Erwin Schrödinger · aiwiki.page

Erwin Schrödinger (12 August 1887 – 4 January 1961) was an Austrian theoretical physicist and a principal founder of quantum mechanics. In 1926 he developed wave mechanics, expressing atomic behavior through the Schrödinger equation. His formulation provided a powerful means of calculating atomic energy levels and helped establish the mathematical framework of modern physics. He shared the 1933 Nobel Prize in Physics with Paul Dirac for their contributions to atomic theory. (geschichte.univie.ac.at)

Schrödinger also examined what quantum theory implies about physical reality. His 1935 writings introduced the term entanglement and the cat thought experiment, which exposed the difficulty of relating quantum superpositions to definite macroscopic outcomes. Beyond physics, his book What Is Life? (1944) examined heredity and biological order in physical terms and influenced researchers entering molecular biology. His career extended across continental Europe, Oxford, and Dublin before his return to Vienna in 1956; his later writings addressed scientific knowledge, consciousness, and the relationship between mind and matter. (personal.lse.ac.uk)

Family background, education, and early career

Erwin Schrödinger was born in Vienna on 12 August 1887, the only child of Rudolf Schrödinger and Georgine Bauer. Rudolf had studied chemistry under Georgine’s father, Alexander Bauer, at Vienna’s Technical College. He managed the family’s oilcloth business while pursuing interests in Italian painting and botany, eventually publishing research on plant phylogeny. Scientific inquiry and literary culture were therefore familiar features of Schrödinger’s upbringing rather than interests encountered only at university. His own school-age enthusiasms included scientific subjects, the grammatical structure of ancient languages, and German poetry. (nobelprize.org)

Educated initially by private tutors, Schrödinger entered Vienna’s Akademisches Gymnasium in September 1898 and completed his schooling on 11 July 1906 with distinction. His education followed the classical Gymnasium route to university in late Habsburg Austria-Hungary, combining sustained language study with mathematics and science. This humanistic training preceded, rather than competed with, his professional specialization in physics. He enrolled at the University of Vienna in autumn 1906 and studied there until 1910, receiving mathematical instruction from Wilhelm Wirtinger, experimental training from Franz Serafin Exner, and theoretical instruction from Friedrich, usually called Fritz, Hasenöhrl. (zbphysik.univie.ac.at)

Hasenöhrl was particularly influential in introducing Schrödinger to the theoretical tradition of Ludwig Boltzmann, including the treatment of matter through statistical mechanics and thermodynamics. Schrödinger was not Boltzmann’s direct pupil: Boltzmann died in 1906, before Schrödinger began his university studies, and Hasenöhrl succeeded him that September. Exner provided a complementary experimental environment. Schrödinger’s doctoral dissertation, completed in 1910, investigated the conduction of electricity along insulating surfaces in moist air—an experimental problem concerning the electrical behavior of materials, not an early formulation of quantum wave mechanics. He received his doctorate on 20 May 1910. (zbphysik.univie.ac.at)

After a year of military service in 1910–1911, Schrödinger became Exner’s assistant at Vienna’s Second Physical Institute in 1911. His early publications ranged across dielectric behavior, magnetism, atmospheric radiation, and the dynamics of vibrating systems. In January 1914 he obtained his habilitation, qualifying him to lecture as a Privatdozent; the associated research concerned dielectrics, melting, pyroelectricity, and piezoelectricity. The outbreak of the First World War interrupted this developing academic career. From 1914 to 1918 he served as an officer in the Austro-Hungarian fortress artillery, including service on the Italian front and a later assignment to meteorological work in Vienna. (schroedinger100.univie.ac.at)

On 24 March 1920 Schrödinger married Annemarie Bertel. With no suitable permanent position available in Vienna, he moved through several appointments in rapid succession: an assistantship under Max Wien at Jena in 1920, followed by an associate professorship there; an associate professorship at Stuttgart’s Technische Hochschule for the winter semester of 1920–1921; and a full professorship in theoretical physics at Breslau for the summer semester of 1921. In October 1921 he took up the chair of theoretical physics at the University of Zürich, ending this period of short appointments. (zbphysik.univie.ac.at)

