Janzen, Noah2022-05-022023-05-032022-05-022022-04-28http://hdl.handle.net/10012/18213One of the most ubiquitous processes in nature is the interaction of matter and an electromagnetic field which is well described using the spin-boson model. These light- matter interactions are specified by an interaction strength which is nominally fixed by nature. However, superconducting circuits are able to devise systems using microfabricated quantum devices to increase the dimensionless coupling strength α. The coupling strength is defined as α = Γ01/π∆ where Γ01 is the decay rate and ∆ is the transition frequency of the system. As the strength increases and the rate of interaction approaches the frequency of the system, the light-matter interactions enter the ultra-strong coupling (USC) regime where α ∼ 0.1. Approximations that are often made to simplify the spin-boson model begin to break down in the USC regime making the analysis of these systems challenging. We demonstrate a flux tunable coupler with potential to explore these dynamics by coupling a persistent current qubit (PCQ) as artificial atom to an open transmission line (TL) as source of continuous bosonic modes. The tunable coupler is able to both decouple the PCQ from the TL as well as enable the USC regime of interactions with a coupling range spanning from αmin = 2.4 × 10−4 to αmax = 1.2 × 10−1. The future objective is to directly explore the time-domain properties of the USC regime and to open new research approaches to relativistic quantum information (RQI) by using the tunable coupler as a switching function.enultra-strong couplingrelativistic quantum informationlight-matter interactionflux qubitsuperconducting circuittunable couplerMaster Thesis