Digital quantum simulation for spin and fermionic systems


qat.fermion is a revamped and improved version of the now deprecated qat.dqs module.
To update your code, please refer to the detailed changelog detailed changelog.

This is the reference documentation for the qat.fermion module. Its aim is to provide tools for describing and solving spin and fermionic problems. The code of qat.fermion is open-source and part of the myQLM suite. The source code can be found here.

This includes, among others:

  • objects to help you define fermionic and spin Hamiltonians,

  • spin-to-fermion transformations, such as Jordan-Wigner, Bravyi-Kitaev or parity basis transformations,

  • variational quantum eigensolver (VQE) tools, including a module to construct a UCC ansatz,

  • tools aimed at atomic and molecule studies (active space selection, basis transformations,…etc),

  • a trotterization module,

  • a quantum phase estimation module,

  • an adaptative ansatz VQE plugin (ADAPT-VQE),

  • a natural gradient-based optimizer,

  • a sequential hybrid classical-quantum optimizer,

  • a zero noise extrapolator plugin for multiqubit noise mitigation,

qat.fermion features have been broken down into three parts.

We also provide the following Jupyter notebooks:

  • The source code documentation is available here.

  • The changelog is available here.