Weak signal amplification induced by feedback coupling in a Y-shaped chain Honghui Liu, Liqing Wu, Yage Zheng, Shanshan Cheng, Xiaoqian Liu and Lulu Lu Eur. Phys. J. Spec. Top., Publication ahead of print Published online: 21 June 2025 DOI: 10.1140/epjs/s11734-025-01725-6