TC

導體由普通狀態向超導態轉變時的温度稱為超導體的轉變温度，或臨界温度，用

（critical temperature）表示．

In physics, chemistry, thermodynamics, statistical mechanics (統計力學), quantum field theory (量子場論), and condensed matter physics, a critical point, also called a critical state, specifies the conditions (temperature, pressure and sometimes composition) at which a phase boundary ceases to exist. There are multiple types of critical points such as vapor–liquid critical points and liquid–liquid critical points.