Felix Bloch

This article is about the Swiss physicist. For the man accused of espionage, seeFelix Bloch (diplomatic officer).

Felix Bloch
Born	(1905-10-23)23 October 1905 Zürich,Switzerland
Died	10 September 1983(1983-09-10)(aged 77) Zürich, Switzerland
Nationality	Swiss
Citizenship	Swiss American
Alma mater	ETH Zürich University of Leipzig
Known for	NMR spectroscopy Magnon Spin wave Tight binding Inverse cyclotron converter Bloch equations Bloch oscillation Bloch wave Bloch wall Bloch's theorem Bloch sphere Bloch spectrum BlochT3/2law Bloch–Grüneisen temperature Bloch–Nordsieck theorem Bloch–Siegert shift Bethe–Bloch formula
Awards	Nobel Prize for Physics(1952) Fritz London Memorial Lecture(1959) Guggenheim Fellowship(1959) Pour le Mérite for Sciences and Arts(1979)
Scientific career
Fields	Physics
Institutions	Stanford University University of California, Berkeley
Doctoral advisor	Werner Heisenberg
Doctoral students	Carson D. Jeffries

Felix Bloch(23 October 1905 – 10 September 1983) was a Swiss-Americanphysicistand Nobel physics laureate who worked mainly in the U.S.He andEdward Mills Purcellwere awarded the 1952Nobel Prize for Physicsfor "their development of new ways and methods for nuclear magnetic precision measurements."In 1954–1955, he served for one year as the first director-general ofCERN.Felix Bloch made fundamental theoretical contributions to the understanding offerromagnetismand electron behavior incrystal lattices.He is also considered one of the developers ofnuclear magnetic resonance.

Biography

Felix Bloch in the lab, 1950s

Early life, education, and family

Bloch was born inZürich,Switzerland toJewishparents Gustav and Agnes Bloch. Gustav Bloch, his father, was financially unable to attend University and worked as a wholesale grain dealer in Zürich.Gustav moved to Zürich fromMoraviain 1890 to become a Swiss citizen. Their first child was a girl born in 1902 while Felix was born three years later.

Bloch entered public elementary school at the age of six and is said to have been teased, in part because he "spoke Swiss German with a somewhat different accent than most members of the class".He received support from his older sister during much of this time, but she died at the age of twelve, devastating Felix, who is said to have lived a "depressed and isolated life" in the following years.Bloch learned to play the piano by the age of eight and was drawn to arithmetic for its "clarity and beauty".Bloch graduated from elementary school at twelve and enrolled in the Cantonal Gymnasium in Zürich for secondary school in 1918. He was placed on a six-year curriculum here to prepare him for University. He continued his curriculum through 1924, even through his study of engineering and physics in other schools, though it was limited to mathematics and languages after the first three years. After these first three years at the Gymnasium, at age fifteen Bloch began to study at theEidgenössische Technische Hochschule(ETHZ), also in Zürich. Although he initially studied engineering he soon changed to physics. During this time he attended lectures and seminars given byPeter DebyeandHermann Weylat ETH Zürich andErwin Schrödingerat the neighboringUniversity of Zürich.A fellow student in these seminars wasJohn von Neumann.

Bloch graduated in 1927, and was encouraged by Debye to go toLeipzigto study withWerner Heisenberg.Bloch became Heisenberg's first graduate student, and gained his doctorate in 1928.His doctoral thesis established thequantum theory of solids,using waves to describeelectronsin periodic lattices.

On March 14, 1940, Bloch married Lore Clara Misch (1911–1996), a fellow physicist working onX-ray crystallography,whom he had met at anAmerican Physical Societymeeting.They had four children, twins George Jacob Bloch and Daniel Arthur Bloch (born January 15, 1941), son Frank Samuel Bloch (born January 16, 1945), and daughter Ruth Hedy Bloch (born September 15, 1949).

