Sub-Kelvin Thermometer for On-Chip Measurements of Microwave Devices Utilizing Two-Level Systems in Superconducting Microresonators

Abstract

We present a superconducting microresonator thermometer based on two-level systems (TLS) that is drop-in compatible with cryogenic microwave systems. The operational temperature range is 50-1000~mK (which may be extended to 5~mK), and the sensitivity (50-75~$\mu$K/$\sqrt{\mathrm{Hz}}$) is relatively uniform across this range. The miniature footprint that conveniently attaches to the feedline of a cryogenic microwave device facilitates the measurement of on-chip device temperature and requires no additional thermometry wiring or readout electronics. We demonstrate the practical use of these TLS thermometers to investigate static and transient chip heating in a kinetic inductance traveling-wave parametric amplifier operated with a strong pump tone. TLS thermometry may find broad application in cryogenic microwave devices such as superconducting qubits and detectors.

References in corpus (5)

• Amplification and squeezing of quantum noise with a tunable Josephson metamaterial
• Experimental evidence for a surface distribution of two-level systems in superconducting lithographed microwave resonators
• Decoherence benchmarking of superconducting qubits
• Temperature Dependence of the Frequency and Noise of Superconducting Coplanar Waveguide Resonators
• Transmission-line resonators for the study of individual two-level tunneling systems