Mohammad Masoumi

Pauli Decomposition by Character Theory: A Memory-Bounded Algorithm for Qubits and Qudits

Pauli decomposition underpins Trotterization, phase estimation, sparse-Hamiltonian simulation, and variational observables, at exponential naive cost. From the character theory of $(\mathbb{Z}_2)^n$, characters $\chi_z(v)=(-1)^{\langle v,z\rangle}$ are the diagonal Pauli strings, so any diagonal operator is already Pau...