{{short description|German-American mathematician and physicist (1908–1989)}} {{Infobox scientist | name = Valentine Bargmann | birth_name = | image = | image_size = | alt = | caption = | birth_date = {{birth date|1908|4|6|df=y}} | birth_place = [[Berlin]], [[Kingdom of Prussia|Prussia]], [[German Empire|Germany]] | death_date = {{death date and age|1989|7|20|1908|4|6|df=y}} | death_place = [[Princeton, New Jersey]], [[USA]] | death_cause = | resting_place = | other_names = | residence = | citizenship = | nationality = | fields = [[Physics]] | workplaces = [[Princeton University]] | patrons = | education = | alma_mater = [[University of Berlin]] | thesis_title = Über die durch Elektronenstrahlen in Kristallen angeregte Lichtemission | thesis_url = https://uzb.swisscovery.slsp.ch/permalink/41SLSP_UZB/1d8t6qj/alma990075789330205508 | thesis_year = 1937 | doctoral_advisor = [[Gregor Wentzel]] | academic_advisors = | doctoral_students = | notable_students = | known_for = [[Galilean_transformation#Central_extension_of_the_Galilean_group|Bargmann algebra]]<br>[[Oscillator_representation#Holomorphic_Fock_space|Bargmann kernel]]<br>[[Bargmann's limit]]<br>[[Projective_representation#Infinite-dimensional_projective_unitary_representations:_Bargmann's_theorem|Bargmann's theorem]]<br>[[Bargmann–Wigner equations]]<br>{{no wrap|[[Larmor_precession#Bargmann–Michel–Telegdi_equation|Bargmann–Michel–Telegdi equation]]}}<br>[[Segal–Bargmann space]]<br>[[Representation theory of SL2(R)]] | influences = | influenced = | awards = [[Max Planck Medal]] (1988)<br>[[International_Colloquium_on_Group_Theoretical_Methods_in_Physics#Wigner_Medal|Wigner Medal]] (1978) | spouse = | partner = | children = | signature = | signature_alt = | website = | footnotes = }} '''Valentine''' "'''Valya'''" '''Bargmann''' (April 6, 1908 – July 20, 1989)<ref name="Great">{{cite book |year=1999 |url=https://books.google.com/books?isbn=0309064341 |chapter=Valentine Bargmann |title=Biographical Memoirs, Vol. 76 |pages=37–50 |publisher=National Academy Press|isbn=0-309-06434-1}}</ref> was a German-American [[mathematician]] and theoretical [[physicist]].

==Biography== Born in Berlin, [[German Empire|Germany]], to a [[History of the Jews in Germany|German Jewish]] family, Bargmann studied there from 1925 to 1933. After the National Socialist [[Machtergreifung]], he moved to Switzerland to the [[University of Zürich]] where he received his Ph.D. under [[Gregor Wentzel]].

He emigrated to the U.S., barely managing immigration acceptance, as his German passport was to be revoked with only two days of validity left.

At the [[Institute for Advanced Study]] in [[Princeton, New Jersey|Princeton]] (1937–1946) he worked as an assistant to [[Albert Einstein]],<ref>Witten, E. (2014). "A Note On Einstein, Bergmann, and the Fifth Dimension", {{arXiv|1401.8048}}</ref> publishing with him and [[Peter Bergmann]] on classical five-dimensional [[Kaluza–Klein theory]] (1941). He taught at [[Princeton University]] from 1946 for the rest of his career.

