Low temperature 1/f noise in microwave dielectric constant of amorphous dielectrics in Josephson qubits
Abstract
The accurate analytical solution for the low temperature 1/f noise in a microwave dielectric constant of amorphous films containing tunneling two-level systems (TLSs) is derived within the standard tunneling model including the weak dipolar or elastic TLS-TLS interactions. The results are consistent with the recent experimental investigations of 1/f noise in Josephson junction qubits including the power law increase of the noise amplitude with decreasing temperature at low temperatures T<0.1K. The long time correlations needed for 1/f noise are provided by the logarithmic broadening of TLS absorption resonances with time due to their interaction with neighboring TLSs. The noise behavior at higher temperatures T>0.1K and its possible sensitivity to quasi-particle excitations are discussed.