Complex sentence: Therefore the total energy of the Fermi gas at Absolute zero is larger than the sum of the single-particle ground states because the Pauli principle acts as an sort of interaction/pressure that keeps the fermions sepearated and moving.
Split into simpler sentences: Therefore the total energy of the Fermi gas at Absolute zero is larger than the sum of the single-particle ground states. The Pauli principle acts as an sort of interaction/pressure that keeps the fermions sepearated and moving.