Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 17: Superconductivity: Qubits II

TT 17.7: Vortrag

Montag, 12. März 2018, 16:30–16:45, H 2053

Tunable ohmic environment using Josephson junction chains — •Gianluca Rastelli¹ and Ioan M. Pop² — ¹Zukunftskolleg & Fachbereich Physik, Universität Konstanz, Konstanz, Germany — ²Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

We analyse a scheme to implement a tunable resistance using a double chain of Josephson junctions. The two parallel chains are formed by N dc-SQUIDs, acting as linear and tunable inductance L. The chains are coupled capacitively through a capacitance C much larger than the capacitance of the individual dc-SQUID. The system sustains electromagnetic modes forming a large but discrete set of damped harmonic oscillators. This set yields an impedance Z, that is a smooth and continuous function versus frequency. Moreover, the system can be connected to an external measurement setup, and the dissipation can be continuously monitored. We show that, by varying L, the double chain can operate as tunable ohmic resistance in a frequency band spanning several GHz, with a resistance that can exceed the quantum resistance. We argue that the circuit complexity is within reach using current Josephson junction technology.