Electrons in a superconductor form Cooper pairs and thus condense into a ground state which can be described by a macroscopic quantum wavefunction. The phase of the wavefunction represents a collective movement of millions of Cooper pairs.

• 超导体中的电子结成库珀对；凝聚到可以用一个宏观波函数来描绘的能量基态；该波函数的位相是代表了成百万库珀对集体运动的宏观变量.