A Complete Equational Theory for Real-Clifford+CH Quantum Circuits

Alexandre Clément (Feb 09 2026).

Abstract: We introduce a complete equational theory for the fragment of quantum circuits generated by the real Clifford gates plus the two-qubit controlled-Hadamard gate. That is, we give a simple set of equalities between circuits of this fragment, and prove that any other true equation can be derived from these. This is the first such completeness result for a finitely-generated, universal fragment of quantum circuits, with no parameterized gates and no need for ancillas.

Arxiv: https://arxiv.org/abs/2602.06644