Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 99: Poster Session: Transport

TT 99.22: Poster

Thursday, March 15, 2018, 15:00–19:00, Poster B

Superconducting resonators for the study of Two-Level Systems — •Hartmut Schmidt¹, Alexander Bilmes¹, Jan Brehm¹, Shlomi Matityahu², Moshe Schechter², Alexander Shnirman¹, Georg Weiß¹, Alexey V. Ustinov^1,3, and Jürgen Lisenfeld¹ — ¹Karlsruhe Institute of Technology, Karlsruhe, Germany — ²Ben-Gurion University, Beer Sheva, Israel — ³Russian Quantum Center, Moscow, Russia

Structural material defects, so called Two-Level Systems (TLS), received much recent interest due to their detrimental effect on various micro-structured quantum devices such as qubits, photon detectors and point contacts. In this work, we present superconducting lumped element resonators that enable one to resolve single TLS in deposited dielectric materials. We apply an electric field which, in addition to strain tuning by elastic chip deformation, permits us to manipulate the TLS' resonance frequency. This specific design allows us to study the TLS behavior under strain and external electric fields as well as to obtain the coupling-strength statistics of TLSs and their density. Especially, we study the resonator loss in presence of a TLS bath that is brought out of equilibrium via an electric-field sweep. We observe increased loss at intermediate sweep rates, which we explain by a theory based on Landau-Zener transitions.