The creation of wave mechanics

Atomic spectroscopy posed a central problem for early quantum theory: atoms emitted and absorbed sharply defined frequencies, but classical electron orbits did not explain their discrete energies. The Bohr–Sommerfeld theory selected particular orbits through imposed quantum conditions rather than deriving quantization from a general dynamical law. Louis de Broglie’s 1924 proposal associated matter with waves of wavelength $\lambda=h/p$ , where $h$ is the Planck constant and $p$ the momentum. This suggested a different explanation: allowed atomic states might resemble the standing-wave modes of a vibrating system. Schrödinger developed that possibility into a theory in which discrete energies emerged from a wave problem rather than from separately prescribed orbital rules. (nobelprize.org)

The mathematical bridge was William Rowan Hamilton’s analogy between classical mechanics and optics. Geometrical optics describes rays, whereas wave optics explains interference and diffraction; similarly, Schrödinger proposed treating particle trajectories as an approximation to a more fundamental wave mechanics. The Hamilton–Jacobi formulation supplied the connection between mechanical action and wave phase. Extending the analogy beyond rays led him to seek a differential equation whose admissible solutions would determine atomic energies. His December 1926 exposition, “An Undulatory Theory of the Mechanics of Atoms and Molecules,” explicitly organized the argument around this transition from geometrical to physical optics. (doi.org)

The first of four papers entitled Quantisierung als Eigenwertproblem (“Quantization as an Eigenvalue Problem”) reached Annalen der Physik on 27 January 1926. It treated the nonrelativistic, unperturbed hydrogen atom, replacing the old quantum conditions with a variational problem and restrictions on acceptable wave solutions. The permitted energies appeared as eigenvalues, reproducing the hydrogen energy spectrum without assigning the electron a definite orbit. The second communication developed the mechanics–optics analogy more systematically and extended the method to the harmonic oscillator and rotator. Published in volume 79, pages 361–376 and 489–527, these papers established wave mechanics initially through stationary-state problems. (schroedinger100.univie.ac.at)

The third communication, published in volume 80, pages 437–490, developed perturbation theory and applied it to the Stark effect—the splitting of hydrogen’s Balmer lines by an electric field. This made the theory applicable when an exactly solvable system was modified by an additional interaction. The fourth, in volume 81, pages 109–139, moved beyond stationary eigenvalue calculations to time-dependent wave mechanics. It introduced the general evolution equation now called the Schrödinger equation and treated time-dependent disturbances, providing a framework for discussing transitions and radiation rather than only lists of allowed energies. (zbphysik.univie.ac.at)

Between the second and third communications, Schrödinger published “On the Relation between the Quantum Mechanics of Heisenberg, Born, and Jordan, and My Own.” Werner Heisenberg, Max Born, and Pascual Jordan had developed matrix mechanics using arrays of quantities associated with pairs of states, apparently far removed from continuous wave equations. Schrödinger showed how matrices could be constructed from wave-mechanical eigenfunctions: integrals involving pairs of eigenfunctions and an observable supplied the corresponding matrix elements. His argument established a mathematical connection between the formulations, not an agreement about what their symbols represented physically. He continued to seek a continuous wave description; his December exposition interpreted the wave function in terms of a continuous distribution of electric charge. That interpretive proposal was distinct from the equivalence of the calculational methods. (mwolf.pracownicy.uksw.edu.pl)

The Schrödinger equation and its physical content

The time-dependent Schrödinger equation specifies how a quantum state evolves:

i\hbar\frac{\partial\psi}{\partial t}=\hat H\psi.

Here $i$ is the imaginary unit, $\hbar=h/(2\pi)$ is the reduced Planck constant, and $\psi$ is the generally complex wave function. The Hamiltonian operator $\hat H$ represents the system’s energy and determines its dynamics. For a single particle of mass $m$ in a prescribed potential energy $V(\mathbf r,t)$ , with no magnetic field or spin-dependent interaction,

\hat H=-\frac{\hbar^2}{2m}\nabla^2+V(\mathbf r,t).

