Hendrik Brugt Gerhard Casimir (15 July 1909 – 4 May 2000) was a Dutch

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

best known for his research on the two-fluid model of

superconductors Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...

(together with

C. J. Gorter Cornelis Jacobus (Cor) Gorter (14 August 1907, Utrecht – 30 March 1980, Leiden) was a Dutch experimental and theoretical physicist. Among other work, he discovered paramagnetic relaxation and was a pioneer in low temperature physics. Education ...

) in 1934 and the

Casimir effect In quantum field theory, the Casimir effect is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of the field. It is named after the Dutch physicist Hendrik Casimir, who pre ...

(together with D. Polder) in 1948.

Biography

Casimir was born 15 July 1909. He studied theoretical physics at the

University of Leiden Leiden University (abbreviated as ''LEI''; nl, Universiteit Leiden) is a public research university in Leiden, Netherlands. The university was founded as a Protestant university in 1575 by William, Prince of Orange, as a reward to the city of Le ...

under

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 ...

, where he received his Ph.D. in 1931. His Ph.D. thesis dealt with the quantum mechanics of a rigid spinning body and the group theory of the rotations of molecules. During that time he also spent some time in Copenhagen 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 ...

, where he helped Bohr support the latter's hypothesis of the " gunslinger effect" with mock shoot-outs on campus. From 1932 to mid-1933, Casimir worked as an assistant to

Wolfgang Pauli Wolfgang Ernst Pauli (; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics ...

ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , a ...

. During this period, he worked on the relativistic theory of the electron, in particular, evaluating deviations of the Klein-Nishina equation in the case of bound electrons. To attack the problem, he invented a number of mathematical tools. One in particular is still referred to as the “Casimir Trick": in particle interaction calculations, it is a familiar procedure of trace formation and projections using products of Dirac matrices. In 1938, Casimir became a physics professor at

Leiden University Leiden University (abbreviated as ''LEI''; nl, Universiteit Leiden) is a public research university in Leiden, Netherlands. The university was founded as a Protestant university in 1575 by William, Prince of Orange, as a reward to the city o ...

. At that time, he was actively studying both

heat conduction Conduction is the process by which heat is transferred from the hotter end to the colder end of an object. The ability of the object to conduct heat is known as its ''thermal conductivity'', and is denoted . Heat spontaneously flows along a te ...

and

electrical conduction Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows ...

, and contributed to the attainment of millikelvin temperatures. In 1942, during World War II, Casimir moved to the

Philips Natuurkundig Laboratorium The Philips Natuurkundig Laboratorium (English translation: ''Philips Physics Laboratory'') or NatLab was the Dutch section of the Philips research department, which did research for the product divisions of that company. Originally located in the ...

(Philips Physics Laboratory, NatLab) in

Eindhoven Eindhoven () is a city and municipality in the Netherlands, located in the southern province of North Brabant of which it is its largest. With a population of 238,326 on 1 January 2022,Lars Onsager Lars Onsager (November 27, 1903 – October 5, 1976) was a Norwegian-born American physical chemist and theoretical physicist. He held the Gibbs Professorship of Theoretical Chemistry at Yale University. He was awarded the Nobel Prize in C ...

's principle of microscopic reversibility. He became a co-director of Philips NatLab in 1946 and a member of the board of directors of the company in 1956. He retired from Philips in 1972. Although he spent much of his professional life in industry, Hendrik Casimir was one of the great Dutch theoretical physicists. Casimir made many contributions to science during his years in research from 1931 to 1950. These contributions include: pure mathematics,

Lie group In mathematics, a Lie group (pronounced ) is a group that is also a differentiable manifold. A manifold is a space that locally resembles Euclidean space, whereas groups define the abstract concept of a binary operation along with the addi ...

s (1931);

hyperfine structure In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate energy levels and the resulting splittings in those energy levels of atoms, molecules, and ions, due to electromagnetic multipole interaction between the n ...

