Variational Algorithms for Quantum Chemistry with Tequila

Recording of a talk I gave at the Chemistry-Departments seminar at TU Braunschweig, July 2022:

slides

Some slides contain small code examples. These slides are taken from a Tequila tutorial that can be found here.

These are the explicit files containing those examples (file names in the lower right corner of the corresponding slide):

• example_objective.py
• example_nested_objective
• ch4.py

Tequila codebase and tutorials can be found here (see also below for explicit links): github.com/tequilahub.

Relevant Papers:

• Tequila Overview paper: arxiv:2011.03057
• Automatically Differentiable Unitary Coupled-Cluster: arxiv:2011.05938 (applications to Adaptive Solvers and Excited States):
• Basis-Set-Free VQEs: arxiv:2008.02819
• Separable Pair Approximations: arXiv:2105.03836 (compact and classically simulable quantum circuits)
• Directly Determined PNOs: JCP:10.1063/1.5141880 (the machinery that runs in the back of the Basis-Set-Free VQE and the tequila madness interface - not on arxiv but I can send you the pdf :-))
• Overview of Unitary Coupled-CLuster: arXiv:2109.15176

Relevant tequila tutorials (in NBViewer):

• basic usage: General how-to for tequila
• basis-set-free H2 toy code: Minimal qubit Hamiltonian of H2 in basis-set-free representation. If you don’t have time and just want one molecule.
• SPA ansatz: Examples for the SPA ansatz and a collection of precomputed basis-set-free representations of molecules (if you don’t want to compile madness).
• madness-interface: If you want to compute your own molecular orbitals from scratch.