Superconducting microwave circuits show great potential for practical quantum technological applications such as quantum information processing. However, fast and on-demand initialization of the quantum degrees of freedom in these devices remains a challenge. Here, we experimentally implement a tunable heat sink that is potentially suitable for the initialization of superconducting qubits. Our device consists of two coupled resonators. The first resonator has a high quality factor and a fixed frequency whereas the second resonator is designed to have a low quality factor and a tunable resonance frequency. We engineer the low quality factor using an on-chip resistor and the frequency tunability using a superconducting quantum interference device. When the two resonators are in resonance, the photons in the high-quality resonator can be efficiently dissipated. We show that the corresponding loaded quality factor can be tuned from above 105 down to a few thousand at 10 GHz in good quantitative agreement with our theoretical model.
@article{arxiv.1712.10256,
title = {Flux-tunable heat sink for quantum electric circuits},
author = {Matti Partanen and Kuan Yen Tan and Shumpei Masuda and Joonas Govenius and Russell E. Lake and Máté Jenei and Leif Grönberg and Juha Hassel and Slawomir Simbierowicz and Visa Vesterinen and Jani Tuorila and Tapio Ala-Nissila and Mikko Möttönen},
journal= {arXiv preprint arXiv:1712.10256},
year = {2018}
}