Energy Transfer Keeps the Total - Superconducting Qubits: LC Energy, Toy Josephson Coupling, and Readout Step by Step

The idealized mode swaps stores while preserving total energy. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

One snapshot stores more energy in flux

Snapshot one has capacitor energy 1/2 joule and inductor energy 2 joules.

E_C=\tfrac{1}{2}\ \text{J},\quad E_L=2\ \text{J}

A later snapshot swaps the storage emphasis

Snapshot two has capacitor energy 2 joules and inductor energy 1/2 joule, but the total is still 5/2 joules.

2+\tfrac{1}{2}=\tfrac{5}{2}\ \text{J}