Rudolf Haag facts for kids

Quick facts for kids Rudolf Haag
Rudolf Haag in 1992
Born	(1922-08-17)17 August 1922 Tübingen, Germany
Died	5 January 2016(2016-01-05) (aged 93) Neuhaus (Schliersee), Germany
Nationality	German
Alma mater	University of Stuttgart University of Munich
Known for	Haag–Kastler axioms Haag–Łopuszański–Sohnius theorem Haag's theorem Haag–Ruelle scattering theory
Awards	Max Planck medal (1970)   Henri Poincaré Prize (1997)
Scientific career
Fields	Physics
Institutions	University of Munich Max Planck Institute for Physics Princeton University University of Marseille University of Illinois Urbana-Champaign University of Hamburg
Thesis	Die korrespondenzmäßige Methode in der Theorie der Elementarteilchen (1951)
Doctoral advisor	Fritz Bopp
Doctoral students	Huzihiro Araki Detlev Buchholz Klaus Fredenhagen Bert Schroer

Rudolf Haag (born August 17, 1922 – died January 5, 2016) was a German physicist. He focused on the basic ideas of quantum field theory. This is a field of physics that studies tiny particles and forces.

Haag helped create the modern way of understanding quantum field theory. He looked at how things work based on the idea of locality. This means that things only affect their immediate surroundings. He also made big steps in quantum statistical mechanics. This area combines quantum physics with how large groups of particles behave.

Early Life and Education

Rudolf Haag was born in Tübingen, Germany, on August 17, 1922. His family was well-educated. His mother, Anna Haag, was a writer and politician. His father, Albert Haag, taught mathematics at a high school.

After finishing high school in 1939, Rudolf visited his sister in London. This was just before World War II started. He was held in a camp for German civilians in Manitoba, Canada. During this time, he taught himself physics and mathematics. He studied in his free time after his daily work.

After the war, Haag went back to Germany. In 1946, he started studying at the Technical University of Stuttgart. He became a physicist in 1948. In 1951, he earned his PhD from the University of Munich. His advisor was Fritz Bopp. Haag then worked as Bopp's assistant until 1956.

Professional Journey

In 1953, Rudolf Haag joined a research group at CERN in Copenhagen. This group was led by Niels Bohr, a famous physicist. After a year, Haag returned to Munich. He completed his "habilitation" in 1954. This is a special qualification needed to teach at German universities.

From 1956 to 1957, he worked with Werner Heisenberg at the Max Planck Institute for Physics. Heisenberg was another very important physicist.

Haag then worked as a visiting professor at Princeton University from 1957 to 1959. He also worked at the University of Marseille from 1959 to 1960. In 1960, he became a physics professor at the University of Illinois Urbana-Champaign.

In 1965, Haag and Res Jost started a science journal. It was called Communications in Mathematical Physics. Haag was the first editor-in-chief until 1973. In 1966, he became a professor at the University of Hamburg. He stayed there until he retired in 1987. After retiring, he studied the idea of a "quantum physical event."

Personal Life

Rudolf Haag loved music from a young age. He first learned the violin. Later, he preferred the piano and played it almost every day. In 1948, Haag married Käthe Fues. They had four children: Albert, Friedrich, Elisabeth, and Ulrich.

After he retired, he moved with his second wife, Barbara Klie, to Schliersee. This is a quiet village in the mountains of Bavaria. Rudolf Haag passed away on January 5, 2016, in Fischhausen-Neuhaus, Germany.

Key Scientific Contributions

Rudolf Haag made big contributions to quantum field theory. He helped develop Haag's theorem. This theorem shows that a certain way of describing particles in quantum mechanics doesn't work in quantum field theory. This meant a new way was needed to describe how particles scatter or bounce off each other.

Haag then created what is called Haag–Ruelle scattering theory. While working on this, he realized that the old idea of a fixed link between fields and particles was not quite right. He thought that understanding particles should be based on Albert Einstein's idea of locality. This idea connects actions to specific areas of space and time.

These ideas led to the Haag–Kastler axioms. These are a set of rules for understanding local "observables" in quantum field theories. Observables are things we can measure. This approach uses ideas from operator algebras. It is also known as algebraic quantum field theory or local quantum physics.

This new way of thinking helped physicists understand the basic properties of theories in four-dimensional Minkowski spacetime. This is the space-time we live in. Haag, with Sergio Doplicher and John E. Roberts, studied how different types of particles behave. They showed that particles have properties like charge and follow certain rules, like having antiparticles.

Haag also worked on quantum statistical mechanics. With Nicolaas M. Hugenholtz and Marius Winnink, he helped describe states of thermal equilibrium. This is when a system is stable and not changing. This work led to the Tomita–Takesaki theory. This theory is important for understanding the structure of quantum systems.

With Klaus Fredenhagen, Heide Narnhofer, and Ulrich Stein, Haag also helped understand the Unruh effect and Hawking radiation. These are interesting ideas about how black holes and acceleration affect particles.

Haag was careful about new, untested ideas in physics. But he did explore some of them. One famous contribution is the Haag–Łopuszański–Sohnius theorem. This theorem helps classify different types of Supersymmetry. Supersymmetry is a theory that suggests every particle has a "superpartner."

Awards and Recognition

Rudolf Haag received several important awards for his work. In 1970, he was given the Max Planck Medal. This award is for great achievements in theoretical physics. In 1997, he won the Henri Poincaré Prize. This was for his basic contributions to quantum field theory.

He was also a member of several important science academies. These included the German National Academy of Sciences Leopoldina and the Göttingen Academy of Sciences and Humanities. He was also a corresponding member of the Bavarian Academy of Sciences and the Austrian Academy of Sciences.

See also

In Spanish: Rudolf Haag para niños