Complex sentence: This quantity is important in transport phenomena such as the Mott relations for electrical conductivity and thermoelectric coefficient for an electron gas, where the ability of an energy level to contribute to transport phenomena is proportional to\\ langle (\\ Delta N) ^ 2\\ rangle.
Split into simpler sentences: This quantity is important in transport phenomena such as the Mott relations for electrical conductivity and thermoelectric coefficient for an electron gas. The ability of an energy level to contribute to transport phenomena is proportional to\\ langle (\\ Delta N) ^ 2\\ rangle.