A superconducting contact is like a narrow bridge between two shores, carrying current without friction. Place such a bridge near a massive star, and it will feel time flowing slower near the star's surface. Clocks on the shores tick at different rates, and the current begins to oscillate differently.
But if the star rotates slowly, the picture gets more complicated. The space around it is not just curved: it's also twisted, like water swirling down a drain. It turns out that this twist barely affects the oscillation frequency. Instead, it shifts the phase of the wave, as if the bridge were slightly turning.
For superconducting circuits in space, this means: if you need to measure time or phase precisely, you'll have to account for the fact that space doesn't stand still. A circuit sensitive to phase shifts will reveal the star's rotation, while one sensitive to frequency will reveal its mass.
The Sagnac effect, which arises from rotation, is used in aircraft laser gyroscopes: they sense the Earth's rotation beneath the wing.
In the movie 'Interstellar,' the characters encounter time dilation near a black hole — here it's the same effect, but for superconducting currents.