Exact chiral symmetry with quantum signal processing
arXiv:2607.28524
The paper presents a quantum signal processing algorithm that implements the overlap fermion Hamiltonian with controllable error, enabling near‑exact chiral symmetry in quantum simulations of Dirac fermions.
Abstract
We give a quantum signal processing (QSP) algorithm for the overlap fermion Hamiltonian which preserves the Ginsparg-Wilson relation up to a controllable error . Quantum simulations of Dirac fermions with exact chiral symmetry are thus nearly free: applying the overlap Hamiltonian costs only a factor logarithmic in more than the Wilson-Dirac Hamiltonian. Comparing to domain-wall fermions, a mild overhead is found in circuit complexity while reducing qubit costs. We show how QSP effectively constructs an extra dimension when simulating the overlap operator, illustrating that the scaling of quantum algorithms reflects the deeper physics of overlap fermions arising at the boundary of domain-wall fermions.
10 pages