Exact closed-form expression for unitary spin-adapted fermionic singlet double excitation operators
Quantum Physics
2025-05-05 v1
Abstract
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 ansatze 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.
Keywords
Cite
@article{arxiv.2505.00883,
title = {Exact closed-form expression for unitary spin-adapted fermionic singlet double excitation operators},
author = {Erik Rosendahl Kjellgren and Karl Michael Ziems and Peter Reinholdt and Stephan P. A. Sauer and Sonia Coriani and Jacob Kongsted},
journal= {arXiv preprint arXiv:2505.00883},
year = {2025}
}