Diamond nanomechanics at cryogenic temperature reveals two-level-system dynamics and topological dissipation
ORAL
Abstract
Mechanical resonators form the basis of today's most sensitive measurements, from gravitational-wave detectors to atomic-scale force sensors. Yet progressing their ultimate precision has long been impeded by challenges in understanding material loss dynamics. Here, we utilize a van der Waals-strained diamond nanomechanical platform that operates at cryogenic temperature with quality factors approaching 10 billion to study the intrinsic loss origins. By sweeping temperature over four decades, we identify two distinct dissipation channels governed by two-level systems: localized surface-bond rotors and a distributed ensemble arising from lattice disorder. Surprisingly, an unexpected topological dissipation channel emerges in the dilution temperature that originates from the monolayer superfluid film at the resonator surface. These results establish strain‑engineered diamond nanomechanics as both an ultrasensitive strain sensor and a new probe of low-temperature quantum matter, bridging precision metrology and condensed matter physics.
*This work was supported by AFOSR (Grant No. FA9550-23-1-0333), AWS (Grant No. A50791). G.H. gratefully acknowledges financial support from the Swiss National Science Foundation (Postdoc.Mobility, grant number 222257), and Harvard's Aramont Fellowship for Emerging Science Research. A.M.D. acknowledges support from the Harvard Quantum Initiative Postdoctoral Fellowship in Science and Engineering and the AWS Center for Quantum Networking. N.S. acknowledges support from NSF Center for Quantum Networks (ERC EEC-1941583). This work was performed in part at the Harvard University Center for Nanoscale Systems (CNS); a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. ECCS-2025158.
