Interferometric power of quantum evolutions
Phys. Rev. A 113, 052411 – Published 5 May, 2026
DOI: https://doi.org/10.1103/fmp5-9jd3
Abstract
Interferometric power (IP) quantifies the worst-case quantum Fisher information (QFI) achieved in a black-box interferometry, where the local encoding Hamiltonian has a fixed spectrum but an unknown eigenbasis. For classical-classical states as inputs for a two-qubit unitary gate, we adopt the maximum value of the symmetrized IP to quantify its IP-generation capability. Using the Cartan decomposition, our numerical results show that the unitary gates with the three-axis isotropic couplings can attain the maximum value of the symmetrized IP. Interestingly, IP is a more economical resource than quantum entanglement in adversarial sensing.
