Herbert Bernard Callen (July 1, 1919 – May 22, 1993) was an American physicist specializing in thermodynamics and statistical mechanics. He is considered one of the founders of the modern theory of irreversible thermodynamics,
and is the author of the classic textbook ''
Thermodynamics and an Introduction to Thermostatistics'', published in two editions.
During World War II, his services were invoked in the theoretical division of the
Manhattan Project.
Life and work
A native of
Philadelphia
Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
, Herbert Callen received his
Bachelor of Science
A Bachelor of Science (BS, BSc, B.S., B.Sc., SB, or ScB; from the Latin ') is a bachelor's degree that is awarded for programs that generally last three to five years.
The first university to admit a student to the degree of Bachelor of Scienc ...
degree from
Temple University
Temple University (Temple or TU) is a public university, public Commonwealth System of Higher Education, state-related research university in Philadelphia, Philadelphia, Pennsylvania, United States. It was founded in 1884 by the Baptist ministe ...
. His graduate studies were interrupted by the
Manhattan Project. He also worked on a U.S. Navy project concerning guided missiles (Project Bumblebee) at Princeton University in 1945.
Callen subsequently completed his
PhD in physics at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
(MIT) in 1947. He was supervised by the physicist
László Tisza. His doctoral dissertation concerns the Kelvin thermoelectric and thermomagnetic relations, and
Onsager's
reciprocal relations;
it was titled ''On the Theory of Irreversible Processes''. Upon receiving his degree, Callen spent a year at the MIT Laboratory for Insulation Research and developed his theory of electrical breakdown for insulators.
In 1948, Callen joined the faculty of the department of physics at the
University of Pennsylvania
The University of Pennsylvania (Penn or UPenn) is a Private university, private Ivy League research university in Philadelphia, Pennsylvania, United States. One of nine colonial colleges, it was chartered in 1755 through the efforts of f ...
and became a professor in 1956.
Specialists consider his most lasting contribution to physics to be the paper co-written with
Theodore A. Welton presenting a proof of the
fluctuation-dissipation theorem, an extremely general result describing how a system's response to perturbations relates to its behavior at equilibrium.
This crucial result became the basis for the statistical theory of
irreversible processes and explains how fluctuations dissipate energy into heat in general
and the phenomenon of
Nyquist noise in particular.
Callen then pioneered the thermodynamic
Green's functions for magnetism. With his students, he studied many-body problems involving
spin operators. This led to the discovery of some useful methods of approximations.
The first edition of his classic text ''Thermodynamics and an Introduction to Thermostatistics'' was published in 1960.
In it, he presents a rigorous axiomatic treatment of thermodynamics in which the state functions are the fundamental entities and the processes are their differentials.
The postulates concern the existence of thermal equilibrium, and the properties of entropy. From them, he derives the fundamentals of thermodynamics, found in the first eight chapters.
The much revised second edition, published in 1985, became a highly cited reference in the literature
and an enduring textbook.
He was a successful teacher, noted for his ability to explain complicated phenomena in simple terms. He played a key role in the recruitment of promising solid-state physicists to the University of Pennsylvania in the late 1950s and continued to be active in the university's academic affairs till his retirement in 1985.
He was the recipient of a
Guggenheim Fellowship
Guggenheim Fellowships are Grant (money), grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation, endowed by the late Simon Guggenheim, Simon and Olga Hirsh Guggenheim. These awards are bestowed upon indiv ...
for the academic year 1972–1973. In 1984, Callen received the
Elliott Cresson Medal from the
Franklin Institute. He retired in 1985.
He was made a member of the
National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...
in 1990.
After battling
Alzheimer's disease
Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...
for eleven years, Callen died in the Philadelphia suburb of
Merion in 1993. He was 73 years old. He was survived by his wife, Sara Smith, and their two children, Jed and Jill.
Commenting on his own approach to science, Callen noted the importance of "inspired insight guided by faith in the simplicity of nature."
See also
*
List of textbooks in thermodynamics and statistical mechanics
*
Richard Chase Tolman
*
Constantin Carathéodory, who also sought an axiomatic formulation of thermodynamics
References
External links
*Callen, Herbert B, and Theodore A Welton. �
Irreversibility and Generalized Noise” ''Physical Review'', vol. 83, no. 1, 1951, pp. 34–40.
{{DEFAULTSORT:Callen, Herbert
1919 births
1993 deaths
20th-century American physicists
20th-century American writers
Massachusetts Institute of Technology School of Science alumni
Scientists from Philadelphia
Temple University alumni
Thermodynamicists
University of Pennsylvania faculty
Manhattan Project people
Members of the United States National Academy of Sciences
Deaths from dementia in Pennsylvania
Deaths from Alzheimer's disease in Pennsylvania