Testing the electric Aharonov-Bohm effect with superconductors

Understand

The phase of the wave function of charged matter is sensitive to the value of the electric potential, even when the matter never enters any region with non-vanishing electromagnetic fields.

• Despite its fundamental character, this archetypal electric Aharonov-Bohm effect has evidently never been observed.
• We propose an experiment to detect the electric potential through its coupling to the superconducting order parameter.
• A potential difference between two superconductors will induce a relative phase shift that is observable via the DC Josephson effect even when no electromagnetic fields ever act on the superconductors, and even if the potential difference is later reduced to zero.