, calculation of nuclear quadrupole moments, (1935); low temperature physics, magnetism, thermodynamics of superconductors, paramagnetic relaxation (1935–1942); applications of Onsager's theory of irreversible phenomena (1942–1950). He helped found the

European Physical Society The European Physical Society (EPS) is a non-profit organisation whose purpose is to promote physics and physicists in Europe through methods such as physics outreach. Formally established in 1968, its membership includes the national physical so ...

and became its president from 1972 till 1975. In 1979 he was one of the key speakers at CERN's 25th anniversary celebrations. In 1946 he became member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...

. While at

Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters is ...

NatLab, in 1948 Casimir, collaborating with

Dirk Polder Dirk Polder (23 August 1919 – 18 March 2001) was a Dutch physicist who, together with Hendrik Casimir, first predicted the existence of what today is known as the Casimir-Polder force, sometimes also referred to as the ''Casimir effect ...

, predicted the

quantum mechanical Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, qua ...

attraction between conducting plates now known as the

, which has important consequences in Micro Electro-Mechanical Systems (MEMS), among others. He was awarded six honorary doctor degrees by universities outside the Netherlands. He received numerous awards and prizes, among them the illustrious

IRI Medal The IRI Medal, established by the Industrial Research Institute (IRI) in 1946, recognizes and honors leaders of technology for their outstanding accomplishments in technological innovation which contribute broadly to the development of industry and ...

from the

Industrial Research Institute Innovation Research Interchange (IRI) is a division of the National Association of Manufacturers, a nonprofit association based in Washington, D. C., United States. IRI was founded as a private non-profit in 1938 and merged with the NAM in 2022. I ...

in 1976. He was a Foreign Associate of the

National Academy of Engineering The National Academy of Engineering (NAE) is an American nonprofit, non-governmental organization. The National Academy of Engineering is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of ...

. In 1982, he was awarded the

Wilhelm Exner Medal The Wilhelm Exner Medal has been awarded by the Austrian Industry Association, (ÖGV), for excellence in research and science since 1921. The medal is dedicated to Wilhelm Exner (1840–1931), former president of the Association, who initialize ...

. He was an elected member of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, a ...

, the United States

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nat ...

, and the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

Publications

* * H. B. G. Casimir, ''Haphazard Reality: half a century of science'' (Harper & Row, New York, 1983); Casimir's autobiography in English. * H. B. G. Casimir, ''Het toeval van de werkelijkheid: Een halve eeuw natuurkunde'' (Meulenhof, Amsterdam, 1992); Casimir's autobiography in Dutch. * * H. B. G. Casimir,
On the attraction between two perfectly conducting plates
', Proceedings of the Royal Netherlands Academy of Arts and Sciences, Vol. ''51'', pp. 793–795 (1948). * H. B. G. Casimir, and J. Ubbink,
The Skin Effect
, "Philips Technical Review", Vol. ''28'', pp; 300–315 (1967)

Notes and references

External links

PhysicsWeb article
on the Casimir Effect
The Casimir Force
* C. J. Gorter, ''C. J. Gorter's life & science'',

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 w ...

The Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

Oral History interview transcript with Hendrik Casimir on 5 July 1963, American Institute of Physics, Niels Bohr Library & Archives
- Session I
Oral History interview transcript with Hendrik Casimir on 6 July 1963, American Institute of Physics, Niels Bohr Library & Archives
- Session II * {{DEFAULTSORT:Casimir, Hendrik 1909 births 2000 deaths 20th-century Dutch physicists Leiden University alumni Leiden University faculty Members of the Royal Netherlands Academy of Arts and Sciences Foreign associates of the National Academy of Sciences Foreign associates of the National Academy of Engineering Recipients of the Pour le Mérite (civil class) Scientists from The Hague Foreign Members of the Royal Society Members of the German Academy of Sciences at Berlin Recipients of the Matteucci Medal Presidents of the European Physical Society Members of the American Philosophical Society

Biography

Publications

Notes and references

Further reading

External links