Toy Josephson Coupling

Coupling Sign Changes the Energy Direction

A signed flux source fixes the sign of the toy coupling. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Changing flux sign changes the energy sign

The current stays 3 amperes, but the flux is -2 webers.

3 A⋅−2 Wb=−6 J3\ \text{A}\cdot -2\ \text{Wb}=-6\ \text{J}
Signed couplingThe sign is derived from signed flux.current=3 Aflux=-2 WbcouplingFactor=1couplingEnergy=-6 J

A label cannot choose the sign

The checked toy energy is -6 joules because the flux source is negative.

Etoy=−6 JE_{\text{toy}}=-6\ \text{J}
Signed sourceA stale positive energy would fail validation.current=3 Aflux=-2 WbcouplingFactor=1couplingEnergy=-6 J