Negative-Inductance Superconducting Quantum Interference Device With Energy Dissipation of 1.38 zJ/bit Measured by Inductively Coupled Coplanar Waveguide Resonator

High energy-efficient superconducting circuits are increasingly desirable for information technology. Negative-inductance superconducting quantum interference device (nSQUID) is considered to have the capability of approaching the physical limit of irreversible computing. Superconducting coplanar waveguide (CPW) resonator of high quality factor Q is widely used for detecting extremely small signals. To measure the energy dissipation in nSQUID, we have designed and fabricated an nSQUID with its common mode flux control inductively coupled to a superconducting CPW resonator. The energy dissipation can be obtained from the changes in transmission spectra of the coupled circuit at different input powers. Low temperature experimental results at 1.07 K show that the bit operation energy in nSQUID operating at 2.19 GHz is about 1.38 zJ.