Flux-tunable heat sink for quantum electric circuits

M Partanen; K Y Tan; S Masuda; J Govenius; R E Lake; M Jenei; L Grönberg; J Hassel; S Simbierowicz; V Vesterinen; J Tuorila; T Ala-Nissila; M Möttönen

doi:10.1038/s41598-018-24449-1

Flux-tunable heat sink for quantum electric circuits

Sci Rep. 2018 Apr 20;8(1):6325. doi: 10.1038/s41598-018-24449-1.

Authors

M Partanen¹, K Y Tan², S Masuda², J Govenius², R E Lake^{2

3}, M Jenei², L Grönberg⁴, J Hassel⁴, S Simbierowicz⁴, V Vesterinen^{2

4}, J Tuorila^{2

5

6}, T Ala-Nissila^{4

7

8}, M Möttönen⁹

Affiliations

¹ QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland. matti.t.partanen@aalto.fi.
² QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland.
³ National Institute of Standards and Technology, Boulder, Colorado, 80305, USA.
⁴ VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044, VTT, Finland.
⁵ MSP group, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland.
⁶ Nano and Molecular Systems Research Unit, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland.
⁷ Departments of Mathematical Sciences and Physics, Loughborough University, Loughborough, Leicestershire, LE11 3TU, United Kingdom.
⁸ Department of Physics, Brown University, Box 1843, Providence, Rhode Island, 02912-1843, USA.
⁹ QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland. mikko.mottonen@aalto.fi.

Abstract

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.