Josephson Current through a Quantum Dot Connected with Superconducting Leads

Figure 6

Dependence of the critical current on the QD energy level for and . (a) U = 0. (b) HF approximation. (c) Lacroix approximation. The solid, dashed, and dotted curves correspond to cases U = 5, 8, and 10, respectively. (d) Component of . U = 8 and the data are obtained by the Lacroix approximation. The solid, dashed, and dotted curves represent , , and , respectively.

(a)

(b)

(c)

(d)