| Summary: | <p>This thesis presents an effort towards integration of superconductor-contacted carbon nanotubes into microwave circuits, as a new tool for building quantum circuits. Carbon nanotubes show a wealth of quantum phenomena demonstrated in transport experiments by different groups in the last two decades. With the development of circuit QED, one can study these phenomena using on-chip microwave circuits. Moreover, in superconductor-contacted nanotubes, Andreev reflection of the particles at the interfaces leads to the formation of Andreev bound states. A pair of such states can potentially serve as a new type of a qubit.</p> <p>Here, fabrication and measurement techniques of superconductor contacted carbon nanotubes and superconductor/normal metal bilayer microwave circuits is developed, and their behaviour is studied.</p> <p>In superconductor-contacted nanotubes the full range of contact transparencies is investigated, showing different transport phenomena such as Coulomb blockade, Kondo effect and Fabry-Pérot interference. In addition, the interplay of these effects with multiple Andreev reflection phenomena and the superconducting proximityinduced non-dissipative current transport through the nanotube is studied.</p> <p>The proximity effect is studied using microwave resonators made of superconductor/ normal metal bilayers. Characteristic parameters of the bilayers, such as the critical temperature and the magnetic penetration depth are reliably extracted from the measurements.</p> <p>Finally, the two experiments are brought together in the first step towards using superconductor-contacted nanotubes in quantum microwave circuits. The successful realization of such circuit is achieved, where the Coulomb blockade in a nanotube quantum dot is probed with a microwave field.</p>
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