Erwin Schrodinger

Erwin Schrodinger (1887 to 1961) was the Austrian physicist who in 1926 wrote the wave equation that bears his name, the central equation of quantum mechanics. It describes how the wave function of a quantum system evolves in time, giving physicists a way to compute the behavior of atoms and molecules. He shared the Nobel Prize in Physics for 1933 with Paul Dirac, and is also known for the Schrodinger's cat thought experiment.

#The wave equation

In a series of papers in 1926 Schrodinger developed wave mechanics, treating particles such as electrons as governed by a continuous wave function rather than fixed orbits. His equation relates the rate of change of the wave function to the system's energy, and its solutions reproduced the spectral lines of hydrogen and the quantized energy levels of atoms. The Nobel committee awarded the 1933 prize "for the discovery of new productive forms of atomic theory" (Nobel Prize facts). His formulation was quickly shown to be mathematically equivalent to the matrix mechanics of Werner Heisenberg, and its more intuitive picture made it the working tool of most physicists.

#Interpreting the wave function

Schrodinger initially hoped the wave function represented a real physical field, but Max Born's rule reinterpreted its squared magnitude as a probability, a reading Schrodinger resisted. The gap between the smooth, deterministic evolution of the wave function and the definite outcomes seen on measurement is at the heart of the measurement problem and of debates over the Copenhagen interpretation.

#Schrodinger's cat and entanglement

In 1935 Schrodinger published a paper responding to the argument of Albert Einstein and colleagues. In it he introduced the Schrodinger's cat thought experiment, in which a cat is linked to a random quantum event so that the formalism, taken literally, would leave it in a superposition of alive and dead. The same paper coined the term entanglement (Verschrankung in German) for the correlations he called the characteristic trait of quantum mechanics (SEP: quantum entanglement). Both ideas became central to later work on quantum entanglement and the foundations of the theory.

#Significance

The Schrodinger equation is one of the most widely used tools in physics and chemistry, underpinning the modern theory of atoms, molecules, and solids. His cat and his naming of entanglement made him, like Einstein, both a founder of quantum mechanics and a probing critic of how it should be understood.

#History

Schrodinger was born in Vienna in 1887 and did his prize-winning work while at the University of Zurich and then Berlin (Nobel biographical). He left Germany in 1933, later helped establish the Dublin Institute for Advanced Studies in Ireland, and wrote the influential 1944 book What Is Life. He returned to Vienna near the end of his career and died there in 1961.