Exact closed-form expressions for unitary spin-adapted fermionic singlet double excitation operators
We derive exact closed-form expressions for the matrix exponential of the anti-Hermitian spin-adapted singlet double excitation fermionic operators. These expressions enable the efficient implementation of such operators within unitary product state frameworks targeting conventional hardware and allow for the implementation of ansätze that guarantee convergence to specific spin symmetries. Moreover, these exact closed-form expressions might also lay the groundwork for constructing spin-adapted circuits for quantum devices.
Authors
- Erik Rosendahl Kjellgren (ORCID: https://orcid.org/0000-0002-8489-3496)
- Karl Michael Ziems (ORCID: https://orcid.org/0000-0001-5369-7778)
- Sonia Coriani (ORCID: https://orcid.org/0000-0002-4487-897X)
- Peter Reinholdt (ORCID: https://orcid.org/0000-0003-2406-700X)
- Stephan P. A. Sauer (ORCID: https://orcid.org/0000-0003-4812-0522)
- Jacob Kongsted (ORCID: https://orcid.org/0000-0002-7725-2164)
Institutions
- University of Copenhagen (DK)
- University of Southern Denmark (DK)
- University of Southampton (GB)
- IT University of Copenhagen (DK)
- Technical University of Denmark (DK)
Publication Details
- Journal
- The Journal of Chemical Physics
- Published
- 2025-10-03
- DOI
- https://doi.org/10.1063/5.0278717
- Primary Topic
- Quantum Computing Algorithms and Architecture
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Novo Nordisk
- Novo Nordisk Fonden