Niels Bohr - Biographical Profile

A photograph of Niels Bohr. Public Domain

Niels Bohr is one of the major voices in the early development of quantum mechanics. In early twentieth century, his Institute for Theoretical Physics at the University of Copenhagen, in Denmark, was a center for some of the most important revolutionary thinking in formulating and studying the discoveries and insights related to the growing information about the quantum realm. Indeed, for the majority of the twentieth century, the dominant interpretation of quantum physics was known as the Copenhagen interpretation.

Basic Information:

Fullname: Niels Henrik David Bohr

Nationality: Danish

Birth: Oct. 7, 1885
Death: Nov. 18, 1962

Spouse: Margrethe Norlund

1922 Nobel Prize for Physics: "for his services in the investigation of the structure of atoms and of the radiation emanating from them."

Early Years:

Bohr was born in Copenhagen, Denmark. He received a doctorate from Copenhagen University in 1911.

In 1913, he developed the Bohr model of atomic structure, which introduced the theory of electrons orbiting around the atomic nucleus. His model involved the electrons being contained in quantized energy states so that when they drop from one state to another, energy is emitted. This work became central to quantum physics and it for this which he was awarded the 1922 Nobel Prize.

Copenhagen:

In 1916, Bohr became a professor at Copenhagen University. In 1920, he was appointed director of the new Institute of Theoretical Physics, later renamed the Niels Bohr Institute.

In this position, he was in a position to be instrumental in building the theoretical framework of quantum physics. The standard model of quantum physics throughout the first half of the century became known as the "Copenhagen interpretation," although several other interpretations now exist. Bohr's careful, thoughtful manner of approaching was colored with a playful personality, as clear in some famous Niels Bohr quotes.

Bohr & Einstein Debates:

Albert Einstein was a known critic of quantum physics, and he frequently challenged Bohr's views on the subject. Through their prolonged and spirited debate, the two great thinkers helped refine a century-long understanding of quantum physics.

One of the most famous outcomes of this discussion was Einstein's famous quote that "God does not play dice with the universe," to which Bohr is said to have replied, "Einstein, stop telling God what to do!" (The debate was cordial, if spirited. In a 1920 letter, Einstein said to Bohr, "Not often in life has a human being caused me such joy by his mere presence as you did.")

On a more productive note, the physics world pays more attention to the outcome of these debates that led to valid research questions: an attempted counter-example that Einstein proposed known as the EPR paradox. The goal of the paradox was to suggest that the quantum indeterminancy of quantum mechanics led to an inherent non-locality. This was quantified years later in Bell's theorem, which is an experimentally-accessible formulation of the paradox. Experimental tests have confirmed the non-locality that Einstein created the thought experiment to refute.

Bohr & World War II:

One of Bohr's students was Werner Heisenberg, who became the leader of the German atomic research project during World War II. During a somewhat famous private meeting, Heisenberg visited with Bohr in Copenhagen in 1941, the details of which have been a matter of scholarly debate since neither ever spoke freely of the meeting, and the few references have conflicts.

Bohr escaped arrest by German police in 1943, eventually making it to the United States where he worked at Los Alamos on the Manhattan Project, though implications are that his role was primarily that of a consultant.

Nuclear Energy & Final Years:

Bohr returned to Copenhagen after the war and spent the rest of his life advocating the peaceful use of nuclear energy.