You could take a continuous path, where you have an infinite equilibrium points in between the two, a smooth path, whereyoudrop pressureand temperature simultaneosly in little increments.

你可以选择光滑的连续路径，在初末态间有,无数个平衡态的点，压强和温度同时一点,一点地下降。

麻省理工公开课 - 热力学与动力学课程节选