- Person
- Max Born
- Lived
- 1882–1970
- Field
- Quantum mechanics
- From
- German-British
The story
By 1926 physics had two new theories of the atom. At Göttingen, Max Born, Werner Heisenberg and Pascual Jordan had built matrix mechanics. Then Erwin Schrödinger introduced wave mechanics, describing electrons with a mathematical wave that obeyed his new equation. Many physicists found Schrödinger's version appealing because it seemed to promise a return to the continuous, deterministic world of classical physics. But what was the wave? Schrödinger suggested it might describe a smeared-out electron, an idea that did not fit the experimental facts.
Max Born, director of theoretical physics at Göttingen and born to a Jewish family in Breslau, offered a different answer in a paper on collision processes published in July 1926. The wave function, he proposed, does not describe where the particle is, but how likely it is to be found in each place: the probability is given by the square of the wave's magnitude. More generally, the rule gives the probability that any measurement on a quantum system will yield a particular result. This became known as the Born rule.
The idea broke with strict determinism. Albert Einstein, Born's close friend since their years together in Berlin, never accepted it. In a letter to Born in December 1926 he wrote that quantum mechanics was certainly imposing, but that an inner voice told him it was not yet the real thing, and that he was convinced God was not playing at dice. The two friends debated the question in letters for decades, a correspondence later published as The Born–Einstein Letters.
Born's interpretation nonetheless became the standard way physicists use quantum theory. His fellow physicists kept nominating him for the Nobel Prize, and in 1954 he shared the Nobel Prize in Physics with Walther Bothe, for his fundamental research in quantum mechanics, especially his statistical interpretation of the wave function, work he had done alone. In his Nobel lecture he called the loosening of thinking brought by such ideas the greatest blessing modern science had given.
Every prediction quantum physics makes about real experiments passes through the Born rule. It connects the abstract mathematics of the theory to what is actually observed, and it underlies the design of technologies from lasers and transistors to the qubits of quantum computers.
Why it matters
The Born rule connects quantum theory to every measurement, underpinning lasers, transistors, MRI and quantum computing.
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 found quantum mechanics' central equationIn 1925 Max Born recognised Heisenberg's new physics as matrix algebra and found its key law, the commutation relation now carved on his gravestone.
- 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
- Max Born Wikipedia
- Max Born MacTutor History of Mathematics, University of St Andrews
- Born rule Wikipedia
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.