Closed-Form Expressions for Unitaries of Spin-Adapted Fermionic Operators

• URL: http://arxiv.org/abs/2505.02984v1
• Date: Mon, 05 May 2025 19:27:06 GMT
• Title: Closed-Form Expressions for Unitaries of Spin-Adapted Fermionic Operators
• Authors: Ilias Magoulas, Francesco A. Evangelista,
• Abstract summary: We analyze the mathematical structure of spin-adapted operators and derive closed-form expressions for unitaries generated by singlet spin-adapted generalized single and double excitations.<n>These results represent significant progress toward the economical enforcement of spin symmetry in quantum simulations.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: One of the open challenges in quantum computing simulations of problems of chemical interest is the proper enforcement of spin symmetry. Efficient quantum circuits implementing unitaries generated by spin-adapted operators remain elusive, while na\"ive Trotterization schemes break spin symmetry. In this work, we analyze the mathematical structure of spin-adapted operators and derive closed-form expressions for unitaries generated by singlet spin-adapted generalized single and double excitations. These results represent significant progress toward the economical enforcement of spin symmetry in quantum simulations.

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