Rolf William Landauer (February 4, 1927 – April 27, 1999) was a

German-American German Americans (, ) are Americans who have full or partial German ancestry. According to the United States Census Bureau's figures from 2022, German Americans make up roughly 41 million people in the US, which is approximately 12% of the pop ...

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 ...

who made important contributions in diverse areas of the

thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed b ...

of information processing, condensed matter physics, and the conductivity of disordered media. Born in Germany, he emigrated to the U.S. in 1938, obtained a Ph.D. in physics from

Harvard Harvard University is a private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher lear ...

in 1950, and then spent most of his career at

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

. In 1961 he discovered

Landauer's principle Landauer's principle is a physical principle pertaining to a lower theoretical limit of energy consumption of computation. It holds that an irreversible change in information stored in a computer, such as merging two computational paths, dissipa ...

, that in any logically irreversible operation that manipulates

information Information is an Abstraction, abstract concept that refers to something which has the power Communication, to inform. At the most fundamental level, it pertains to the Interpretation (philosophy), interpretation (perhaps Interpretation (log ...

, such as erasing a bit of memory,

entropy Entropy is a scientific concept, most commonly associated with states of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the micros ...

increases and an associated amount of

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

is dissipated as

heat In thermodynamics, heat is energy in transfer between a thermodynamic system and its surroundings by such mechanisms as thermal conduction, electromagnetic radiation, and friction, which are microscopic in nature, involving sub-atomic, ato ...

. This principle is relevant to

reversible computing Reversible computing is any model of computation where every step of the process is time-reversible. This means that, given the output of a computation, it's possible to perfectly reconstruct the input. In systems that progress deterministica ...

quantum information Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both t ...

and

quantum computing A quantum computer is a computer that exploits quantum mechanical phenomena. On small scales, physical matter exhibits properties of wave-particle duality, both particles and waves, and quantum computing takes advantage of this behavior using s ...

. He also is responsible for the Landauer formula relating the

electrical resistance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual paral ...

of a conductor to its scattering properties. He won the

Stuart Ballantine Medal {{Refimprove, date=February 2018 The Stuart Ballantine Medal was a science and engineering award presented by the Franklin Institute, of Philadelphia, Pennsylvania, USA. It was named after the US inventor Stuart Ballantine. Laureates *1947 - Ge ...

of the

Franklin Institute The Franklin Institute is a science museum and a center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin ...

, the Oliver Buckley Prize of the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...

and the

IEEE Edison Medal The IEEE Edison Medal is presented by the Institute of Electrical and Electronics Engineers (IEEE) "for a career of meritorious achievement in electrical science, electrical engineering, or the electrical arts." It is the oldest medal in this fi ...

, among many other honors.

Biography

Landauer was born on February 4, 1927, in

Stuttgart Stuttgart (; ; Swabian German, Swabian: ; Alemannic German, Alemannic: ; Italian language, Italian: ; ) is the capital city, capital and List of cities in Baden-Württemberg by population, largest city of the States of Germany, German state of ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

. He

emigrated Emigration is the act of leaving a resident country or place of residence with the intent to settle elsewhere (to permanently leave a country). Conversely, immigration describes the movement of people into one country from another (to permanentl ...

to the United States in 1938 to escape

Nazi Nazism (), formally named National Socialism (NS; , ), is the far-right politics, far-right Totalitarianism, totalitarian socio-political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in Germany. During H ...

persecution of

Jew Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, religion, and community are highly inte ...

s, graduated in 1943 from

Stuyvesant High School Stuyvesant High School ( ) is a co-ed, State school, public, college-preparatory, Specialized high schools in New York City, specialized high school in Manhattan, New York City. The school, commonly called "Stuy" ( ) by its students, faculty, a ...

, one of

New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...

's mathematics and science

magnet schools In education in the United States, the U.S. education system, magnet schools are State school, public schools with Specialized school, specialized Course (education), courses or Curriculum, curricula. Normally, a student will attend an elementary ...

, and obtained his undergraduate degree from

in 1945. Following service in the

US Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

as an Electrician's Mate, he earned his Ph.D. from Harvard in 1950. His advisor was initially

Léon Brillouin Léon Nicolas Brillouin (; August 7, 1889 – October 4, 1969) was a French physicist. He made contributions to quantum mechanics, radio wave propagation in the atmosphere, solid-state physics, and information theory. Early life Brilloui ...

but he finished the thesis under the supervision of Wendell H. Furry. He first worked for two years at

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

, then known as the National Advisory Committee for Aeronautics, at its

Glenn Research Center NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park, Ohio, Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a s ...

, then known as the Lewis Research Center, in Cleveland. At the age of 25, he began a career in semiconductors at

IBM Research IBM Research is the research and development division for IBM, an American Multinational corporation, multinational information technology company. IBM Research is headquartered at the Thomas J. Watson Research Center in Yorktown Heights, New York ...

. 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 An IBM Fellow is a position at IBM appointed by the CEO. Typically only four to nine (eleven in 2014) IBM Fellows are appointed each year, in May or June. Fellow is the highest honor a scientist, engineer, or programmer at IBM can achieve. Over ...

. 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 be accomplished with arbitrarily little dissipation of energy. Rolf William Landauer died on 27 April 1999 at his home in Briarcliff Manor from brain cancer.

Awards and honors

*Fellow,

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...

*Member,

National Academy of Engineering The National Academy of Engineering (NAE) is an American Nonprofit organization, nonprofit, NGO, non-governmental organization. It is part of the National Academies of Sciences, Engineering, and Medicine (NASEM), along with the National Academ ...

*Member,

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 ...

*Member,

European Academy of Sciences and Arts The European Academy of Sciences and Arts (EASA, ) is a transnational and interdisciplinary network, connecting about 2,000 recommended scientists and artists worldwide, including 38 Nobel Prize laureates. The European Academy of Sciences and ...

*Fellow,

American Academy of Arts and Sciences The American Academy of Arts and Sciences (The Academy) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other ...

*Honorary doctorate, Technion in

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

*1991 Scott Lecturer at the

Cavendish Laboratory The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is named ...

Cambridge University The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

*1992

of the

*Centennial Medal by

in 1993, * Oliver E. Buckley Prize by the

(1995) * Moet Hennessey Louis Vuitton (LVMH) Science for Art Prize (1997) *IEEE Edison Medal (1998) ''For pioneering contributions to the physics of computing and conduction.'' *The Rolf Landauer Medal of the International ETOPIM Association (2009) 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).

References

External links

The 'Landauer' formula
{{DEFAULTSORT:Landauer, Rolf Stuyvesant High School alumni Members of the United States National Academy of Sciences 1927 births 1999 deaths IBM Fellows Harvard University alumni Fellows of the IEEE German information theorists Members of the United States National Academy of Engineering IEEE Edison Medal recipients 20th-century German physicists Members of the European Academy of Sciences and Arts American information theorists Oliver E. Buckley Condensed Matter Prize winners People from Briarcliff Manor, New York Jewish German physicists Jewish emigrants from Nazi Germany to the United States Mathematicians from New York (state) Deaths from brain cancer in New York (state) Fellows of the American Physical Society Jewish American physicists

Biography

Awards and honors

See also

References

Further reading

External links