2025/07/23 by Paul Aigner, Wolfgang Dür, Aigner, Paul +1
Computer Science · #FOS: Physical sciences #Quantum Information and Cryptography #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2507.17828
openalex publication_date 2025/07/23 · openalex created_date 2025/10/16 · openalex updated_date 2026/07/28
We investigate how unitary control can improve parameter estimation by designing the effective spectrum of the imprinting Hamiltonian. We show that, for commuting Hamiltonians, the general problem of spectral manipulation via unitary control simplifies to a finite sequence of elementary switching operations. Furthermore, we demonstrate that any desired relative spacing of energy levels can be achieved, although this may come at the cost of a reduced spectral range. We also show that any modified spectrum can be expressed as a convex combination of the original eigenvalues, with the convex weights forming a bi-stochastic matrix. Through several single-parameter estimation examples, we demonstrate that our spectral engineering method substantially enhances estimation accuracy.