The spatial derivatives encode kinetic energy; multiplication by $V$ encodes potential energy. Given an initial wave function and appropriate conditions on its domain, the equation determines its subsequent evolution. Schrödinger published his wave-mechanical formulation in 1926, including four papers entitled Quantisierung als Eigenwertproblem (“Quantization as an Eigenvalue Problem”). (ocw.mit.edu)

The wave function is not itself a directly measured displacement like that of a vibrating string. Under the Born rule, $|\psi(\mathbf r,t)|^2\,d^3r$ gives the probability of finding the particle in a small volume $d^3r$ around $\mathbf r$ . A normalized one-particle state therefore satisfies $\int|\psi|^2\,d^3r=1$ . Evolution under a self-adjoint Hamiltonian preserves this normalization. The equation is also linear: if two wave functions solve it for the same Hamiltonian, any constant-coefficient linear combination is another solution. This property underlies quantum superposition and interference; the probability density of a sum generally contains interference terms and is not simply the sum of the separate probability densities. (ocw.mit.edu)

When the Hamiltonian is independent of time, states of definite energy can be written as $\psi(\mathbf r,t)=\phi(\mathbf r)e^{-iEt/\hbar}$ , where

\hat H\phi=E\phi.

This is an eigenvalue equation: the admissible functions $\phi$ are energy eigenfunctions, and their eigenvalues $E$ are possible measured energies. Such states are called stationary because their position probability density remains constant, although their complex phase changes with time. “Stationary” does not mean that an electron follows a motionless classical trajectory. Superpositions of different energies acquire different phase factors, allowing their spatial probability distributions to change with time. (ocw.mit.edu)

For hydrogen, separating the motion of the atom’s centre of mass leaves an electron–proton relative coordinate with Coulomb potential $V(r)=-e^2/(4\pi\varepsilon_0r)$ . The kinetic term then uses the reduced mass $\mu=m_em_p/(m_e+m_p)$ . Requiring bound-state solutions to be single-valued, regular at the origin, and square-integrable selects discrete negative energies:

E_n=-\frac{\mu e^4}{2(4\pi\varepsilon_0)^2\hbar^2n^2} \approx-\frac{13.6\ \mathrm{eV}}{n^2}, \qquad n=1,2,3,\ldots.

Thus energy quantization follows from the differential equation together with admissibility conditions, rather than from separately imposed permitted orbits. The ground-state and $n=2$ energies are approximately $-13.6$ and $-3.4$ electronvolts. The associated atomic orbitals have spatial forms labelled by the quantum numbers $n,l,m$ . Hydrogen also has positive-energy scattering states: its spectrum is not entirely discrete. (arxiv.org)

The original scalar equation uses nonrelativistic kinetic energy and does not incorporate special relativity. It describes hydrogen’s principal energy levels but does not by itself supply the electron’s spin, an intrinsic angular momentum distinct from orbital motion. A single scalar amplitude has no independent components representing the electron’s two spin states; a nonrelativistic spin description requires an enlarged state and appropriate interactions. Paul Dirac’s relativistic equation, introduced in 1928, instead uses a multicomponent wave function and incorporates spin- $\tfrac12$ structure. The general equation $i\hbar\,\partial\psi/\partial t=\hat H\psi$ can nevertheless describe spin when $\psi$ and $\hat H$ act on the enlarged state space: the limitation concerns the original scalar Hamiltonian, not every use of Schrödinger-form time evolution. (ocw.mit.edu)

Berlin, Oxford, and displacement from Austria

On 1 October 1927, Schrödinger succeeded Max Planck as professor of theoretical physics at the University of Berlin, leaving Zürich after the publication of his principal wave-mechanical papers. He was elected to the Prussian Academy of Sciences in 1929. His Berlin appointment ended in 1933, following the National Socialists’ accession to power and the dismissal of Jewish academics. Schrödinger was not himself subject to dismissal on racial grounds: his departure was voluntary, in opposition to the regime’s policies. Frederick Lindemann, head of Oxford’s Clarendon Laboratory, helped arrange an alternative position through a programme supported by Imperial Chemical Industries (ICI), which financed posts for scientists leaving Germany. (api.pageplace.de)

Schrödinger was elected a fellow of Magdalen College on 3 October 1933 and moved to the University of Oxford that autumn. His support combined a college fellowship with funding supplied principally by ICI, rather than a conventional university chair. In November, shortly after his arrival, the Nobel Prize in Physics for 1933 was announced jointly for Schrödinger and Paul Dirac, “for the discovery of new productive forms of atomic theory”; each received half the prize. The award therefore belonged to his Oxford period, although the work underlying his wave mechanics had been completed in Zürich before his move to Berlin. His Oxford residence continued until 1936. (api.pageplace.de)

