Figure 1: Experimental overview.
From: Evidence for interacting two-level systems from the 1/f noise of a superconducting resonator
(a) Layout of a superconducting resonator comprising an interdigital capacitor and an inductive meander. The metallization layer is shown in grey and exposed substrate is shown in white. All dimensions are in micrometre and the lines are 4-μm wide. The resonator is inductively coupled to a coplanar feedline. (b) Conceptual model for the noise: quantum coherent TLS with energy splitting E≈ν0 acquires a width Γ2∝T1+μ because of dipole–dipole interactions with a bath of TLSs having density of states ρ(E)∝Eμ. Here μ≈0.3 and T is temperature. The resonant coherent TLSs are in turn affected by surrounding classical fluctuators strongly coupled to them that cause an energy drift, bringing the resonant TLS in and out of resonance. The LC resonator is sensitive to this energy drift and the result is a frequency shift δν, shown in the magnitude response.
