Figure 8

Parameter spaces for a model of a domain-wall scalar field with the potential (22), interacting with (a) the electromagnetic field and (b) the electron via the quadratic-in-ϕ interactions in Eq. (17). We denote by d the size of a domain wall of cosmological origin and \(\Lambda '\) the energy scale associated with the quadratic-in-ϕ interactions between the scalar field and ordinary matter. The estimated sensitivities of clocks within the QSNET network to apparent transient variations of the fundamental constants induced by the passage of domain walls are shown by the green lines. Also shown are existing limits from previous searches for transient variations of the fundamental constants using the GPS network of clocks (brown lines) [24], and searches for quasi-static apparent variations of the fundamental constants with height above Earth’s surface using clock comparison measurements at different heights (red and yellow regions) and accelerometers (blue and cyan regions) as well as comparisons of atomic and molecular spectra in ground-based laboratory and low-density astrophysical environments (light grey regions) [27]. See the main text for more details