Werner Karl Heisenberg was born on December 5, 1901, in Würzburg, Germany. His father, August, was a professor of Greek philology, his mother, Annie, an intelligent and caring homemaker. In many ways, his family fit the typical bourgeois mold of the time, placing an emphasis on respectability and social grace–values that Heisenberg would soon begin to question. Also, at an early age, Heisenberg was encouraged to compete, especially with his brother, which instilled in him a drive to succeed that would characterize his entire career. The brothers were encouraged to compete even in music, and Heisenberg developed a lifelong passion for the piano, which often served as a calming influence.
Heisenberg's formative years took place against the backdrop World War I, and in the beginning he may have been caught up in romanticizing warfare, though he would face inevitable disillusionment. After the war, he and many of Germany's youth were left feeling lost and confused. In response, Heisenberg joined various youth movement groups that provided him with a sanctuary. The focus of these groups was not activism; rather, it gave groups of boys the opportunity to discuss philosophy, bond, and find new forms of idealism to replace others that had been destroyed by the war. As a group leader, Heisenberg served as a father figure for many younger boys, and he continued to go on retreats into the 1930s.
The war had no small impact on Heisenberg's schooling: he attended the elite Maximilians-Gymnasium, of which his grandfather was rector. Many school resources were cut back and classes disrupted, but Heisenberg managed to advance far beyond his curriculum, at least in math and physics. After graduating with recognition as one of the top students in Bavaria, he attended Munich and, almost by default, ended up studying with Ernest Sommerfeld. Sommerfeld was not only a great mentor who truly supported his students, but he would lobby for Heisenberg throughout his career, naming him as his heir apparent (though Nazi opponents would thwart this plan).
Under Sommerfeld, Heisenberg constructed his core model of the atom, which answered many of the current puzzles while also discarding cherished principles of quantum theory, including some of the work of Sommerfeld and Niels Bohr. The model would have to be refined considerably, but characteristics of it would find vindication later. At Munich, Heisenberg also met Wolfgang Pauli, and the two brilliant scientists clicked immediately, with much in common scientifically, if not personally. The two would continue to correspond and criticize each other's work throughout their careers.
In July 1923, Heisenberg received his doctorate, but only with the lowest form of honors because he had performed miserably in the experimental portion of his physics orals. Embarrassed, he returned to Göttingen, where he had studied briefly with Max Born during Sommerfeld's absence. There, Heisenberg formulated his Zeeman principle, which earned him an invitation to Copenhagen to meet with Bohr. He would later serve as Bohr's assistant, and the latter would come to be probably the most significant intellectual influence on Heisenberg.
In 1925, while at Copenhagen, Heisenberg published his first paper laying the groundwork for his quantum mechanics. On receiving a copy of the paper, Max Born almost immediately saw that Heisenberg's multiplication of amplitudes involved a rule used in matrix multiplication–an area of mathematics to which few scientists were exposed. Months later, Born, Heisenberg, and Jordan coauthored the paper that established matrix mechanics, but their work was soon rivaled by a new approach developed by Erwin Schrödinger. Schrödinger treated the matter as waves rather than particles, and he was able to derive the same results with wave mechanics as Heisenberg had with matrix mechanics. Heisenberg acknowledged the mathematical advancement that Schrödinger's work contributed, but he refused to accept the completely different picture of the atom that the work entailed.
With Schrödinger's work gaining popularity–as physicists preferred his mathematical method–Heisenberg again captured the world's attention with his formulation of the uncertainty principle. He argued that it was impossible to determine both the exact position and velocity of a particle, as the act of seeing the particle with light necessitated a disturbance. Bohr responded with his complementarity principle, which provided an extension of Heisenberg's work, while Einstein reacted with complete disapproval of both principles, insisting on the attainability of determinism. Nevertheless, the impact of Heisenberg's work was unquestionable, and he soon became Germany's youngest full professor at Leipzig.
It was not long before the onset of the Nazi regime, as Hitler came to power in 1933. Heisenberg, throughout his career, believed in the separation of science and politics, and refused to commit either for or against the Third Reich. He made the oft-criticized choice to stay in Germany, despite the resignation and flight of many of his celebrated colleagues. He would also participate in Germany's nuclear weapons project, but he never believed the bomb would be attainable for use in the war. When Heisenberg learned that the Americans had in fact succeeded in building a bomb, he became very defensive, not only about himself, but also the state and capability of German physics in general.
After the war, Heisenberg spent much of his time on science policy rather than his own research. He would publish a few more papers but also focused on trying to ensure his place in the intellectual tradition, knowing that he had already made his most important contributions. Heisenberg passed away in his Munich home on February 1, 1976, after a battle with cancer.
