You won't be surprised to hear that if I take this circular magnet, in which the magnetic field is the same all around, the superconductor will be able to freely rotate around the axis of the magnet.
如果我拿出这样一个环形磁铁， 你们就不会感到惊讶， 在这个环形磁铁里，各处的磁场是相同的， 超导体能够绕着磁铁的轴线自由旋转。