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arXiv · 2602.09358

Compressing Quantum Fisher Information

Rui Jie Tang·Jeremy Guenza Marcus·Noah Lupu-Gladstein·Arthur O. T. Pang·C. Pria Dobney·Giulio Chiribella·Aephraim M. Steinberg·Y. Batuhan Yilmaz
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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.

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Rui Jie Tang, Jeremy Guenza Marcus, Noah Lupu-Gladstein, Arthur O. T. Pang, C. Pria Dobney, Giulio Chiribella, Aephraim M. Steinberg, Y. Batuhan Yilmaz. 2026-02-10. Compressing Quantum Fisher Information. https://arxiv.org/abs/2602.09358

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