Original title: Tunable topological enhancement of covariant quantum Fisher information via non-Bloch skin effect in non-Hermitian SSH lattices
Qi-Cheng Wu, Yan-Hui Zhou, Tong Liu, Dong-Xu Chen +1 · September 2026
Scientists want to make quantum sensors as precise as possible, but previous work on a key precision benchmark called covariant quantum Fisher information only examined single-mode systems. In this study, researchers expanded this benchmark to larger, multi-mode grid structures called non-Hermitian Su-Schrieffer-Heeger lattices. They discovered that an effect known as the non-Hermitian skin effect bunches waves toward the system edges when the boundaries are left open. This wave-bunching dramatically boosts measurement precision compared to sensors with looped, periodic boundaries. The total precision scales with system size, and the boost holds up against moderate local disorder. It also allows devices to measure multiple parameters at once with vastly better accuracy. Finally, researchers can test this approach using real circuits and light-based setups available today.
Imagine you are trying to hear someone whisper outside a long hallway. If the hallway is a circle with open windows all around, the sound arrives from every direction and no single spot stands out. But if the hallway is a straight corridor with a solid wall at one end, the sound waves that reach the wall accumulate there, making the whisper distinctly louder at that spot. In this paper, quantum sensors arranged in an open line instead of a closed loop cause their collective quantum behavior to concentrate at one boundary, making the whole array dramatically better at detecting tiny signals.
Quantum sensors are central to precision measurement in physics and beyond. This work shows that simply changing the physical layout of a sensor array — from a closed loop to an open line — can boost precision by over 30 times for the same number of sensors. It offers a new design knob for experimentalists building quantum sensing devices, using technology that already exists in laboratories.
The enhancement exceeding 30-fold is demonstrated only for system sizes up to about 30 sensors; behavior at much larger scales is not detailed. Robustness is verified only against moderate local disorder, not severe disorder. The work is theoretical with no experimental implementation reported in this abstract. The abstract does not specify how the enhancement factor itself scales with system size beyond N ~ 30.
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Tunable topological enhancement of covariant quantum Fisher information via non-Bloch skin effect in non-Hermitian SSH lattices — Qi-Cheng Wu, Yan-Hui Zhou, Tong Liu et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.