On 1 October 1936, Schrödinger took up a professorship at the University of Graz in Austria. He also became an honorary professor at the University of Vienna, where he lectured on theoretical physics. Austria’s annexation by Nazi Germany in March 1938 placed both appointments under National Socialist authority. On 31 March, the Graz newspaper Tagespost published a declaration in which Schrödinger endorsed the annexation and urged support in the forthcoming plebiscite. Whatever protection this declaration might have afforded, it did not preserve his positions: the education ministry revoked his Vienna honorary professorship on 22 April, and the Reich governor’s administration ordered his dismissal from Graz at the end of August, effective on 1 September. (api.pageplace.de)

Schrödinger left Austria in September 1938. His route took him through Rome, Geneva, and Zürich before a temporary return to Oxford, where friends accommodated him. In December he moved to Belgium as a visiting professor at the University of Ghent, supported through the Fondation Francqui. This was an interim appointment while plans for a research institute in Ireland were still being developed; his departure from Austria did not lead directly to an established Dublin post. (superphysics.org)

At the invitation of the Irish head of government, Éamon de Valera, Schrödinger moved to Dublin in October 1939. De Valera intended his appointment to help establish an internationally recognised centre for theoretical research, alongside a school of Celtic studies. Schrödinger’s arrival preceded the formal establishment of the Dublin Institute for Advanced Studies in 1940. He became its senior professor of theoretical physics that year; before its premises were ready, he delivered quantum-theory courses at the Royal Irish Academy. The School of Theoretical Physics initially consisted of Schrödinger alone, and he moved into its accommodation at 65 Merrion Square in February 1941. (dib.ie)

Quantum interpretation, entanglement, and the cat

Schrödinger preferred a description of atomic processes in terms of continuously evolving waves rather than particles undergoing discontinuous quantum jumps. He resisted treating the wave function solely as an instrument for predicting measurement probabilities, seeking a physical account of what occurred between observations. These interpretive commitments were distinct from the predictive success of wave mechanics: disagreement concerned what its mathematics represented, not simply whether its calculations matched atomic phenomena. His continued opposition to discontinuous transitions appeared explicitly in his 1952 essay “Are There Quantum Jumps?” (www2.unicamp.br)

The immediate setting for his 1935 foundational papers was the argument published by Albert Einstein, Boris Podolsky, and Nathan Rosen on 15 May 1935. Their paper, “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?”, considered two systems that had interacted and subsequently separated. Measurements on one could permit certain predictions about the other without directly disturbing it. Using their proposed criterion of physical reality, they argued that the wave function did not provide a complete description. Schrödinger pursued the implications in “Discussion of Probability Relations between Separated Systems” and the three-part German essay Die gegenwärtige Situation in der Quantenmechanik (“The Present Situation in Quantum Mechanics”). (journals.aps.org)

Schrödinger introduced Verschränkung, or entanglement, to describe the resulting inseparability of quantum descriptions. Interaction could leave a composite system with a definite joint wave function while neither component possessed an independent wave function of its own. For a pure joint state, this means that $\Psi(x,y)$ cannot be written as a single product $\psi(x)\phi(y)$ , where $x$ and $y$ denote the coordinates of the respective systems. Even complete knowledge of the whole therefore need not yield complete knowledge of each part. He emphasized that this was not merely a consequence of imperfectly known interactions: it followed from the interaction itself and could persist after separation. (gilles.montambaux.com)

The cat appeared in section 5 of the German essay as a deliberately exaggerated thought experiment, not an animal experiment. A cat was imagined inside a steel chamber containing a radioactive source and a Geiger counter, with equal probabilities of a decay or no decay during one hour. A detection would activate a relay, release a hammer, and break a flask of hydrocyanic acid, killing the cat; without a decay, it would survive. The apparatus thus amplified an atomic alternative into two macroscopically distinct outcomes. Applied to the entire arrangement, the quantum description contained both the living-cat and dead-cat alternatives. (personal.lse.ac.uk)

