Early in his life, Schrödinger experimented in the fields of
electrical engineering,
atmospheric electricity, and atmospheric
radioactivity, but he usually worked with his former teacher Franz Exner. He also studied
vibrational theory, the theory of
Brownian motion, and
mathematical statistics. In 1912, at the request of the editors of the
Handbook of Electricity and Magnetism, he wrote an article titled
Dielectrism. That same year, he gave a theoretical estimate of the probable height distribution of radioactive substances, which is required to explain the observed radioactivity of the atmosphere, and in August 1913 executed several experiments in Zeehame that confirmed his theoretical estimate and those of
Victor Hess. For this work, he was awarded the
Haitinger Prize of the
Austrian Academy of Sciences in 1920. Other experimental studies conducted by the young researcher in 1914 were checking formulas for capillary pressure in gas bubbles and the study of the properties of soft
beta radiation produced by
gamma rays striking a metal surface. The last work he performed together with his friend Fritz Kohlrausch. In 1919, he performed his last physical experiment on
coherent light and subsequently focused on theoretical studies.
Quantum mechanics New quantum theory In the first years of his career, Schrödinger became acquainted with the ideas of the
old quantum theory, developed in the works of Einstein,
Max Planck,
Niels Bohr,
Arnold Sommerfeld, and others. This knowledge helped him work on some problems in
theoretical physics, but the Austrian scientist at the time was not yet ready to part with the traditional methods of
classical physics. Schrödinger's first publications about
atomic theory and the theory of spectra began to emerge only from the beginning of the 1920s, after his personal acquaintance with Sommerfeld and
Wolfgang Pauli and his move to Germany. In January 1921, Schrödinger finished his first article on this subject, about the framework of the
Bohr–Sommerfeld quantization of the interaction of electrons on some features of the spectra of the alkali metals. Of particular interest to him was the introduction of relativistic considerations in quantum theory. In autumn 1922, he analyzed the electron orbits in an atom from a geometric point of view, using methods developed by his friend
Hermann Weyl. This work, in which it was shown that quantum orbits are associated with certain geometric properties, was an important step in predicting some of the features of wave mechanics. Earlier in the same year, he created the Schrödinger equation of the
relativistic Doppler effect for spectral lines, based on the hypothesis of light quanta and considerations of energy and momentum. He liked the idea of his teacher Exner on the statistical nature of the conservation laws, so he enthusiastically embraced the
BKS theory of Bohr,
Hans Kramers, and
John C. Slater, which suggested the possibility of violation of these laws in individual atomic processes (for example, in the process of emission of radiation). Although the
Bothe–Geiger coincidence experiment soon cast doubt on this, the idea of energy as a statistical concept was a lifelong attraction for Schrödinger, and he discussed it in some reports and publications.
Wave mechanics In January 1926, Schrödinger published in
Annalen der Physik the paper "" (Quantization as an
Eigenvalue Problem) on wave mechanics and presented 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 a 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 most areas of quantum mechanics and indeed of all physics and chemistry. A second paper was submitted just four weeks later that solved the
quantum harmonic oscillator,
rigid rotor, and
diatomic molecule problems and gave a new derivation of the Schrödinger equation. A third paper, published in May, showed the equivalence of his approach to that of
Werner Heisenberg's
matrix mechanics and gave the treatment of the
Stark effect. A fourth paper in this series showed how to treat problems in which the system changes with time, as in scattering problems. In this paper, he introduced a complex solution to the wave equation in order to prevent the occurrence of fourth- and sixth-order differential equations. Schrödinger ultimately reduced the order of the equation to one. Building on a paper by Einstein,
Boris Podolsky, and
Nathan Rosen, which introduced the thought-experiment now known as the
EPR paradox, Schrödinger published in 1935 a paper that codified the concept of
quantum entanglement. He deemed this quantum phenomenon "the one that enforces its entire departure from
classical lines of thought." Schrödinger was not entirely comfortable with the implications of quantum theory referring to his theory as "wave mechanics". He wrote about the probability interpretation of quantum mechanics, saying, "I don't like it, and I'm sorry I ever had anything to do with it." (In order to ridicule the
viewpoints of Bohr and Heisenberg on quantum mechanics, he contrived the famous thought experiment called the
Schrödinger's cat paradox. He was said to have angrily complained to his students that "
now the damned Göttingen physicists use my beautiful wave mechanics for calculating their shitty matrix elements.")
Unified field theory Following his work on quantum mechanics, Schrödinger devoted considerable effort to working on a
unified field theory that would unite
gravity,
electromagnetism, and nuclear forces within the basic framework of
general relativity, doing the work with an extended correspondence with Albert Einstein. In 1947, he announced a result, "Affine Field Theory", in a talk at the Royal Irish Academy, but the announcement was criticized by Einstein as "preliminary" and failed to lead to the desired unified theory. This is a repetition of the first words of Schopenhauer's main work. Schopenhauer's works also introduced him to
Indian philosophy, more specifically to the
Upanishads and
Advaita Vedanta’s interpretation. He once took on a particular line of thought: "If the world is indeed created by our act of observation, there should be billions of such worlds, one for each of us. How come your world and my world are the same? If something happens in my world, does it happen in your world, too? What causes all these worlds to synchronize with each other?" There is obviously only one alternative, namely the unification of minds or consciousnesses. Their multiplicity is only apparent, in truth there is only one mind. This is the doctrine of the Upanishads.Schrödinger discussed topics such as
consciousness, the
mind–body problem,
sense perception,
free will, and
objective reality in his lectures and writings. Schrödinger's attitude with respect to the relations between Eastern and Western thought was one of prudence, expressing appreciation for Eastern philosophy while also admitting that some of the ideas did not fit with empirical approaches to natural philosophy. Some commentators have suggested that Schrödinger was so deeply immersed in a non-dualist Vedântic-like view that it may have served as a broad framework or subliminal inspiration for much of his work including that in theoretical physics. Schrödinger said that "Consciousness cannot be accounted for in physical terms. For consciousness is absolutely fundamental. It cannot be accounted for in terms of anything else." He also anticipated the
many-worlds interpretation of quantum mechanics. In 1952, he suggested that the different terms of a superposition evolving under the Schrödinger equation are "not alternatives but all really happen simultaneously". Schrödinger's later writings also contain elements resembling the
modal interpretation originated by
Bas van Fraassen. Because Schrödinger subscribed to a kind of post-
Machian neutral monism, in which "matter" and "mind" are only different aspects or arrangements of the same common elements, treating the wavefunction as physical and treating it as information became interchangeable. == Personal life ==