — core SDK (circuits, transpiler, primitives).
  • qiskit-aer — high-performance local simulators.

To run on real hardware you also install and configure qiskit-ibm-runtime with an IBM Quantum account.

Hello Quantum​

A Bell state 12(∣00⟩+∣11⟩)\frac{1}{\sqrt{2}}\left( \lvert 00 \rangle + \lvert 11 \rangle \right) measured on the local AerSimulator:

from qiskit import QuantumCircuit
from qiskit_aer import AerSimulator
from qiskit import transpile

# Build a 2-qubit Bell state
qc = QuantumCircuit(2, 2)
qc.h(0)          # superposition on qubit 0
qc.cx(0, 1)      # entangle qubit 0 with qubit 1
qc.measure([0, 1], [0, 1])

# Run on the local Aer simulator
sim = AerSimulator()
compiled = transpile(qc, sim)
result = sim.run(compiled, shots=1024).result()

print(result.get_counts())
# e.g. {'00': 503, '11': 521}

You should see only 00 and 11 outcomes (up to statistical noise), confirming the two qubits are entangled.

Strengths & use cases​

  • Maturity and community. The largest user base, most tutorials, and richest Q&A history of any quantum framework.
  • Transpilation. A powerful, configurable transpiler that maps abstract circuits onto a device's native gate set and connectivity.
  • Real hardware. First-class access to IBM Quantum systems through Qiskit Runtime primitives.
  • Pulse and low-level control. Fine-grained control of IBM devices when you need it.
  • Education. A natural default for courses and self-study.

Ecosystem​

  • Qiskit Aer — local high-performance simulators (statevector, density matrix, stabilizer, noisy).
  • Qiskit IBM Runtime — execution layer for IBM hardware with Sampler/Estimator primitives.
  • Qiskit Nature, Qiskit Optimization, Qiskit Machine Learning, Qiskit Finance — application-domain modules.
  • Qiskit Transpiler / mthree — circuit optimization and measurement error mitigation.

Resources​

Ready to build? See the labs, or plan a study path in the roadmaps.