# Schrödinger, Erwin

### wave particle mechanics physics

[ **shroe** dinger] (1887–1961) Austrian physicist: the founder of wave mechanics.

Schrödinger was the son of a prosperous oilcloth manufacturer; he was educated by a private tutor and by his father before going to the University of Vienna. After his doctorate in physics in 1910 he joined the staff there. During the First World War he served as an artillery officer in an isolated fort, which gave him time to read physics; from 1920 he spent short periods of time as a student at Jena, Stuttgart, Breslau and Zürich. He began to produce inspired work, and early in 1926 published a series of papers founding wave mechanics. As a result he succeeded as professor of theoretical physics at Berlin (1927), but chose to leave once Hitler had assumed power in 1933. He moved to Oxford, but became homesick and returned to Graz in Austria in 1936. When the Germans moved into Austria in 1938 Schrödinger fled for his life, settling in Dublin and working at the Institute for Advanced Studies created for him there, as a result of the Irish Taoiseach (prime minister) de Valera’s mathematical interests. After 17 happy years in Eire, he became a professor at the University of Vienna, having refused to return until Soviet occupation ceased. Shortly after arriving he became ill and never fully recovered.

Schrödinger began to think about the consequences of ideas when they were published in 1924. The latter had postulated that any particle has a wave associated with it and the properties of the particle result from a combination of its particle-like and wave-like nature. Schrödinger and Broglie both realized that a partial differential equation called a wave equation would describe the motion of a particle, and deduced an equation of this type. This approach of considering the wave function alone avoided the difficulties which old quantum theory of particles had involved, but was difficult to apply in practice. Schrödinger then used method for describing particle motion, and wrote this in wave form to give ‘Schrödinger’s equation’. Unlike the previous equation this ignores relativistic effects, but is much easier to visualize (as standing waves around the nucleus) and to apply to real situations. When applied to the hydrogen atom the equation gives the correct energy levels of an electron in the atom, without the *ad hoc* assumptions of Bohr’s model of the atom. These energy levels had been measured experimentally by using the lines observed in the hydrogen spectrum. For this considerable achievement he shared the 1933 Nobel Prize for physics with .

Schrödinger’s theory was known as wave mechanics (1926), and was shown by Dirac to be mathematically equivalent to matrix mechanics, devised in 1925 by . The combined theory, together with exclusion principle, was used by Dirac to set out quantum mechanics in virtually complete form by the year’s end.

While quantum mechanics had great predictive power and correctly described a wealth of previously unexplained phenomena, Schrödinger saw in it an awkward problem. Relating the wave function to the particle (for example an electron) is difficult. Born put forward the now-accepted explanation that the wave amplitude describes the probability of finding the particle at that point. Schrödinger, like Broglie and , opposed this, and together they argued against a probabilistic quantum mechanics. Born’s view condemns physics to describing only the likelihood of one event following another and is not able to definitely predict cause and effect, as classical theories sought to do.

Schrödinger had an informal manner much liked by his colleagues and students; throughout his life he travelled with walking-boots and rucksack, which caused him some problems in gaining entrance to the Solvay conferences for Nobel laureates.

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