He pioneered understanding of the [[representation theory of SL2(R)|irreducible unitary representations of SL<sub>2</sub>('''R''')]] and the [[representations of the Lorentz group|Lorentz group]] (1947). He further formulated the [[Bargmann–Wigner equations]] with [[Eugene Wigner]] (1948), for particles of arbitrary spin, building up on work of several theorists who pioneered [[quantum mechanics]].<ref>V. Bargmann [https://www.jstor.org/stable/1969129 ''Irreducible Unitary Representations of the Lorentz Group''] The Annals of Mathematics 2nd Ser., Vol. 48, No. 3 (Jul., 1947), pp. 568-640</ref><ref>{{cite journal|author1=Bargmann, V.|author2=Wigner, E. P.|title=Group theoretical discussion of relativistic wave equations|year=1948|journal=Proc. Natl. Acad. Sci. USA|volume=34|pages=211–23|issue=5|doi=10.1073/pnas.34.5.211|pmid=16578292|bibcode=1948PNAS...34..211B|pmc=1079095|doi-access=free}}</ref>

[[Projective representation#Infinite-dimensional projective unitary representations: Bargmann's theorem|Bargmann's theorem]] (1954) on projective unitary representations of [[Lie group]]s gives a condition for when a projective unitary representation of a Lie group comes from an ordinary unitary representation of its universal cover.

Bargmann further discovered the [[Larmor precession#Bargmann–Michel–Telegdi equation|Bargmann–Michel–Telegdi equation]] (1959) describing relativistic precession; [[Bargmann's limit]] of the maximum number of QM bound states of a potential (1952); the notion of '''Bargmann potentials'''<ref>V. Bargmann (1949). "On the Connection between Phase Shifts and Scattering Potential", Reviews of Modern Physics, 21(3), 488–493. doi:10.1103/revmodphys.21.488</ref> for the radial Schrödinger equations with bound states but no non-trivial scattering, which play a basic role in the theory of [[Soliton]]s, and the holomorphic representation in the [[Segal–Bargmann space]] (1961), including the [[Oscillator representation#Holomorphic Fock space|Bargmann kernel]].

Bargmann was elected a Fellow of the [[American Academy of Arts and Sciences]] in 1968.<ref name=AAAS>{{cite web|title=Book of Members, 1780-2010: Chapter B|url=http://www.amacad.org/publications/BookofMembers/ChapterB.pdf|publisher=American Academy of Arts and Sciences|access-date=May 17, 2011}}</ref> In 1978, he received the [[Wigner Medal]], together with Wigner himself, in the founding year of the prize. In 1979, Bargmann was elected to the US [[National Academy of Sciences]].<ref name=NAS>{{cite web|title=NAS Membership Directory|url=http://www.nasonline.org/member-directory/deceased-members/58006.html|publisher=National Academy of Sciences|access-date=March 22, 2020}}</ref> In 1988, he received the [[Max Planck Medal]] of the [[German Physical Society]].

He was also a talented pianist.

He died in [[Princeton, New Jersey|Princeton]] in 1989.

==References== {{Reflist}}

==External links== *[http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/bargmann-valentine.pdf National Academy of Sciences Biographical Memoir] by J R Klauder * [https://web.archive.org/web/20121016000334/http://www.princeton.edu/~mudd/finding_aids/mathoral/pmc02.htm The Princeton Mathematics Community in the 1930s, interview of Valentine Bargmann at Princeton University on 12 April 1984] * {{MathGenealogy|id=117922}} *[http://digilib.mpiwg-berlin.mpg.de/digitallibrary/servlet/Scaler?dw=425&dh=600&fn=permanent/einstein_exhibition/images/bargmann1& Photo from a website]

