Observation of a superfluid-to-insulator transition of bilayer excitons - Yihang Zeng; Dihao Sun; Naiyuan J. Zhang; Ron Q. Nguyen; Qianhui Shi; A. Okounkova; K. Watanabe; T. Taniguchi; J. Hone; C. R. Dean; J. I. A. Li (Nature, 2026)