Many anticipated discoveries in fundamental science demand better measurement sensitivity. For acoustic sensors, mechanical dissipation sets this limit via the fluctuation-dissipation theorem. Yet, even in high-purity crystals, its microscopic origin remains poorly understood, and external enhancement, such as tension-induced dissipation dilution, is difficult to realize. Here, we realize a strain-engineered diamond nanomechanical platform using van der Waals self-assembly that harnesses surface forces to apply tensile stress exceeding 1 GPa. At cryogenic temperatures, these resonators achieve quality factors beyond 10^10. This exceptional coherence allows us to resolve residual dissipation channels, elucidating distinct two-level systems and topological dissipation from a surface superfluid helium film. Advancing mechanical coherence therefore opens access to new regimes of physics in hybrid quantum systems, precision metrology, and condensed-matter physics.
The Physics Frontiers Centers (PFC) program supports university-based centers and institutes where the collective efforts of a larger group of individuals can enable transformational advances in the most promising research areas. The program is designed to foster major breakthroughs at the intellectual frontiers of physics by providing needed resources such as combinations of talents, skills, disciplines, and/or specialized infrastructure, not usually available to individual investigators or small groups, in an environment in which the collective efforts of the larger group can be shown to be seminal to promoting significant progress in the science and the education of students. PFCs also include creative, substantive activities aimed at enhancing education, broadening participation of traditionally underrepresented groups, and outreach to the scientific community and general public.