The difficulty was not ordinary ignorance about an already definite outcome. A coherent superposition retains amplitude relations between alternatives, rather than merely assigning probabilities to independently existing possibilities. Schrödinger used the example to challenge a straightforward identification of the wave function’s indeterminacy with an indeterminate physical reality. In terms of the measurement problem, continuous wave evolution correlates the microscopic system with the detector and cat but does not, by itself, select one observed result. The example exposed that explanatory gap; it was not presented as evidence that an actual cat had been observed simultaneously alive and dead. (personal.lse.ac.uk)

Research beyond the foundational wave equation

Schrödinger’s investigations of color measurement addressed the relationship between physical light stimuli and visual discrimination. His three-part Grundlinien einer Theorie der Farbenmetrik im Tagessehen (“Outline of a Theory of Color Measurement for Daylight Vision”), published in 1920, distinguished two problems. “Lower” color measurement concerned matching: different spectral distributions could produce indistinguishable colors, represented by the same point in a three-dimensional space governed by additive mixture laws. “Higher” color measurement concerned perceived differences, especially the smallest detectable difference between neighboring colors. Following Hermann von Helmholtz, Schrödinger employed a Riemannian metric—a position-dependent rule for measuring distances—to describe perceptual separation rather than merely assign coordinates. His revision sought compatibility with experimental results on brightness additivity and visual sensitivity. (link.springer.com)

A separate 1920 paper, Theorie der Pigmente von größter Leuchtkraft, examined the greatest brightness attainable by a reflecting surface at a specified chromaticity under given illumination. Its idealized “optimal colors” had spectral reflectances taking only the values zero and one: complete absorption or complete reflection at each wavelength. These were mathematical limiting cases, not descriptions of ordinary pigments. His physiological interests also included the eye’s spectral sensitivity and the relationship between three-color and opponent-color theories. In 1925 he showed how their descriptions of color mixtures could be related by a transformation of variables, without thereby establishing that their proposed physiological mechanisms were identical. (link.springer.com)

His work in statistical mechanics and probability included studies of Brownian motion, radioactive-counting fluctuations, and the Gibbs paradox, published between 1915 and 1921. (zbphysik.univie.ac.at) In Über die Umkehrung der Naturgesetze (“On the Reversal of the Laws of Nature,” 1931), he considered particles undergoing diffusion whose spatial distributions were specified at two times. Ordinarily, an initial distribution determines its subsequent spreading through the diffusion equation. Schrödinger instead asked for the most probable intermediate evolution when the final distribution was also known, even if it represented an exceptionally unlikely fluctuation. He combined transition probabilities with particle-counting arguments to determine the likeliest histories compatible with both observations. The problem concerned the time symmetry of statistical inference and the apparent directionality of macroscopic processes, rather than a mechanism for physically reversing time. It became the basis of the Schrödinger bridge problem. (arxiv.org)

Relativistic wave theory provided another continuing research direction. In Diracsches Elektron im Schwerefeld I (“Dirac Electron in the Gravitational Field I,” 1932), Schrödinger investigated how the Dirac equation could be formulated in the curved spacetime of general relativity. The central mathematical difficulty was defining differentiation and parallel transport for an electron’s spinor wave function in a gravitational field. Within the contemporary discussion involving Hermann Weyl and Vladimir Fock, he derived the curvature contribution to the squared Dirac operator: alongside the second-order covariant derivative appears a term proportional to $R/4$ , where $R$ is scalar curvature. This identity, subsequently associated also with André Lichnerowicz, was a definite mathematical result, distinct from the more speculative unification projects he later pursued. (arxiv.org)

During the 1940s, Schrödinger developed unified field theories intended to incorporate gravitation and electromagnetism within one geometrical framework. His affine approach treated the connection—the structure defining parallel transport—as fundamental, rather than beginning solely with the metric defining spacetime intervals. He exchanged calculations and proposals with Albert Einstein, whose own investigations included nonsymmetric geometrical fields. On 27 January 1947, Schrödinger presented a proposed formulation to the Royal Irish Academy after reporting it enthusiastically to Einstein the previous day. Einstein did not accept the announcement as an established physical breakthrough. The equations remained exploratory: obtaining suitable electromagnetic behavior, particle descriptions, and equations of motion proved problematic, and the program produced no experimentally established unification. (link.springer.com)

