Researchers are increasingly investigating the potential for hydrodynamic electron behaviour in high-mobility graphene, aiming to replicate relativistic fluid dynamics within solid-state devices. Richa P. Madhogaria, Aniket Majumdar, and colleagues from the Department of Physics, Indian Institute of Science, Bangalore, in collaboration with Kenji Watanabe and Takashi Taniguchi at the National Institute for Materials Science in Japan, have explored electron viscosity and its variability in ultra-clean graphene field-effect transistors. This study, also involving researchers from the Center for Nano Science and Engineering at the Indian Institute of Science, addresses a critical challenge in the field, the significant device-dependent variations observed in experiments…