Strong Radiation-Matter Interaction in a Driven Superconducting Quantum System

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Linnanmaa, lecture room L7

Topic of the dissertation

Strong Radiation-Matter Interaction in a Driven Superconducting Quantum System

Doctoral candidate

Master of Science Iivari Pietikäinen

Faculty and unit

University of Oulu Graduate School, Faculty of Science, Nano and Molecular Systems Research Unit (NANOMO)

Subject of study

Theoretical physics

Opponent

Professor Zaki Leghtas, Mines ParisTech

Custos

Professor Erkki Thuneberg, University of Oulu

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Strong radiation-matter interaction

In my thesis we studied strong interaction between radiation and matter in superconducting electric circuits. Typically this interaction is investigated in systems consisting of electric fields and single atoms. With the electric circuits one can accomplish stronger coupling between the radiation and matter.

This research was done with a system consisting of waveguide resonator coupled to a transmon qubit. Qubit is a quantum mechanical two-state system. The waveguide resonator was driven to higher energy state with a strong voltage. For weak driving the system behaves quantum mechanically and for strong driving classically. The research focused on the region between the quantum limit and the classical limit.

We showed that, as the system is driven from the quantum regime to the classical one, also the higher states of the transmon device are important. Also, we compared the Floquet-Born-Markov method that we used to a commonly used Linndbald master equation method. The results from both methods were very close but the Floquet-Born-Markov method was much faster.
Last updated: 18.4.2019