【摘要】 本文讨论并计算了量子情况下磁场中三维电子气体系的熵，发现存在磁场时三维电子气体系的熵有可能大于无磁场时的熵。从而证明了对于在外场下的量子体系Baierlein认为对所有的热力学体系，体系的熵总是随外场或粒子间相互作用的引入而减小的观点不成立。更多还原

【Abstract】 The effects of external fields on the entropy of Fermi systems was discussed. As an example, the entropy of a certain quantum system, the 3D charged Fermions system in the magnetic field has been calculated. It is found that the entropy of the 3D charged Fermions system in the magnetic field could be larger than that of a same system without magnetic field. This result disproved Baierlein’s idea that the entropy of any thermal system will decrease when external fields or the particle interactions applied.更多还原