Fig. 2: Tunneling spectroscopy results of the single and coupled JJs.

a Tunneling spectroscopic result of the single JJL as a function of B. The SC gap oscillates to B, which is assigned to the feature of ABS expected in short JJs. b Tunneling spectroscopic result of the single JJR. Almost the same features as in the JJL result are found. The periodicity of the ABS oscillation is the same as that in (a) because the two loops hold the same area. The white dashed lines indicate the B points giving the minimal SC gap. The red, blue, and green tags on the top axes of (a) and (b) indicate B = 0.230, 0.273, and 0.295 mT, respectively. c Tunneling spectroscopic result of the JJL coupled with JJR. The result is drastically modulated from the single JJ case in (a). Especially, the SC gap becomes minimal away from \({\phi }_{{{\mbox{L}}}}={\phi }_{{{\mbox{R}}}}={{{{{\rm{\pi }}}}}}\) where the gap becomes minimal in the single JJ cases. d Tunneling spectroscopic result of the JJR coupled with JJL. The same features observed in (c) were acquired. The consistency between (c) and (d) assures that the AMSs are constructed due to the coherent coupling of the two JJs. e \({G}_{{{\mbox{L}}}}\) vs. V at B = 0.230, 0.273, and 0.295 mT, respectively, measured for the single JJL. f \({G}_{{{\mbox{R}}}}\) vs. V measured for the single JJR. g \({G}_{{{\mbox{L}}}}\) vs. V measured for the coupled JJL. The SC gap is closed at B = 0.273 mT while the other two curves hold the SC gap. h \({G}_{{{\mbox{R}}}}\) vs. V measured for the coupled JJR. As with the coupled JJL case, the SC gap is closed at B = 0.273 mT while the other two curves hold the SC gap.