Tunable superconducting resonators, subharmonic oscillations and manipulation of microwaves
Doktorsavhandling, 2018

In this thesis I present different types of manipulations of microwave fields using tunable superconducting resonators. A resonator is made tunable by adding one or more superconducting quantum interference devices, SQUIDs. The SQUID consists of a superconducting loop with two Josephson junctions and acts as a tunable nonlinear inductor. Modulation of the SQUID nonlinearity can be performed to induce different types of non-trivial oscillator dynamics.

The first project I present is on subharmonic oscillations. Here, the SQUID in a tunable resonator is driven with an external signal at an integer multiple of the frequency w. When w is placed slightly below the first resonator mode, I show generation of radiation at w, which is known as frequency down-conversion. In my measurements, subharmonic oscillations have been detected from period doubling up to period quintupling. For the specific case of period tripling, theory is developed and I show good agreement between theory and experiments.

The second project of the thesis is on a doubly tunable resonator. Here, I show creation of a superconducting resonator with two independently tunable boundary conditions. The idea with this system is to operate the resonator in a breathing or a translational mode and compare the two. For static dc magnetic flux the performance is very good. As a second step, I perform fast modulation of both SQUIDs to generate radiation. Even though some of the measurement results are promising, I also show some contradicting observations. These indicate that the actual modulation mechanism of the SQUID is not pumping of the magnetic flux in the SQUID loop as intended, but rather direct current driving of the SQUID. However, the system remains a promising idea for microwave manipulation and creation of interesting non-classical states.

As a possible application of the doubly tunable resonator, I present a theory proposal on how to use it for measurements on relativistic effects. By using the tunability of the resonator boundary conditions, the resonator can simulate a space rocket and time dilation could be measured. However, due to the crosstalk problems in the doubly tunable resonator this experiment was never realized.

Finally, I finish the thesis by presenting a design for a tunable microwave coupling. Papers E and F show a high on-off ratio for the coupler and demonstrate how it can be used for storage of microwave signals. Furthermore, the tunable coupler can be used to shape a microwave signal by tuning the strength of the coupling.

driven nonlinear systems


microwave manipulation

parametric oscillations

superconducting resonator

frequency down-conversion

tunable resonator


subharmonic oscillations

Kollektorn, MC2
Opponent: Prof. P. J. Meeson, Department of Physics, Royal Holloway, University of London, United Kingdom


Ida-Maria Svensson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Period-tripling subharmonic oscillations in a driven superconducting resonator

Physical Review B,; Vol. 96(2017)p. 174503-

Artikel i vetenskaplig tidskrift

Svensson, I-M., Bengtsson, A., Bylander, J., Shumeiko, V., Delsing, P. Period multiplication in a parametrically driven superconducting resonator

Svensson, I-M., Pierre, M., Simoen, M., Wustmann, W., Krantz, P., Bengtsson, A., Bylander, J., Shumeiko, V., Delsing, P. Microwave photon generation in a doubly tunable superconducting resonator

Twin paradox with macroscopic clocks in superconducting circuits

Physical Review A - Atomic, Molecular, and Optical Physics,; Vol. 90(2014)p. Art. no. 052113-

Artikel i vetenskaplig tidskrift

Storage and on-demand release of microwaves using superconducting resonators with tunable coupling

Applied Physics Letters,; Vol. 104(2014)p. Art. Nr. 232604-

Artikel i vetenskaplig tidskrift

Pierre, M., Sathaymoorty, S., Svensson, I-M., Johansson, G., Delsing, P. Resonant and off-resonant microwave signal manipulations in coupled superconducting resonators


Nanovetenskap och nanoteknik




Den kondenserade materiens fysik



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4372


Chalmers tekniska högskola

Kollektorn, MC2

Opponent: Prof. P. J. Meeson, Department of Physics, Royal Holloway, University of London, United Kingdom