Heinz-Dieter Zeh (; 8 May 1932 – 15 April 2018) was

theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict natural phenomena. This is in contrast to experimental physics, which uses experi ...

and

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...

emeritus ''Emeritus/Emerita'' () is an honorary title granted to someone who retires from a position of distinction, most commonly an academic faculty position, but is allowed to continue using the previous title, as in "professor emeritus". In some c ...

of the

University of Heidelberg Heidelberg University, officially the Ruprecht Karl University of Heidelberg (; ), is a public university, public research university in Heidelberg, Baden-Württemberg, Germany. Founded in 1386 on instruction of Pope Urban VI, Heidelberg is List ...

. He is known for formalizing the theory of

quantum decoherence Quantum decoherence is the loss of quantum coherence. It involves generally a loss of information of a system to its environment. Quantum decoherence has been studied to understand how quantum systems convert to systems that can be expla ...

Education and career

H. Dieter Zeh was born in

Braunschweig Braunschweig () or Brunswick ( ; from Low German , local dialect: ) is a List of cities and towns in Germany, city in Lower Saxony, Germany, north of the Harz Mountains at the farthest navigable point of the river Oker, which connects it to the ...

and studied physics at the

Technical University of Braunschweig TU Braunschweig (, unofficially ''University of Braunschweig – Institute of Technology'') is the oldest ' (comparable to an institute of technology in the American system) in Germany. It was founded in 1745 as Collegium Carolinum and is a membe ...

and nuclear physics at the

under

J. Hans D. Jensen Johannes Hans Daniel Jensen (; 25 June 1907 – 11 February 1973) was a German nuclear physicist. During World War II, he worked on the German nuclear energy project, known as the Uranium Club, where he contributed to the separation of uranium ...

. At Heidelberg, he also investigated

alpha particle Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay but may also be produce ...

formation in nuclei with and Zeh investigated the topic for his PhD thesis under Mang. Between 1964 and 1965, Zeh was a research assistant at

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

and in 1965 and between 1967 and 1968 at the

University of California, San Diego The University of California, San Diego (UC San Diego in communications material, formerly and colloquially UCSD) is a public university, public Land-grant university, land-grant research university in San Diego, California, United States. Es ...

. He later became a professor in Heidelberg.

Research

Zeh is known for his work on

decoherence Quantum decoherence is the loss of quantum coherence. It involves generally a loss of information of a system to its environment. Quantum decoherence has been studied to understand how quantum systems convert to systems that can be expla ...

, formally described in his 1970 seminal paper. He showed that the environment plays a central role in recovering the

classical limit The classical limit or correspondence limit is the ability of a physical theory to approximate or "recover" classical mechanics when considered over special values of its parameters. The classical limit is used with physical theories that predict n ...

from quantum mechanics. In his paper he discussed applications, like explaining the emergence of

chirality Chirality () is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable fro ...

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

molecules. In 1973, with Olaf Kübler, Zeh explained using a reduced

density matrix In quantum mechanics, a density matrix (or density operator) is a matrix used in calculating the probabilities of the outcomes of measurements performed on physical systems. It is a generalization of the state vectors or wavefunctions: while th ...

why

coherent state In physics, specifically in quantum mechanics, a coherent state is the specific quantum state of the quantum harmonic oscillator, often described as a state that has dynamics most closely resembling the oscillatory behavior of a classical harmo ...

are the most classical states, and why

quantum superposition Quantum superposition is a fundamental principle of quantum mechanics that states that linear combinations of solutions to the Schrödinger equation are also solutions of the Schrödinger equation. This follows from the fact that the Schrödi ...

can never be observed. Zeh's works provided a solution to the preferred basis problem in quantum mechanics. The term decoherence did not appear until 1989. The first experimental demonstrations of Zeh's work were given about 1996 by

Serge Haroche Serge Haroche (born 11 September 1944) is a French physicist who was awarded the 2012 Nobel Prize for Physics jointly with David J. Wineland for "ground-breaking experimental methods that enable measuring and manipulation of individual quantum sy ...

in France and

David J. Wineland David Jeffery Wineland (born February 24, 1944) is an American physicist at the Physical Measurement Laboratory of the National Institute of Standards and Technology (NIST). His most notable contributions include the laser cooling of trapped ...

in United States, who also earned the 2012

Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...

. Zeh's 1970 work was also one of the founding papers of the

many-minds interpretation The many-minds interpretation of quantum mechanics extends the many-worlds interpretation by proposing that the distinction between worlds should be made at the level of the mind of an individual observer. The concept was first introduced in 1970 b ...

quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

. Zeh also dedicated a large part of his work to

quantum gravity Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics. It deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the v ...

. In 1986, he argued that gravity assumes classical properties due to environmental degrees of freedom, such as the presence of

gravitational waves Gravitational waves are oscillations of the gravitational field that travel through space at the speed of light; they are generated by the relative motion of gravitating masses. They were proposed by Oliver Heaviside in 1893 and then later by H ...

Bibliography

*''The Problem Of Conscious Observation In Quantum Mechanical Description'' (June, 2000). *''The Physical Basis of the Direction of Time'', 2001, *''Decoherence and the Appearance of a Classical World in Quantum Theory'', 2003, (with Erich Joos, Claus Kiefer, Domenico Giulini, Joachim Kupsch, Ion-Olimpiu Stamatescu) * "On the interpretation of measurement in quantum theory", 1970, Foundations of Physics, Volume 1, Issue 1, pp. 69–76

References

External links

Zeh's old homepageObituary for H. Dieter Zeh
1932 births 2018 deaths 20th-century German physicists German quantum physicists Science teachers German science writers Scientists from Braunschweig German theoretical physicists German male non-fiction writers Academic staff of Heidelberg University Heidelberg University alumni TU Braunschweig alumni {{Germany-physicist-stub

Education and career

Research

Bibliography

See also

References

External links