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Rolf William Landauer (February 4, 1927 – April 28, 1999) was a German-American physicist who made important contributions in diverse areas of the thermodynamics of information processing, condensed matter physics, and the conductivity of disordered media.[1] In 1961 he discovered Landauer's principle, that in any logically irreversible operation that manipulates information, such as erasing a bit of memory, entropy increases and an associated amount of energy is dissipated as heat.[1] This principle is relevant to reversible computing, quantum information and quantum computing. He also is responsible for the Landauer formula relating the electrical resistance of a conductor to its scattering properties. He won the Stuart Ballantine Medal of the Franklin Institute, the Oliver Buckley Prize of the American Physical Society and the IEEE Edison Medal, among many other honors.[1]


Landauer was born on February 4, 1927, in Stuttgart, Germany. He emigrated to the United States in 1938 to escape Nazi persecution of Jews, graduated in 1943 from Stuyvesant High School, one of New York City's mathematics and science magnet schools, and obtained his undergraduate degree from Harvard in 1945. Following service in the US Navy as an Electrician's Mate, he earned his Ph.D. from Harvard in 1950.[2]

He first worked for two years at NASA, then known as the National Advisory Committee for Aeronautics, and at the age of 25 began a career in semiconductors at IBM. As part of the two-man team responsible for managing IBM's Research Division in the mid-1960s, he was involved in a number of programs, including the company's work on semiconductor lasers. In 1969, he was appointed an IBM Fellow.

Much of his research after 1969 related to the kinetics of small structures. He showed that in systems with two or more competing states of local stability, their likelihood depends on noise all along the path connecting them. In electron transport theory, he is particularly associated with the idea, taken from circuit theory, that electric flow can be considered a consequence of current sources as well as applied fields. He was also a pioneer in the area of information handling. His principles have been applied to computers and to the measurement process and are the basis for Landauer's own demonstration that communication, in principle, can not avoid a small use of energy.

Rolf William Landauer died on 28 April 1999 at his home in Briarcliff Manor from brain cancer.[2][3]

Awards and honors

The range of his work has been recognized in special issues of two journals, 10 years apart: the IBM Journal of Research and Development (January 1988) and Superlattices and Microstructures (March/April 1998).


  1. ^ a b c Bennett, Charles H.; Fowler, Alan B. (2009). "Rolf W. Landauer (1927 - 1999) A biographical memoir" (PDF). Biographical Memoirs v. 91 (2009) (PDF)|format= requires |url= (help). National Academy of Sciences. doi:10.17226/12776. ISBN 978-0-309-14560-2. 
  2. ^ a b Johnson, George (April 30, 1999). "Rolf Landauer, Pioneer in Computer Theory, Dies at 72". The New York Times. Rolf W. Landauer, who helped solidify the slippery concept of information and bring it firmly into the mainstream of physics, died on Wednesday at his home in Briarcliff Manor, N.Y. He was 72. He died of brain cancer, his family said. 
  3. ^ Fowler, Alan; Bennett, Charles H.; Keller, Seymour P.; Imry, Yosef (October 1999). "Obituary: Rolf William Landauer". Physics Today. 52 (10): 104–105. Bibcode:1999PhT....52j.104F. doi:10.1063/1.882874.  CS1 maint: Multiple names: authors list (link)

Further reading

  • Perry, R. T. (2004). The temple of quantum computing. p. 26 – 27. Retrieved 11 January 2005.