Magnetic Flux Quantum as a Sub-pico-Newton Weight

摘要

We suggest flux quantum-based force realization in the sub-pico-Newton range. By controlling the number of fluxquantum in a superconducting ring, a force can be created as an integer multiple of a constant force step. For a 70 nm-thick Nb ring with the inner and outer radii of 5 (mu)m and 10 (mu)m, respectively, the force step is estimated to be 186 fN, assuming the magnetic field gradient of 10 T/m. We also estimated a maximum force limit and addressed the stability of force realization against thermal fluctuation.