Ket Quantum Programming

Ke is a high-level quantum programming platform for writing, simulating, and executing quantum algorithms in Python, without sacrificing performance or control.

  • 🧠 Expressive quantum language embedded in Python

  • ⚙️ High-performance runtime written in Rust

  • 📄 Backed by peer-reviewed research

Ket bridges the gap between quantum theory, software engineering, and efficient execution, enabling researchers, students, and developers to build quantum-accelerated software with clarity and confidence.

Aprenda Ket 🇧🇷

A complete Portuguese course is available at aprenda.quantumket.org, covering linear algebra, quantum mechanics, and quantum algorithms, with hands-on examples using Ket.

What is Ket?

Ket is a full quantum programming platform designed to make quantum development concise, readable, and efficient. It allows you to express quantum algorithms using familiar Python syntax while relying on an optimized runtime and simulators behind the scenes.

Ket applications communicate with the runtime library Libket, and Libket communicates with the quantum simulator KBW Ket applications communicate with the runtime library Libket, and Libket communicates with the quantum simulator KBW

The platform consists of three main components:

  • Ket (Python Package)

    A Python-embedded quantum language that provides only the essential abstractions required for expressive and efficient quantum programming.

    • Minimal and explicit quantum constructs

    • Designed for algorithm clarity

    • Ideal for education and research

  • Libket (Runtime Library)

    A high-performance runtime library written in Rust, responsible for compilation, optimization, and execution of quantum programs.

    • Used transparently by Ket

    • Also accessible directly via C or Rust APIs

  • KBW (Ket Bitwise Simulator)

    A noise-free quantum simulator for executing quantum programs on classical hardware.

    • Dense and sparse simulation methods

    • CPU and GPU-accelerated backends

Getting Started

Installation

Ket requires Python 3.10 or newer and supports Linux, Windows, and macOS (Apple Silicon and Intel).

Install Ket directly from the Python Package Index (PyPI) using pip:

python3 -m pip install ket-lang

Note

On non-x86_64 Linux or Windows systems (e.g., ARM), Rust is required to build native components.

Your First Quantum Program

Create and simulate a Bell state in just a few lines of Python:

from ket import *

p = Process()
a, b = p.alloc(2)

CNOT(H(a), b)

print(dump(a + b).show())

Run the program using:

$ python3 bell.py
|00⟩        (50.00%)
0.707107            ≅      1/√2
|11⟩        (50.00%)
0.707107            ≅      1/√2

This example demonstrates superposition, entanglement, and state inspection using Ket.

Simulation Backends

Ket includes multiple simulators with different performance characteristics, allowing you to choose the best option for your workload.

  • "sparse" Sparse simulator with limited multithreading support.

  • "dense" Dense state-vector simulator with good multithreaded performance.

  • "dense v2" Dense simulator with a reduced memory footprint.

  • "dense gpu" GPU-accelerated dense simulator supporting Intel, AMD, Apple, and NVIDIA GPUs. Recommended for simulations with a large number of qubits.

Tip

Benchmarking is recommended to determine the most suitable simulator for a given algorithm.

Research & Publications

Ket is an academically grounded platform with multiple peer-reviewed publications describing its language design, runtime architecture, and compilation strategies.

Evandro Chagas Ribeiro Da Rosa and Rafael De Santiago. 2022. Ket Quantum Programming. J. Emerg. Technol. Comput. Syst. 18, 1 (January 2022), 1-25. https://doi.org/10.1145/3474224

Evandro C. R. Rosa, Eduardo I. Duzzioni, and Rafael De Santiago. 2025. Optimizing Gate Decomposition for High-Level Quantum Programming. Quantum 9, (March 2025), 1659. https://doi.org/10.22331/q-2025-03-12-1659

Evandro C. R. Rosa, Jerusa Marchi, Eduardo I. Duzzioni, and Rafael De Santiago. 2025. Quantum Gate Decomposition: A Study of Compilation Time vs. Execution Time Trade-offs. In Anais do XXIX Simpósio Brasileiro de Linguagens de Programação (SBLP 2025), September 22, 2025. Sociedade Brasileira de Computação, Brasil, 10-18. https://doi.org/10.5753/sblp.2025.10459

Evandro Rosa, Eduardo Lussi, Jerusa Marchi, Rafael De Santiago, and Eduardo Duzzioni. 2026. Full Quantum Stack: Ket Platform. Braz J Phys 56, 1 (February 2026), 45. https://doi.org/10.1007/s13538-025-01981-w

@article{ket2022,
    title = {Ket Quantum Programming},
    volume = {18},
    issn = {1550-4832, 1550-4840},
    url = {https://dl.acm.org/doi/10.1145/3474224},
    doi = {10.1145/3474224},
    language = {en},
    number = {1},
    urldate = {2026-01-08},
    journal = {ACM Journal on Emerging Technologies in Computing Systems},
    author = {Da Rosa, Evandro Chagas Ribeiro and De Santiago, Rafael},
    month = jan,
    year = {2022},
    pages = {1--25},
}

@article{ket2025a,
    title = {Optimizing Gate Decomposition for High-Level Quantum Programming},
    doi = {10.22331/q-2025-03-12-1659},
    volume = {9},
    issn = {2521-327X},
    language = {en},
    urldate = {2026-01-08},
    journal = {Quantum},
    author = {Rosa, Evandro C. R. and Duzzioni, Eduardo I. and De Santiago, Rafael},
    month = mar,
    year = {2025},
    pages = {1659},
}

@inproceedings{ket2025b,
    title = {Quantum Gate Decomposition: A Study of Compilation Time vs. Execution Time Trade-offs},
    doi = {10.5753/sblp.2025.10459},
    urldate = {2026-01-08},
    booktitle = {Anais do XXIX Simpósio Brasileiro de Linguagens de Programação (SBLP 2025)},
    address = {Brasil},
    publisher = {Sociedade Brasileira de Computação},
    author = {Rosa, Evandro C. R. and Marchi, Jerusa and Duzzioni, Eduardo I. and Santiago, Rafael De},
    month = sep,
    year = {2025},
    pages = {10--18},
}

@article{ket2026,
    title = {Full Quantum Stack: Ket Platform},
    doi = {10.1007/s13538-025-01981-w},
    volume = {56},
    issn = {0103-9733, 1678-4448},
    language = {en},
    number = {1},
    urldate = {2026-01-08},
    journal = {Brazilian Journal of Physics},
    author = {Rosa, Evandro and Lussi, Eduardo and Marchi, Jerusa and De Santiago, Rafael and Duzzioni, Eduardo},
    month = feb,
    year = {2026},
    pages = {45},
}

Used in Research

Ket has been used in peer-reviewed research across optimization, simulation, and feedback-based quantum algorithms.

Otto Menegasso Pires, Rafael De Santiago, and Jerusa Marchi. 2021. Two Stage Quantum Optimization for the School Timetabling Problem. In 2021 IEEE Congress on Evolutionary Computation (CEC), June 28, 2021. IEEE, Kraków, Poland, 2347-2353. https://doi.org/10.1109/CEC45853.2021.9504701

Letícia Bertuzzi, João P. Engster, Evandro C. R. Da Rosa, and Eduardo I. Duzzioni. 2025. Shadow measurements for feedback-based quantum optimization. Phys. Rev. A 112, 2 (August 2025), 022419. https://doi.org/10.1103/snht-7jsf

Ket API Documentation

ket

Ket Quantum Programming Platform.
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