==Selected bibliography== *1934: "Über den Zusammenhang zwischen Semivektoren and Spinoren und die Reduktion der Diracgleichung für Semivektoren". ''Helv. Phys. Acta'' 7:57-82. *1936: "Zur Theorie des Wasserstoffatoms". ''Z. Phys.'' 99:576-82. *1937: "Über die durch Elektronenstrahlen in Kristallen angeregte Lichtemission". ''Helv. Phys. Acta'' 10:361-86. *1941: With A. Einstein and P. G. Bergmann. "On the five-dimensional representation of gravitation and electricity". In ''Theodore von Kármán Anniversary Volume'', pp.&nbsp;212–25,(Pasadena, California Institute of Technology). *1944: With A. Einstein. "Bivector fields". ''Ann. Math.'' 45:1-14. *1945: "On the glancing reflection of shock waves". ''Applied Mathematics Panel Report No. 108'' *1946: With D. Montgomery and J. von Neumann. "Solution of linear systems of high order". Report to the Bureau of Ordinance, U. S. Navy. *1947: "Irreducible unitary representations of the Lorentz group". ''Ann. Math.'' 48:568-640. *1948: With E. P. Wigner. "Group theoretical discussion of relativistic wave equations". ''Proc. Natl. Acad. Sci. U.S.A.'' 34:211-23. *1949: "Remarks on the determination of a central field of force from the elastic scattering phase shifts". ''Phys. Rev.'' 75:301-303. *&nbsp;"On the connection between phase shifts and scattering potential". ''Rev. Mod. Phys.'' 21:488-93. *1952: "On the number of bound states in a central field of force". ''Proc. Natl. Acad. Sci. U.S.A.'' 38:961-66. *1954: "On unitary ray representations of continuous groups". ''Ann. Math.'' 59:1-46. *1959: With L. Michel and V. Telegdi. "Precession of the polarization of particles moving in a homogeneous electromagnetic field". ''Phys. Rev. Lett.'' 2:435-36. *1960: "Relativity". In ''Theoretical Physics in the Twentieth Century (Pauli Memorial Volume)'', eds., M. Fierz and V. F. Weisskopf, pp.&nbsp;187–98. New York: Interscience Publishers. *&nbsp;With M. Moshinsky. "Group theory of harmonic oscillators. I. The collective modes". ''Nucl. Phys.'' 18:697-712. *1961: With M. Moshinsky. "Group theory of harmonic oscillators. II. The integrals of motion for the quadrupole-quadrupole interaction". ''Nucl. Phys.'' 23:177-99. *&nbsp;"On a Hilbert space of analytic functions and an associated integral transform. Part I." ''Commun. Pure Appl. Math.'' 14:187-214. *1962: "On the representations of the rotation group". ''Rev. Mod. Phys.'' 34:829-45. *1964: "Note on Wigner’s theorem on symmetry operations". ''J. Math. Phys.'' 5:862-68. *1967: "On a Hilbert space of analytic functions and an associated integral transform. Part II. A family of related function spaces application to distribution theory". ''Commun. Pure Appl. Math.'' 20:1-101. *1971: With P. Butera, L. Girardello, and J. R. Klauder. "On the completeness of the coherent states". ''Rep. Math. Phys.'' 2:221-28. *1972: "Notes on some integral inequalities". ''Helv. Phys. Acta'' 45:249-57. *1977: With I. T. Todorov. "Spaces of analytic functions on a complex cone as carriers for the symmetric tensor representations of SO(n)". ''J. Math. Phys.'' 18:1141-48. *1979: "Erinnerungen eines Assistanten Einsteins". Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich, Jahrgang 124, Heft 1, pp.&nbsp;39–44. Zürich: Druck und Verlag Orell Fussli Graphische Betriebe AG.

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{{DEFAULTSORT:Bargmann, Valentine}} [[Category:1908 births]] [[Category:1989 deaths]] [[Category:20th-century American mathematicians]] [[Category:20th-century German mathematicians]] [[Category:20th-century American physicists]] [[Category:Fellows of the American Academy of Arts and Sciences]] [[Category:Members of the United States National Academy of Sciences]] [[Category:20th-century German physicists]] [[Category:Jewish emigrants from Nazi Germany to the United States]] [[Category:Emigrants from Nazi Germany to the United States]] [[Category:Institute for Advanced Study visiting scholars]] [[Category:Mathematical physicists]] [[Category:University of Zurich alumni]] [[Category:Jewish American physicists]] [[Category:Winners of the Max Planck Medal]] [[Category:Jewish German physicists]]