Charge Qubit Coherence in a Double Quantum Dot

A single electron shared between two tunnel-coupled quantum dots forms one of the simplest real qubits: its two charge states, "electron in the left dot" and "electron in the right dot," coherently oscillate into one another at a rate set by the interdot tunnel coupling and the electrostatic detuning between the dots. This simulator renders that double-dot potential landscape in 3D and animates the electron's probability weight swinging between the two wells, while a live oscilloscope trace and ensemble-averaged charge-noise model show why real charge qubits are operated at the "sweet spot" — the detuning value where the qubit's frequency is first-order immune to the electrical noise that otherwise destroys coherence in nanoseconds.