While non-Hermitian systems exhibit extraordinary phenomena like exceptional points, their complete characterization has remained elusive, hindered by the inability to directly probe left eigenvectors (LEVs). This study marks a significant advancement by introducing and experimentally validating a novel methodology to directly measure LEVs in non-Hermitian systems using non-Hermitian Green's functions. We demonstrate this breakthrough approach on two distinct non-Hermitian acoustic models, successfully characterizing their topological properties. By enabling direct access to LEVs, our work addresses a critical gap in non-Hermitian physics research, which has predominantly focused on right eigenvectors. This capability provides profound insights into non-Hermitian topology and unlocks pathways for designing next-generation devices, such as highly sensitive topological sensors and efficient single-mode lasers. Our results thus offer a fundamental new tool for exploring and harnessing the unique physics of non-Hermitian platforms. For more details, please refer to the article entitled “Experimental measurement of non-Hermitian left eigenvectors” by Xulong Wang and Guancong Ma. [Front. Phys. 20(5), 054202 (2025)]. [Photo credits: Xulong Wang & Guancong Ma at Hong Kong Baptist University]
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