Investigating a challenge of building a superconducting quantum computer.

Parasitic two-level systems (TLS) coupling to a superconducting quantum circuit causes information loss. To mitigate this problem, a better physical understanding of the coupling mechanism is crucial. Phase noise caused by TLS interaction is investigated by using a surface acoustic wave resonator. The results show a significant correlation of resonance frequency fluctuations between different resonance modes, supporting the prediction of the TLS model.