What Is Life? and the physical study of heredity

Published in 1944, What Is Life? The Physical Aspect of the Living Cell developed public lectures delivered at Trinity College, Dublin, in February 1943 under the auspices of the Dublin Institute for Advanced Studies. Schrödinger addressed a physical puzzle: how could hereditary structures containing comparatively few atoms remain stable across generations, despite thermal agitation, while directing an organism’s development? Ordinary macroscopic regularities often depend on averaging over enormous numbers of particles; heredity appeared to require reliable behavior from much smaller structures. His question concerned both the persistence of hereditary information and the maintenance of biological organization, rather than simply a definition of life. (inist.org)

Schrödinger described the hereditary material in a chromosome as an “aperiodic crystal.” Unlike a conventional crystal, whose elementary pattern repeats, this structure could have a stable but nonrepetitive arrangement capable of embodying many different instructions. His “code-script” metaphor connected that structural variety with the specification of development. For molecular stability and mutation, he drew explicitly on Max Delbrück’s model: a gene was envisaged as a large molecule whose alternative atomic configurations were separated by substantial energy barriers. Ordinary thermal motion would seldom overcome those barriers, preserving the hereditary configuration; a rare transition could produce a lasting change. This was a general physical model, not an identification of DNA as the hereditary substance or a prediction of its double-helical geometry. (assets.cambridge.org)

The phrase “order from order” distinguished the transmission of an existing, highly specific molecular arrangement from the statistical regularities Schrödinger called “order from disorder.” The latter included familiar physical laws emerging from the collective behavior of numerous particles; the former emphasized how a small hereditary structure could govern much larger biological processes. Nevertheless, Schrödinger acknowledged that a general molecular picture could not explain how hereditary instructions were implemented. In chapter 6 he assigned the detailed investigation of that mechanism to biochemistry, guided by physiology and genetics, rather than claiming that physics alone had already solved it. (inist.org)

His discussion of “negative entropy” addressed how an organism avoids thermodynamic equilibrium, not how it escapes the second law of thermodynamics. An organism maintains its internal organization through exchanges with its surroundings, consuming resources and releasing heat and degraded products; its internal entropy need not increase continuously because it is not isolated. Entropy produced in its processes is transferred to the environment. In a note to chapter 6, Schrödinger explained that a discussion intended specifically for physicists would instead have used free energy. “Negative entropy” therefore described the environmental support required for continued organization, not a special biological substance or a suspension of thermodynamic law. (inist.org)

The book’s influence on molecular biology is documented in the testimony of Francis Crick and James Watson. On 12 August 1953, after their DNA-structure paper had appeared in Nature on 25 April, Crick wrote to Schrödinger that both researchers had been influenced by the book. Watson likewise recalled in DNA: The Secret of Life that reading it during his third year at the University of Chicago redirected his interests from natural history toward the gene, particularly the problem of storing and copying biological information. These accounts establish an inspirational role, not experimental priority: the book neither determined DNA’s structure nor deciphered the genetic code. Its general code-script metaphor must be distinguished from the later technical identification of how nucleotide sequences specify proteins. (nobelprize.org)

Philosophy, consciousness, and scientific knowledge

In Science and Humanism: Physics in Our Time (1951), Schrödinger examined how modern physics had altered the relationship between scientific descriptions and their objects. He rejected the assumption that a model drawn from everyday experience could become a literal picture of microscopic reality simply through refinement. His discussion of causality likewise distinguished a precisely formulated physical principle from a general demand that events have causes. Classical field physics described the state at a place and time as determined by preceding conditions in its neighbourhood, expressing this dependence through differential equations. Abandoning an uninterrupted description therefore threatened that particular formulation of causality; it did not, in his presentation, settle every philosophical question about causal explanation. (api.pageplace.de)

