Harald Fritzsch (10 February 1943 in
Zwickau, Germany – 16 August 2022 in
München) was a German theoretical
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 ...
known for his contributions to the theory of
quarks, the development of
Quantum Chromodynamics
In theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of ...
and the grand unification of the
standard model of particle physics.
Education and career
After completing his education in Zwickau 1961, he became a soldier in the
Nationale Volksarmee of the
GDR. He studied Physics in
Leipzig
Leipzig (, ; ; Upper Saxon: ; ) is the most populous city in the States of Germany, German state of Saxony. The city has a population of 628,718 inhabitants as of 2023. It is the List of cities in Germany by population, eighth-largest city in Ge ...
from 1963 to 1968, where he completed his ''
Diplom'' under Hans-Juergen Treder. After fleeing to
West Germany
West Germany was the common English name for the Federal Republic of Germany (FRG) from its formation on 23 May 1949 until German reunification, its reunification with East Germany on 3 October 1990. It is sometimes known as the Bonn Republi ...
, Fritzsch continued his studies in
Munich
Munich is the capital and most populous city of Bavaria, Germany. As of 30 November 2024, its population was 1,604,384, making it the third-largest city in Germany after Berlin and Hamburg. Munich is the largest city in Germany that is no ...
where he finished his
Ph.D. under the supervision of
Heinrich Mitter.
In 1970 Fritzsch visited the
Aspen Center for Physics, where he met
Murray Gell-Mann
Murray Gell-Mann (; September 15, 1929 – May 24, 2019) was an American theoretical physicist who played a preeminent role in the development of the theory of elementary particles. Gell-Mann introduced the concept of quarks as the funda ...
. They started a collaboration, first in Aspen, later at the California Institute of Technology. In 1971 they introduced the concept of the
colour charge quantum number which allowed them in collaboration with
William A. Bardeen to explain the decay rate of
pion
In particle physics, a pion (, ) or pi meson, denoted with the Greek alphabet, Greek letter pi (letter), pi (), is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the ...
s. In the fall of 1971 Fritzsch and Gell-Mann moved to Geneva in Switzerland, where they worked together at
CERN
The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Gene ...
. They proposed a
gauge theory
In physics, a gauge theory is a type of field theory in which the Lagrangian, and hence the dynamics of the system itself, does not change under local transformations according to certain smooth families of operations (Lie groups). Formally, t ...
for the
strong interaction
In nuclear physics and particle physics, the strong interaction, also called the strong force or strong nuclear force, is one of the four known fundamental interaction, fundamental interactions. It confines Quark, quarks into proton, protons, n ...
, which now is called Quantum Chromodynamics. In September 1972 they moved back to Caltech. In 1975 Fritzsch published a paper together with
Peter Minkowski in which they proposed the symmetry group
SO(10) as the symmetry of the
grand unified theory which has become a standard theory. In 1976 Fritzsch moved to CERN. After working for one year at the University of Wuppertal and the University of Bern, Fritzsch was appointed Professor at the
Ludwig Maximilian University of Munich
The Ludwig Maximilian University of Munich (simply University of Munich, LMU or LMU Munich; ) is a public university, public research university in Munich, Bavaria, Germany. Originally established as the University of Ingolstadt in 1472 by Duke ...
in 1980.
Fritzsch worked also on "composite models" of leptons and quarks, mass matrices of quarks and leptons, weak decays of heavy quarks, cosmology and the fundamental constants of physics. He retired in 2008 and died 16 August 2022 in
München.
In 1971 Fritzsch married Brigitte Goralski. They had two children.
Works
* ''Quarks: The Stuff of Matter'' (1989, )
* ''The Creation of Matter: The Universe from Beginning to End'' (1984, )
''An Equation That Changed the World: Newton, Einstein, and the Theory of Relativity''(1997, )
''The Curvature of Spacetime: Newton, Einstein, and Gravitation''(2005, )
* ''Elementary Particles: Building Blocks of Matter'' (2005, )
* ''Escape From Leipzig'' (2008, )
''The Fundamental Constants: A Mystery of Physics''(2009, (paperback)); hbk.
(2011, )
''Microcosmos: The World of Elementary Particles: Fictional Discussions between Einstein, Newton, and Gell-Mann''(2013, )
* ''50 Years of Quarks'' (with Murray Gell-Mann, 2015, )
References
{{DEFAULTSORT:Fritzsch, Harald
1943 births
2022 deaths
20th-century German physicists
German theoretical physicists
Academic staff of the Ludwig Maximilian University of Munich
People associated with CERN
21st-century German physicists
Aspen Center for Physics people
People from Zwickau