Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 99: Poster Session: Transport

TT 99.21: Poster

Donnerstag, 15. März 2018, 15:00–19:00, Poster B

Readout sensitivity of mechanical motion in inductively coupled nano-electromechanical devices
— •P. Schmidt^1,2,3, C. Utschick^1,2, D. Schwienbacher^1,2,3, L. Rosenzweig^1,2, N. Segercrantz^1,2, F. Deppe^1,2,3, A. Marx^1,2, R. Gross^1,2,3, and H. Huebl^1,2,3 — ¹Walther-Meißner-Institut, BAdW, Germany — ²Physik-Department, TUM, Germany — ³Nanosystems Initiative Munich, Germany

In recent years nano-electromechanics have demonstrated mechanical ground state cooling and the preparation of nonclassical states employing the linearized opto-mechanical interaction. However, the optomechanical coupling constant g₀ denoting the single photon - single phonon coupling rate has remained small compared to the cavity decay rate.

Here, we present an inductively coupled electromechanical system in contrast to the typically capactitively coupled mechanical elements. To this end, we place a dc-SQUID with a mechanical string resonator at the current anti-node of a superconducting microwave resonator. The electromechanical coupling is realized via the change of the SQUID loop area caused by the displacement of the string. Hereby, the coupling is increased as it is levered by the non-linear Josephson junctions of the dc-SQUID, approaching the resonator decay rate.

We focus on challenges related to the non-linearity of the microwave resonator. In particular, we compare the displacement noise of the thermal motion of the string resonator with the imprecision and the backaction noise imposed by the measurement.