Probing two-level systems with a surface acoustic wave resonator
Typ
Examensarbete för masterexamen
Program
Publicerad
2021
Författare
Tubsrinuan, Nuttamas
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Parasitic two-level systems (TLSs) cause detrimental effects on the performance
of superconducting quantum devices. To mitigate this problem, a better physical
understanding of the TLS coupling mechanism is crucial. In this thesis, a new approach
for probing TLSs using a surface acoustic wave (SAW) resonator is presented.
Having a small mode spacing, the SAW resonator enables an investigation of the
frequency noises caused by TLSs at many different frequencies simultaneously.
We report a novel result of the correlated frequency noise caused by TLSs. The
correlations of the noise diminish with increasing detuning, which is in agreement
with the prediction of the TLS model. However, the frequency noises also show
negative correlations, which cannot be explained by the current physical model. Additionally,
the frequency noise correlation between different modes shows a power
and temperature-dependent behavior. Although some previous experiments have
reported the power and temperature dependence of the frequency noise spectra,
the relationships of the noise at several different frequencies have not been studied.
Therefore, further investigations, both experimental and theoretical aspects, of the
multifrequency noise beyond this work are required.
Beskrivning
Ämne/nyckelord
two-level system, surface acoustic wave, SAW resonator, resonance frequency fluctuation, tunneling model, frequency noise, correlation, frequency comb