Nature and the Greeks (1954) approached the assumptions of science through the intellectual inheritance of ancient Greece. Schrödinger identified two especially consequential commitments: that nature is intelligible, and that knowledge can be constructed by separating the knowing subject from the world described. He called the latter procedure “objectivation.” Returning to Greek thought made these commitments available for examination rather than leaving them as unnoticed habits of modern inquiry. In Mind and Matter, he explicitly clarified that he was describing historically inherited principles of scientific practice, not prescribing foundations that science must preserve at all costs. His philosophy of science thus questioned the scope of objectivity without simply rejecting objective investigation. (api.pageplace.de)

Mind and Matter (1958), based on the Tarner Lectures delivered at Trinity College, Cambridge, in October 1956, developed the consequences for perception and consciousness. Objectivation, in his account, removes the experiencing subject from the scientific picture even though experience supplies the material from which that picture is constructed. This produces a difficulty: the observer’s body can appear among the objects described, while the experiencing self does not appear in the same manner. In the chapter “The Arithmetical Paradox: The Oneness of Mind,” he considered how numerous apparently private fields of experience yield one shared world. Their overlapping contents support the construction of a common external reality, but leave questions about the relation between that reality and individual experience. These were arguments in epistemology and philosophy of mind, rather than experimentally demonstrated consequences of quantum mechanics. (zbphysik.univie.ac.at)

His criticism of mind–matter dualism received a direct formulation in My View of the World, published in English in 1964 in Cecily Hastings’s translation. Its two essays were written thirty-five years apart; Schrödinger’s foreword, dated July 1960, located the earlier essay before his development of wave mechanics. In “Reasons for abandoning the dualism of thought and existence, or mind and matter,” he challenged the supposed obviousness of interaction between two fundamentally different domains. If an immaterial will changes material events, he argued, the physical sequence ceases to be autonomous; conversely, describing light striking an eye or vibrations reaching an ear does not explain how a material event becomes a sensation. (api.pageplace.de)

The alternative explored in these writings was a doctrine of identity or non-plurality, connected explicitly with Vedānta, rather than a physical mechanism linking two substances. My View of the World included chapters entitled “The Vedantic vision,” “More about non-plurality,” and “The doctrine of identity: light and shadow.” These commitments belonged to his metaphysics: they concerned what subject and world ultimately are, not additional terms in the Schrödinger equation or experimentally measurable predictions derived from it. His foreword distinguished the formulation of a philosophical world-view from the work of physics, preserving that difference even while treating both as legitimate intellectual pursuits. (api.pageplace.de)

Dublin research life and the return to Vienna

Schrödinger lived in Dublin from 1939 until 1956, making Ireland his longest place of residence after leaving Austria. As Senior Professor and the first director of the School of Theoretical Physics at the Dublin Institute for Advanced Studies (DIAS), he combined research with the establishment of an advanced teaching programme. Initially the school consisted of Schrödinger alone; in February 1941 he moved into its premises at 65 Merrion Square. Walter Heitler joined as Assistant Professor in June 1941, and John Lighton Synge became Senior Professor in 1948. The directorship was not Schrödinger’s uninterrupted responsibility: Heitler took it over in December 1945, and Schrödinger resumed it after Heitler’s departure in October 1949. (zbphysik.univie.ac.at)

His teaching connected the research institute with Dublin’s universities. Before the Merrion Square premises were ready, he gave two courses on quantum theory at the Royal Irish Academy. The introductory course covered wave mechanics, perturbation theory, electron spin, and the Dirac equation; advanced seminars introduced the school’s current research, including general relativity. Senior university students attended alongside research scholars. Public communication was also an institutional duty: the school’s establishment order required public lectures, alternating between University College Dublin and Trinity College Dublin. Schrödinger’s 1943 lectures at Trinity, subsequently published as What Is Life? in 1944, attracted an audience of nearly 400, requiring the lectures to be repeated. His Dublin work therefore extended beyond specialist investigation to advanced instruction and public scientific writing. (stp.dias.ie)

After the Second World War, Schrödinger indicated his willingness to return to the University of Vienna, but an immediate appointment did not follow. The university’s institutional history identifies his fear of being taken to the Soviet Union as one reason for his hesitation. Meanwhile, he renewed Austrian academic contacts without initially abandoning his Dublin position. Arthur March secured his visiting professorship at the University of Innsbruck for 1950–51. There Schrödinger delivered a five-hour lecture course on unified field theory, with Ferdinand Cap assigned as his assistant. He also participated in an interdisciplinary seminar with Wolfgang Stegmüller and other Innsbruck colleagues, linking his renewed Austrian teaching with his continuing philosophical interests. (geschichte.univie.ac.at)

