English

Exact closed-form unitary transformations of fermionic operators

Quantum Physics 2025-04-10 v2 Strongly Correlated Electrons Chemical Physics

Abstract

Unitary transformations play a fundamental role in many-body physics, and except for special cases, they are not expressible in closed form. We present closed-form expressions for unitary transformations generated by a single fermionic operator for Hermitian and anti-Hermitian generators. We demonstrate the usefulness of these expressions in formal analyses of unitary transformations and numerical applications involving block-diagonalization and Heisenberg dynamics. This work paves the way for new analytical treatments of unitary transformations and numerical many-body methods for fermions.

Keywords

Cite

@article{arxiv.2408.09636,
  title  = {Exact closed-form unitary transformations of fermionic operators},
  author = {Francesco A. Evangelista and Ilias Magoulas},
  journal= {arXiv preprint arXiv:2408.09636},
  year   = {2025}
}
R2 v1 2026-06-28T18:16:11.727Z