In the quantum-mechanical description, matter at absolute zero is in its ground state, the point of lowest internal energy. Absolute zero, temperature at which a thermodynamic system has the lowest energy. It corresponds to −273.15 °C on the Celsius temperature scale and to −459.67 °F on the Fahrenheit temperature scale. Absolute temperature is temperature measured using the Kelvin scale where zero is absolute zero. The zero point is the temperature at which particles of matter have their minimum motion and can become no colder.