对以下两位科学家进行分类：马克斯·普朗克和尼尔斯·玻尔。
Category for Max Planck and Niels Bohr: 
Max Planck: theoretical physicist, originator of quantum theory and one of the pioneers of the study of the atomic and subatomic processes. 
Niels Bohr: Danish physicist, contributed to the understanding of atomic structure and quantum mechanics, known for his model of the atomic nucleus.