- Person
- Max Born
- Lived
- 1882–1970
- Field
- Quantum mechanics
- From
- German-British
The story
By the early 1920s the original quantum theory of the atom, which pictured electrons as particles moving in orbits, was proving inadequate. At Göttingen, Max Born and his young assistants were searching for a new mechanics for the atom. On 9 July 1925 Werner Heisenberg, then Born's assistant, handed his professor a paper to review and submit for publication. In it Heisenberg abandoned unobservable electron orbits and worked instead with quantities such as the probabilities of quantum jumps, arranged in arrays with two indices for the starting and final states. Heisenberg did not know what kind of mathematics he was using.
Born did. He recognised the arrays as matrices, which he had learned as a student in Breslau and had used in his work on crystal lattices in 1921. At the time matrices were seldom used by physicists and were thought to belong to pure mathematics. With his assistant and former student Pascual Jordan, Born began at once to transcribe and extend Heisenberg's idea, and their paper was received for publication just 60 days after Heisenberg's. A follow-up paper by all three was submitted before the end of the year. Together they set out matrix mechanics, the first complete form of quantum mechanics.
Its central law was entirely Born's: the canonical commutation relation between position and momentum, pq − qp = h/2πi, whose left side is not zero because the order in which matrices are multiplied matters. Born considered that his paper with Jordan contained the most important principles of quantum mechanics, and it put Heisenberg's approach on a solid mathematical basis. Soon afterwards Wolfgang Pauli used the method to calculate the energy levels of hydrogen and found that they agreed with Bohr's model of the atom.
The relation became one of the foundations of quantum theory and leads directly to Heisenberg's uncertainty principle. Heisenberg alone received the 1932 Nobel Prize for creating quantum mechanics, and he wrote to Born of his bad conscience at being honoured alone for work done together in Göttingen. Born's own prize came in 1954.
Born was proud of the relation to the end. When he died in 1970 he was buried in the Stadtfriedhof in Göttingen, near Max Planck, Otto Hahn and David Hilbert, and his gravestone is inscribed with the equation.
Why it matters
Matrix mechanics and its commutation rule remain a foundation of quantum physics and its technologies.
About Max Born
Physicist who co-founded quantum mechanics and gave the wave function its probability meaning; dismissed from Göttingen by the Nazis in 1933, he won the Nobel Prize in exile in 1954.
More about Max Born
- Max Born founded the physics of vibrating crystalsIn 1912 Max Born and Theodore von Kármán founded lattice dynamics, explaining how atomic vibrations set a solid's properties; Born later wrote the classic text on it.
- Max Born built a home for refugee scientists in EdinburghDriven out of Germany in 1933, Max Born became Tait Professor at Edinburgh in 1936 and built a research group made up mostly of refugees from Europe.
- Max Born trained a generation of great physicistsAt Göttingen in the 1920s Max Born supervised Oppenheimer, Maria Goeppert Mayer, Max Delbrück and others, while Pauli, Heisenberg, Fermi and Wigner served as his assistants.
- The Born–Haber cycle is still taught to chemistsA chance meeting between Max Born and Fritz Haber around 1918 produced the Born–Haber cycle, a method chemistry students still use to analyse ionic compounds.
- Max Born showed quantum waves give probabilitiesIn 1926 Max Born proposed that the quantum wave function gives the probability of finding a particle, the Born rule, winning a share of the 1954 Nobel Prize.
- Max Born co-wrote the classic book on opticsMax Born and Emil Wolf wrote Principles of Optics, published in 1959, which became a standard reference on the physics of light for generations of scientists.
- Max Born rallied Nobel laureates against nuclear warIn 1955 Max Born and Otto Hahn initiated the Mainau Declaration, in which Nobel laureates warned against nuclear weapons; within a year 52 laureates had signed.
Sources
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.