Oskar Benjamin Klein (; 15 September 1894 – 5 February 1977) was a Swedish

theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimen ...

Biography

Klein was born in

Danderyd Danderyd Municipality (''Danderyds kommun''; ) is a municipality north of Stockholm in Stockholm County in east central Sweden. It is one of the smallest municipalities of Sweden, but the most affluent. Its seat is located in Djursholm and it is ...

outside

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

, son of the chief rabbi of Stockholm, Gottlieb Klein from

Humenné Humenné (; hu, Homonna; ukr, Гуменне) is a town in the Prešov Region ("kraj") in eastern Slovakia and the second largest town of the historic Zemplín region. It lies at the volcanic Vihorlat mountains and at the confluence of the ...

Kingdom of Hungary The Kingdom of Hungary was a monarchy in Central Europe that existed for nearly a millennium, from the Middle Ages into the 20th century. The Principality of Hungary emerged as a Christian kingdom upon the coronation of the first king Stephen ...

, now

Slovakia Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the s ...

and Antonie (Toni) Levy. He became a student of

Svante Arrhenius Svante August Arrhenius ( , ; 19 February 1859 – 2 October 1927) was a Swedes, Swedish scientist. Originally a physicist, but often referred to as a chemist, Arrhenius was one of the founders of the science of physical chemistry. He received ...

at the

Nobel Institute The Norwegian Nobel Institute ( no, Det Norske Nobelinstitutt) is located in Oslo, Norway. The institute is located at Henrik Ibsen Street 51 in the center of the city. It is situated just by the side of the Royal Palace. History The institute ...

at a young age and was on the way to

Jean-Baptiste Perrin Jean Baptiste Perrin (30 September 1870 – 17 April 1942) was a French physicist who, in his studies of the Brownian motion of minute particles suspended in liquids ( sedimentation equilibrium), verified Albert Einstein’s explanation of this ...

in France when

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

broke out and he was drafted into the military. From 1917, he worked a few years with

Niels Bohr Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. B ...

in the

University of Copenhagen The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in ...

and received his doctoral degree at the University College of Stockholm (now

Stockholm University Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, so ...

) in 1921. In 1923, he received a professorship at

University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...

Ann Arbor Anne, alternatively spelled Ann, is a form of the Latin female given name Anna (name), Anna. This in turn is a representation of the Hebrew Hannah (given name), Hannah, which means 'favour' or 'grace'. Related names include Annie (given name), ...

and moved there with his recently wedded wife, Gerda Koch from

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...

. Klein returned to Copenhagen in 1925, spent some time with

Paul Ehrenfest Paul Ehrenfest (18 January 1880 – 25 September 1933) was an Austrian theoretical physicist, who made major contributions to the field of statistical mechanics and its relations with quantum mechanics, including the theory of phase transition a ...

Leiden Leiden (; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 119,713, but the city forms one densely connected agglomeration wit ...

, then became

docent The title of docent is conferred by some European universities to denote a specific academic appointment within a set structure of academic ranks at or below the full professor rank, similar to a British readership, a French " ''maître de conf ...

Lund University , motto = Ad utrumque , mottoeng = Prepared for both , established = , type = Public research university , budget = SEK 9 billion Erik Ivar Fredholm Erik Ivar Fredholm (7 April 1866 – 17 August 1927) was a Swedish mathematician whose work on integral equations and operator theory foreshadowed the theory of Hilbert spaces. Biography Fredholm was born in Stockholm in 1866. He obtained his P ...

until his death in 1927. Klein was awarded the

Max Planck Medal The Max Planck medal is the highest award of the German Physical Society , the world's largest organization of physicists, for extraordinary achievements in theoretical physics. The prize has been awarded annually since 1929, with few exceptions, ...

in 1959. He retired as professor emeritus in 1962. Klein is credited for inventing the idea, part of Kaluza–Klein theory, that extra

dimension In physics and mathematics, the dimension of a Space (mathematics), mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any Point (geometry), point within it. Thus, a Line (geometry), lin ...

s may be physically real but curled up and very small, an idea essential to

string theory In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interac ...

. In 1938, he proposed a boson-exchange model for charge-charging weak interactions (radioactive decay), a few years after a similar proposal by

Hideki Yukawa was a Japanese theoretical physicist and the first Japanese Nobel laureate for his prediction of the pi meson, or pion. Biography He was born as Hideki Ogawa in Tokyo and grew up in Kyoto with two older brothers, two older sisters, and two yo ...

. His model was based on a local isotropic gauge symmetry and anticipated the later successful theory of Yang–Mills. The

Oskar Klein Memorial Lecture The Oskar Klein Memorial Lecture at Stockholm University, dedicated to the memory of the Swedish physicist Oskar Klein (1894-1977), is held annually since 1988 by a prominent physicist, who also receives the Oskar Klein Medal. The lecture is spons ...

, held annually at the University of Stockholm, has been named after him. The Oskar Klein Centre for Cosmoparticle Physics in Stockholm, Sweden is also in his honor. Oskar Klein is the grandfather of Helle Klein.

References

External links

* Oskar Klein; The Atomicity of Electricity as a Quantum Theory Law, Nature 1926, 118 (516) - doi =
10.1038/118516a0
, *Oskar Klein; Quantentheorie und fünfdimensionale relativitätstheorie - Surveys in High Energy Physics, https://doi.org/10.1080/01422418608228771 * {{DEFAULTSORT:Klein, Oskar 1894 births 1977 deaths Swedish physicists Jewish physicists Theoretical physicists Stockholm University alumni Members of the Royal Swedish Academy of Sciences Swedish Jews Hungarian Jews Winners of the Max Planck Medal University of Michigan faculty Burials at Norra begravningsplatsen