In 1955 Schrödinger informed DIAS that he wished to resign because of ill health. His permanent return to Austria followed in 1956, when he took up a specially created position as Extraordinarius in physics at the University of Vienna, effective from 1 January. This was a new appointment rather than the restoration of his prewar honorary professorship. He continued lecturing at Vienna for another two years. (stp.dias.ie)

Schrödinger died in Vienna on 4 January 1961, aged 73. He was buried not in Vienna but in Alpbach, the Tyrolean village he had come to know through its academic meetings and used as a summer residence during his later years. Burial there followed his own wishes. (geschichte.univie.ac.at)

Honors, scientific legacy, and historical sources

Schrödinger’s distinctions beyond the Nobel Prize in Physics included the Vienna Academy’s Haitinger Prize in 1920, the Matteucci Medal in 1930, and the Max Planck Medal in 1937. Following his permanent return to Austria, he received the City of Vienna’s award for natural sciences in 1956 and the Austrian Decoration for Science and Art in 1957. The Austrian government established the Erwin Schrödinger Prize through a ministerial decree dated 30 April 1956, entrusting it to the Austrian Academy of Sciences; Schrödinger himself was its first recipient. Its founding purpose was to recognize outstanding achievements by scholars working in Austria in disciplines represented broadly by the Academy’s mathematical and natural-sciences division, rather than exclusively in theoretical physics. (geschichte.univie.ac.at)

His scientific legacy rests principally on the continuing use of the Schrödinger equation, not simply on the historical recognition of its author. Wave mechanics supplies a framework for calculating atomic energy levels and spectra and, through approximations and generalizations, molecular electronic structures and chemical behavior. Its importance therefore extends from spectroscopy to quantum chemistry and materials research. The University of Vienna’s centenary account emphasizes that the equation remains a working research instrument: practical calculations refine or approximate the mathematical framework rather than treating the original 1926 solutions as a completed theory of every physical system. (schroedinger100.univie.ac.at)

The connection to later technologies is foundational rather than a claim of direct invention. Lasers belong to the technological developments underpinned by quantum descriptions of matter and radiation. Magnetic resonance imaging likewise depends on quantum physics, particularly the behavior of nuclear spin in magnetic fields. Radiofrequency pulses disturb the equilibrium magnetization of hydrogen nuclei, and the resulting signals vary with their molecular environment, enabling tissue differentiation. These applications required additional discoveries, experimental techniques, and engineering; neither device should be attributed to Schrödinger personally, nor should MRI be presented as an application of his original scalar wave equation alone. (schroedinger100.univie.ac.at)

Public commemoration took forms distinct from these scientific uses. His portrait appeared on Austria’s 1,000-schilling banknote in 1983. At the University of Vienna, a monument by Ferdinand Welz was unveiled in the arcaded courtyard in 1984; since 2006, Schrödinger has also been represented in the installation Nobel Prize and University of Vienna—Group Picture with Question Mark. Such objects document his place in Austrian public and institutional memory, whereas assessments of his scientific contribution depend on the content, reception, and subsequent use of his research. (geschichte.univie.ac.at)

The principal documentary holdings are preserved at the University of Vienna’s Austrian Central Library for Physics. Its Schrödinger collections comprise approximately 2,000 items, including notebooks, research and teaching files, correspondence, manuscripts, drafts, photographs, and memorabilia; digitized materials are accessible through the university’s PHAIDRA repository. The online publication bibliography, compiled by Auguste Dick, Gabriele Kerber, Wolfgang Kerber, and Karl von Meyenn, separates papers from books and records translations, reprints, and cross-references. These resources support different kinds of historical reconstruction: notebooks preserve intermediate calculations, letters reveal exchanges with contemporaries, and bibliographic records distinguish original publication from later circulation. The university’s archival exhibition, for example, juxtaposes the 1926 wave-mechanics papers with notebooks and correspondence involving Hans Thirring, Albert Einstein, and Max Planck, allowing the published theory to be studied alongside its development and early reception. (services.phaidra.univie.ac.at)

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