Max Born (German: [ˈmaks ˈbɔʁn] ; 11 December 1882 – 5 January 1970) was a German–British theoretical physicist who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics, and supervised the work of a number of notable physicists in the 1920s and 1930s. He shared the 1954 Nobel Prize in Physics with Walther Bothe "for his fundamental research in quantum mechanics, especially for his statistical interpretation of the wavefunction."
Born entered the University of Göttingen in 1904, where he met the three renowned mathematicians Felix Klein, David Hilbert, and Hermann Minkowski. He wrote his Ph.D. thesis on the subject of the stability of elastic wires and tapes, winning the university's Philosophy Faculty Prize. In 1905, he began researching special relativity with Minkowski, and subsequently wrote his habilitation thesis on the Thomson model of the atom. A chance meeting with Fritz Haber in Berlin in 1918 led to discussion of how an ionic compound is formed when a metal reacts with a halogen, which is now known as the Born–Haber cycle.
During World War I, Born was originally placed as a radio operator, but his specialist knowledge led to his being moved to research duties on sound ranging. In 1921 Born returned to Göttingen, where he arranged another chair for his long-time friend and colleague James Franck. Under Born, Göttingen became one of the world's foremost centres for physics. In 1925, Born and Werner Heisenberg formulated the matrix mechanics representation of quantum mechanics. The following year, he formulated the now-standard interpretation of the probability density function for ψ*ψ in the Schrödinger equation, for which he was awarded the Nobel Prize in 1954.
His influence extended far beyond his own research: Max Delbrück, Siegfried Flügge, Friedrich Hund, Pascual Jordan, Maria Goeppert Mayer, Lothar Nordheim, Robert Oppenheimer, and Victor Weisskopf all received their Ph.D. degrees under Born at Göttingen, and his assistants included Enrico Fermi, Werner Heisenberg, Gerhard Herzberg, Friedrich Hund, Wolfgang Pauli, Léon Rosenfeld, Edward Teller, and Eugene Wigner.
In January 1933, when the Nazi Party came to power in Germany, Born, who was born into a Jewish family, was suspended from his professorship at the University of Göttingen. He emigrated to the United Kingdom, where he took a job at St John's College, Cambridge, and wrote a popular science book, The Restless Universe, as well as Atomic Physics, which soon became a standard textbook. In October 1936, he was appointed Tait Professor of Natural Philosophy at the University of Edinburgh, where, working with German-born assistants Ernst Walter Kellermann and Klaus Fuchs, he continued his research into physics. He became a naturalised British subject on 31 August 1939, one day before the German invasion of Poland that started World War II in Europe. He remained in Edinburgh until 1952, when he retired to Bad Pyrmont, West Germany, and died in a hospital in Göttingen on 5 January 1970.
Max Born was born on 11 December 1882 in Breslau (now Wrocław, Poland), Germany, into a family of Jewish descent. He was one of two children of anatomist and embryologist Gustav Jacob Born, who was Professor of Embryology at the University of Breslau, and Margarethe Gretchen Kauffmann, who came from a Silesian family of industrialists. Margarethe died on 29 August 1886, when Max was age four. He had a sister, Käthe, who was born in 1884, and a half-brother—Wolfgang—from his father's second wife, Bertha Lipstein. Wolfgang later became Professor of Art History at the City College of New York.
Initially educated at the König-Wilhelm-Gymnasium in Breslau, Born entered the University of Breslau in 1901. The German university system allowed students to move easily from one university to another, so he spent summer semesters at Heidelberg University in 1902 and the University of Zurich in 1903. Fellow students at the University of Breslau, Otto Toeplitz and Ernst Hellinger, told him about the University of Göttingen, and he went there in April 1904. At Göttingen he found three renowned mathematicians: Felix Klein, David Hilbert, and Hermann Minkowski. Very soon after his arrival, he formed close ties to the latter two men. From the first class he took with Hilbert, Hilbert identified him as having exceptional abilities and selected him as the lecture scribe, whose function was to write up the class notes for the students' mathematics reading room at the University of Göttingen. Being class scribe put him into regular, invaluable contact with Hilbert. Hilbert became his mentor after selecting him to be the first to hold the unpaid, semi-official position of assistant. Born's introduction to Minkowski came through his stepmother, Bertha, as she knew Minkowski from dancing classes in Königsberg. The introduction netted him invitations to the Minkowski household for Sunday dinners. In addition, while performing his duties as scribe and assistant, he often saw Minkowski at Hilbert's house.
Born's relationship with Felix Klein was more problematic. He attended a seminar conducted by Klein, Carl Runge, and Ludwig Prandtl on the subject of elasticity. Although not particularly interested in the subject, he was obliged to present a paper. He presented one in which, taking the simple case of a curved wire with both ends fixed, he used Hilbert's calculus of variations to determine the configuration that would minimise potential energy and therefore be the most stable. Klein was impressed, and invited him to submit a thesis on the subject of "Stability of Elastica in a Plane and Space" – a subject near and dear to Klein – which Klein had arranged to be the subject for the prestigious annual Philosophy Faculty Prize offered by the university. Entries could also qualify as doctoral dissertations. He responded by turning down the offer, as applied mathematics was not his preferred area of study. Klein was greatly offended.
Felix Klein had the power to make or break academic careers, so Born felt compelled to atone by submitting an entry for the prize. Because Klein refused to supervise him, Born arranged for Carl Runge to be his thesis advisor. Woldemar Voigt and Karl Schwarzschild became his other examiners. Starting from his paper, he developed the equations for the stability conditions. As he became more interested in the topic, he had an apparatus constructed that could test his predictions experimentally. On 13 June 1906, the rector announced that he had won the prize. A month later, he passed his oral examination and was awarded his Ph.D. in Mathematics with magna cum laude distinction.
On graduation, Born was obliged to perform his military service, which he had deferred while a student. He found himself drafted into the German Army, and posted to the 2nd Guards Dragoons "Empress Alexandra of Russia", which was stationed in Berlin. His service was brief, as he was discharged early after an asthma attack in January 1907. He then travelled to England, where he was admitted to Gonville and Caius College, Cambridge, and studied physics for six months in the Cavendish Laboratory, under J. J. Thomson, George Searle, and Joseph Larmor. After he returned to Germany, the army reinducted him, and he served with the elite 1st (Silesian) Life Cuirassiers "Great Elector" until he was again medically discharged after just six weeks' service. He then returned to Breslau, where he worked under the supervision of Otto Lummer and Ernst Pringsheim, hoping to do his habilitation in physics. A minor accident involving Born's black body experiment, a ruptured cooling water hose, and a flooded laboratory, led to Lummer telling him that he would never become a physicist.
In 1905, Albert Einstein published his paper On the Electrodynamics of Moving Bodies about special relativity. He was intrigued, and began researching the subject. He was devastated to discover that Hermann Minkowski was also researching special relativity along the same lines, but when he wrote to Minkowski about his results, Minkowski asked him to return to Göttingen and do his habilitation there. Born accepted. Toeplitz helped him brush up on his matrix algebra so he could work with the four-dimensional Minkowski space matrices used in the latter's project to reconcile relativity with electrodynamics. Born and Minkowski got along well, and their work made good progress, but Minkowski died suddenly of appendicitis on 12 January 1909. The mathematics students had him speak on their behalf at the funeral.