Compressing Quantum Fisher Information
Quantum Physics
2026-02-11 v1
Abstract
We show that the quantum Fisher information about any phase parameter encoded in a family of pure quantum states can be faithfully compressed into a single qubit, accompanied by a logarithmic amount of classical bits. When the phase is encoded into many identical copies of a qubit state on the equator of the Bloch sphere, we show that the compression can be implemented sequentially, by iteratively compressing pairs of qubits into a single qubit. We experimentally demonstrate this building block in a photonic setup, developing two alternative compression strategies, based on Type-I fusion gate and a postselected implementation of the CNOT gate.
Cite
@article{arxiv.2602.09358,
title = {Compressing Quantum Fisher Information},
author = {Rui Jie Tang and Jeremy Guenza Marcus and Noah Lupu-Gladstein and Arthur O. T. Pang and C. Pria Dobney and Giulio Chiribella and Aephraim M. Steinberg and Y. Batuhan Yilmaz},
journal= {arXiv preprint arXiv:2602.09358},
year = {2026}
}