- Andreev Reflection in Superfluid He-3: A Probe for Quantum Turbulence

Bradley et al., Annual Review of Condensed Matter Physics Vol. 8: 407-430 (2017) - Operating Nanobeams in a Quantum Fluid

Bradley et al., Nature Scientific Reports**7**, 4876 (2017) - Single Quantum Level Electron Turnstile

D.M.T. Van Zanten et al., Phys. Rev. Lett.**116**166801 (2016) - Topological Superconductivity and High Chern Numbers in 2D Ferromagnetic Shiba Lattices

J. Röntynen, T. Ojanen, Phys. Rev. Lett.**114**236803, (2015) - Squeezing of Quantum Noise of Motion in a Micromechanical Resonator

J.-M. Pirkkalainen et al., Phys. Rev. Lett**115**, 24 (2015) - Direct-current superconducting quantum interference devices for the readout of metallic magnetic calorimeters

S. Kempf, A. Ferring, A. Fleischmann, C. Enss, Supercond. Sci. Technol.**28**, 045008 (2015)

## Wideband superconducting nanotube electrometer

*P. Häkkinen, A. Fay, D. Golubev, P. Lähteenmäki, P. Hakonen*

We have investigated the microwave response of nanotube Josephson junctions at 600â€“900â€‰MHz at microwave powers corresponding to currents from 0 to 2â€‰Ã—â€‰I C in the junction. Compared with theoretical modeling, the response of the junctions corresponds well to the lumped element model of resistively and capacitively shunted junction. We demonstrate the operation of these superconducting FETs as charge detectors at high frequencies without any matching circuits. Gate-voltage-induced charge Q G modifies the critical current I C, which changes the effective impedance of the junction under microwave irradiation. This change, dependent on the transfer characteristics dI C/dQ G, modifies the reflected signal and it can be used for wide band electrometry. We measure a sensitivity of 3.1Ã—10âˆ’5â€‰e/Hzâˆš from a sample which has a maximum switching current of 2.6â€‰nA.

*Appl. Phys. Lett.*

**107**1, 1-4doi:

*10.1063/1.4926400*