Erwin Rudolf Josef Alexander Schrödinger (12 August 1887 – 4 January 1961) was an Austrian physicist who achieved fame for his contributions to quantum mechanics, especially the Schrödinger equation, for which he received the Nobel Prize in 1933. In 1935, after extensive correspondence with personal friend Albert Einstein, he proposed the Schrödinger's cat thought experiment.
In 1921, he moved to the University of Zürich. In January 1926, Schrödinger published in the Annalen der Physik the paper "Quantisierung als Eigenwertproblem" [tr. Quantisation as an Eigenvalue Problem] on wave mechanics and what is now known as the Schrödinger equation. In this paper he gave a "derivation" of the wave equation for time independent systems, and showed that it gave the correct energy eigenvalues for the hydrogen-like atom. This paper has been universally celebrated as one of the most important achievements of the twentieth century, and created a revolution in quantum mechanics, and indeed of all physics and chemistry. A second paper was submitted just four weeks later that solved the quantum harmonic oscillator, the rigid rotor and the diatomic molecule, and gives a new derivation of the Schrödinger equation. A third paper in May showed the equivalence of his approach to that of Heisenberg and gave the treatment of the Stark effect. A fourth paper in this most remarkable series showed how to treat problems in which the system changes with time, as in scattering problems. These papers were the central achievement of his career and were at once recognized as having great significance by the physics community.
In 1927, he succeeded Max Planck at the Friedrich Wilhelm University in Berlin. In 1933, however, Schrödinger decided to leave Germany; he disliked the Nazis' anti-semitism. He became a Fellow of Magdalen College at the University of Oxford. Soon after he arrived, he received the Nobel Prize together with Paul Adrien Maurice Dirac. His position at Oxford did not work out; his unconventional personal life (Schrödinger lived with two women) was not met with acceptance. In 1934, Schrödinger lectured at Princeton University; he was offered a permanent position there, but did not accept it. Again, his wish to set up house with his wife and his mistress may have posed a problem. He had the prospect of a position at the University of Edinburgh but visa delays occurred, and in the end he took up a position at the University of Graz in Austria in 1936.
In 1940 he received an invitation to help establish an Institute for Advanced Studies in Dublin, Ireland. He became the Director of the School for Theoretical Physics and remained there for 17 years, during which time he became a naturalized Irish citizen. He wrote about 50 further publications on various topics, including his explorations of unified field theory.
In 1944, he wrote What is Life?, which contains a discussion of Negentropy and the concept of a complex molecule with the genetic code for living organisms. According to James D. Watson's memoir, DNA, The Secret of Life, Schrödinger's book gave Watson the inspiration to research the gene, which led to the discovery of the DNA double helix structure. Similarly, Francis Crick, in his autobiographical book What Mad Pursuit, described how he was influenced by Schrödinger's speculations about how genetic information might be stored in molecules. Schrödinger stayed in Dublin until retiring in 1955. During this time he remained committed to his particular passion; scandalous involvements with students occurred and he fathered two children by two different Irish women. He had a life-long interest in the Vedanta philosophy of Hinduism, which influenced his speculations at the close of What is Life? about the possibility that individual consciousness is only a manifestation of a unitary consciousness pervading the universe.
In 1956, he returned to Vienna (chair ad personam). At an important lecture during the World Energy Conference he refused to speak on nuclear energy because of his skepticism about it and gave a philosophical lecture instead. During this period Schrödinger turned from mainstream quantum mechanics' definition of wave-particle duality and promoted the wave idea alone causing much controversy.
The request for March stemmed from Schrödinger's unconventional relationships with women. Whilst his relations with his wife were good he had had many lovers with his wife's knowledge. Anny had her own lover for many years, Schrödinger's friend Hermann Weyl. Schrödinger asked for March to be his assistant because, at that time, he was in love with March's wife Hilde.
Many of the scientists who had left Germany spent the summer of 1933 in the Italian province of Bolzano. Here Hilde became pregnant with Schrödinger's child. On 4 November 1933 Schrödinger, his wife and Hilde March arrived in Oxford. Schrödinger had been elected a fellow of Magdalen College. Soon after they arrived in Oxford, Schrödinger heard that, for his work on wave mechanics, he had been awarded the Nobel prize.
In early 1934 Schrödinger was invited to lecture at Princeton University and while there he was made an offer of a permanent position. On his return to Oxford he negotiated about salary and pension conditions at Princeton but in the end he did not accept. It is thought that the fact that he wished to live at Princeton with Anny and Hilde both sharing the upbringing of his child was not found acceptable. The fact that Schrödinger openly had two wives, even if one of them was married to another man, was not well received in Oxford either. Nevertheless, his daughter Ruth Georgie Erica was born there on 30 May 1934.
On 4 January 1961, Schrödinger died in Vienna of tuberculosis at the age of 73. He left a widow, Anny (born Annemarie Bertel on 3 December 1896, died 3 October 1965), and was buried in Alpbach (Austria).
The philosophical issues raised by Schrödinger's cat are still debated today and remains his most enduring legacy in popular science (Schrödinger's equation being his most enduring legacy at a more technical level). The huge Schrödinger crater on the far side of the Moon was posthumously named after him by the IAU. The Erwin Schrödinger International Institute for Mathematical Physics was established in Vienna in 1993.
The second of these is available in English as "Outline of a Theory of Color Measurement for Daylight Vision" in Sources of Color Science, Ed. David L. MacAdam, The MIT Press (1970), 134-182.