Microwave Photon Detection Using a Topological Josephson Junction

Abstract

Single photon detection (SPD) has found increasingly important applications in many forefront areas of fundamental science and advanced engineering applications, ranging from studying the galaxy formation though cosmic infrared background to entanglement of superconducting qubits, single molecular spectroscopy, and remote sensing. In recent years, the rapid developments in superconducting quantum computation, high fidelity quantum measurement, quantum key distribution, and quantum network call for SPD in the microwave frequency range.In this talk, I will first present our recent experimental work on topological Josephson junctions in Dirac semimetal Cd3As2. In high quality aluminum-Cd3As2-aluminum Josephson junctions, we observe both π and 4π periodic supercurrents. The π period is manifested by both the magnetic-field dependence of the critical supercurrent and the appearance of half-integer Shapiro steps in the ac Josephson effect. Our simulation by a resistively shunted junction model suggests that the π period arises from interference between the induced bulk superconductivity and the induced Fermi-arc surface superconductivity. In the second part of the talk, I will discuss microwave photon detection using these topological Josephson junctions. The temperature dependence and microwave power dependence of the junction resistance are studied. It is observed the effective temperature of the junction device under microwave radiation increases with microwave power, suggesting a promising potential for photon number-resolving capability.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under Contract No. DE-NA-0003525.