User:Abt 12/Jordan sandbox
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| Pascual Jordan | |
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| Born | October 18, 1902 Hanover, Germany |
| Died | July 31, 1980 Hamburg, Germany |
Ernst Pascual Jordan (October 18, 1902 – July 31, 1980) was a German scientist who worked in the fields of physics, mathematics, microbiology and meteorology. He was also a politician for a brief time.
Jordan collaborated with Max Born and Werner Heisenberg on an important series of papers which established the matrix mechanics formalism of quantum mechanics. He went on to pioneer early quantum field theory before switching to microbiology where he met with little success. A nationalist and anti-communist, Jordan joined the Nazi Party and the Sturmabteilung the year Adolf Hitler assumed power in Germany. He spent World War II doing meteorological work for the German air force and navy while trying unsucessfully to get support for weapons-related physical research. While he was pronounced politically rehabilitated and allowed back into a university post after the war; his Nazi past permanently affected his standing in the scientific community. Jordan was elected to a seat in the German federal parliment as a Christian Democrat for a single term. In his later years, Jordan did significant work in cosmology and gravitation.
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[edit] Biography
[edit] Ancestry and student years
Jordan's great-grandfather Pascual Jorda was a Spanish nobleman and cavalry officer who served during the Napoleonic Wars and eventually settled in Hanover. Jorda's patrilineal descendants would hold to a tradition of naming their first-born sons Pascual, while their family name was eventually changed to Jordan (which is pronounced in the German manner: "YOUR-den").
Jordan enrolled in the University of Hanover in 1921 where he studied an eclectic mix of zoology, mathematics, and physics. As was typical for a German university student of the time, he transferred before obtaining a degree there. Georg August University of Göttingen, his destination in 1923, was at the zenith of its prowess and fame in mathematics and the physical sciences. Here, Jordan became an assistant to the mathematician Richard Courant, helping put together the
Courant and Hilbert, Methods of Mathematical Physics, 1924 (revised for a second and final time by Courant in 1953)
Writing together with James Franck: Annregung von Quantumsprüngen durch Stoesse, 1926.
By the end of this association with Courant, Jordan would have a strong command of mathematics, algebra in particular. Linear algebra was not very well known among theoretical physicists of the time and abstract algebra even moreso.
became the assistant of Max Born, who was the chairman of the Göttingen physics department.
Jordan recieved a Ph.D. for his dissertation Zur Theorie der Quantenstrahlung in 1925.
[edit] Matrix mechanics
In June, 1925, Werner Heisenberg concieved the rudiments of matrix mechanics while recovering from a bad bout of hay fever on the island of Helgoland in the North Sea. Heisenberg was only 23 years old, a freshly-minted Ph.D. and student of Arnold Sommerfeld who had begun a collaboration with Niels Bohr.
Heisenberg approached Max Born with his new theory.
Jordan wrote a paper developing Fermi-Dirac statistics, however Born lost the manuscript within one of his suitcases. By the time Born discovered this mishap, papers by Fermi and Dirac had already been published and Jordan lost priority on the discovery.
[edit] Quantum field theory
The non-associative Jordan algebras are named after him. They were defined in an attempt to create an algebra of observables for quantum mechanics and quantum field theory. Today, this role is more often assumed by the von Neumann algebras. Meanwhile, Jordan algebras have seen application in projective geometry and number theory.
[edit] Political activities and World War II
Jordan joined the NSDAP (Nazi Party) in May 1933. The following November he joined the Sturmabteilung (SA) - the brown shirted storm troopers. He enlisted in the Luftwaffe in 1939 and worked for a while at the Peenemünde rocket center. During the war he attempted to interest the party in various schemes for advanced weapons, but these were ignored because he was considered "politically unreliable", probably because of his past associations with Jews (in particular: Courant, Born, and Wolfgang Pauli) and "Jewish Physics" (such a stigma also followed Werner Heisenberg for some time under the Nazis)(see the article Deutsche Physik).
It has been speculated that Jordan would have likely shared the 1954 Nobel Prize in Physics awarded to Max Born were it not for his membership in the Nazi party (see both J. Bernstein and B. Schroer references).
[edit] Post-war years
Wolfgang Pauli declared Jordan "rehabilitated" to the authorities some time after the war, allowing Jordan to regain academic employment after a two-year period and then recover his full status as a tenured professor in 1953. Jordan went against Pauli's advice, and reentered politics after the period of denazification came to an end under the pressures of the Cold War. He secured election to the Bundestag standing with the conservative Christian Democrats. In 1957, Jordan came out in support for the arming of the Bundeswehr with tactical nuclear weapons by the Adenauer government, while the Göttinger 18 (which included Born, Heisenberg, and Pauli) authored the Göttinger Manifest in protest.
from Golden age of general relativity...
- "1961: Pascual Jordan and Jürgen Ehlers develop the kinematic decomposition of a timelike congruence"
from Scalar theories of gravitation...
- "Kaluza-Klein theory involves the use of a scalar gravitional field in addition to the electromagnetic field potential Aμ in an attempt to create a five-dimensional unification of gravity and electromagnetism. Its generalization with a 5th variable component of the metric that leads to a variable gravitational constant was first given by Pascual Jordan." (see Brans gr-qc/0506063)
- "Brans-Dicke theory is a scalar-tensor theory, not a scalar theory, meaning that it represents the gravitational interaction using both a scalar field and a tensor field. We mention it here because one of the field equations of this theory involves only the scalar field and the trace of the stress-energy tensor, as in Nördstrom's theory. Moreover, the Brans-Dicke theory is equal to the independently derived theory of Jordan (hence it is often referred to as the Jordan-Brans-Dicke or JBD theory). The Brans-Dicke theory couples a scalar field with the curvature of space-time and is self-consistent and, assuming appropriate values for a tunable constant, this theory has not been ruled out by observation. The Brans-Dicke theory is generally regarded as a leading competitor of general relativity ,which is a pure tensor theory. However, the Brans-Dicke theory seems to need too high a parameter, which favours general relativity)."
[edit] Selected works by Pascual Jordan
[edit] Books
- Elementare Quantenmechanik (with Max Born), 1930
- Statistische Mechanik auf quantentheoretischer Grundlage, 1933
- Atom und Weltall, 1936
- Die Physik und das Geheimnis des organischen Lebens, 1941
- Die Expansion der Erde, 1966
- Albert Einstein, 1969
[edit] Scientific papers
- The "Dreimännerarbeit"
- Jordan algebra paper with von Neumann and Wigner
[edit] Notes
[edit] References
- B. Schroer, "Pascual Jordan, his contributions to quantum mechanics and his legacy in contemporary local quantum physics", arXiv:hep-th/0303241
- J. Bernstein, "Max Born and the Quantum Theory", American Journal of Physics, 11 (2005), 999-1008).