Career

Bloch remained in European academia, working on superconductivity withWolfgang Pauliin Zürich; withHans KramersandAdriaan Fokkerin Holland; with Heisenberg onferromagnetism,where he developed a description of boundaries between magnetic domains, now known as "Bloch walls",and theoretically proposed a concept ofspin waves,excitations of magnetic structure; withNiels BohrinCopenhagen,where he worked on a theoretical description of the stopping of charged particles traveling through matter; and withEnrico Fermiin Rome.In 1932, Bloch returned to Leipzig to assume a position as "Privatdozent" (lecturer).In 1933, immediately afterHitlercame to power, he left Germany because he was Jewish, returning to Zürich, before traveling to Paris to lecture at theInstitut Henri Poincaré.

In 1934, the chairman ofStanfordPhysics invited Bloch to join the faculty.Bloch accepted the offer and emigrated to the United States. In the fall of 1938, Bloch began working with the 37 inch cyclotron at theUniversity of California, Berkeleyto determine the magnetic moment of the neutron. Bloch went on to become the first professor for theoretical physics at Stanford. In 1939, he became anaturalized citizenof the United States.

DuringWWII,Bloch briefly worked on theatomic bomb projectatLos Alamos.Disliking the military atmosphere of the laboratory and uninterested in the theoretical work there, Bloch left to join theradarproject atHarvard University.

After the war, he concentrated on investigations into nuclear induction andnuclear magnetic resonance,which are the underlying principles ofMRI.In 1946 he proposed theBloch equationswhich determine the time evolution of nuclear magnetization. He was elected to the United StatesNational Academy of Sciencesin 1948.Along withEdward Purcell,Bloch was awarded the 1952Nobel Prize in Physicsfor his work on nuclear magnetic induction.

WhenCERNwas being set up in the early 1950s, its founders were searching for someone of stature and international prestige to head the fledgling international laboratory, and in 1954 Professor Bloch became CERN's first director-general,at the time when construction was getting under way on the presentMeyrinsite and plans for the first machines were being drawn up. After leaving CERN, he returned toStanford University,where he in 1961 was madeMax SteinProfessor of Physics.

In 1964, he was elected a foreign member of theRoyal Netherlands Academy of Arts and Sciences.He was also a member of theAmerican Academy of Arts and Sciencesand theAmerican Philosophical Society.

Bloch died in Zürich in 1983.

See also

• List of Jewish Nobel laureates
• List of things named after Felix Bloch

References

• "Nobel Prize for Physics, 1952".Nature.170(4335): 911–912. 1952.Bibcode:1952Natur.170R.911..doi:10.1038/170911b0.S2CID4205574.
• "Deputy Director-General: Prof. E. Amaldi".Nature.174(4434): 774–775. 1954.Bibcode:1954Natur.174R.774..doi:10.1038/174774c0.S2CID4263821.
• McGraw-Hill Modern Men of Science.Vol. 1.McGraw-Hill.1966. pp. 45–46.ISBN978-0-07-045217-6.
• National Cyclopaedia of American Biography.Vol. 61.James T. White & Co.1984. pp. 310–312.ISBN0-88371-040-4.

Further reading

• Bloch, F.; Staub, H."Fission Spectrum", Los Alamos National Laboratory (LANL) (through predecessor agency Los Alamos Scientific Lab), United States Department of Energy (through predecessor agency the US Atomic Energy Commission), (August 18, 1943).

External links

• Media related toFelix Blochat Wikimedia Commons

• Felix Blochon Nobelprize.org
• Oral History interview transcript with Felix Bloch on 14 May 1964, American Institute of Physics, Niels Bohr Library and Archives- interview conducted byThomas S. KuhninPalo Alto, California
• Oral History interview transcript with Felix Bloch on 15 August 1968, American Institute of Physics, Niels Bohr Library and Archives- interview conducted by Charles Weiner atStanford University
• Oral History interview transcript with Felix Bloch 15 December 1981, American Institute of Physics, Niels Bohr Library and Archives- interview conducted byLillian HoddesonatStanford University
• Felix Bloch Papers, 1931–1987(33 linear ft.) are housed in theDepartment of Special Collections and University ArchivesatStanford University Libraries
• National Academy of Sciences Biographical Memoir
• Felix Bloch Papers