physics

Rolf Landauer

Rolf Landauer is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rolf Landauer rather than just read about it. In short: Rolf William Landauer (February 4, 1927 – April 27, 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. Born in Germany, he emigrated to the U.S. in 1938, obtained a Ph.D. in physics from Harvard in 1950, and then spent most of his career at IBM.

Key takeaways

Rolf Landauer belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Rolf Landauer to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Rolf Landauer from memory before moving on to harder problems.

Reference excerpt

Rolf William Landauer (February 4, 1927 – April 27, 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. Born in Germany, he emigrated to the U.S. in 1938, obtained a Ph.D. in physics from Harvard in 1950, and then spent most of his career at IBM. 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. 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.

Biography 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. His advisor was initially Léon Brillouin but he finished the thesis under the supervision of Wendell H. Furry. He first worked for two years at NASA, then known as the National Advisory Committee for Aeronautics, at its Glenn Research Center, then known as the Lewis Research Center, in Cleveland. At the age of 25, he began a career in semiconductors at IBM Research. 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 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 Member, National Academy of Engineering Member, National Academy of Sciences Member, European Academy of Sciences and Arts Fellow, American Academy of Arts and Sciences Honorary doctorate, Technion in Israel 1991 Scott Lecturer at the Cavendish Laboratory at Cambridge University 1992 Stuart Ballantine Medal of the Franklin Institute Centennial Medal by Harvard in 1993, Oliver E. Buckley Prize by the American Physical Society (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).

See also Persistent current Tunnel ionization

References

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

External links The 'Landauer' formula Stuyvesant math team Physicists confirm Landauer's conjecture

Illustrations

Worked examples

Example 1 — a first encounter with Rolf Landauer

Start with the simplest possible case. Write down what Rolf Landauer claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rolf Landauer before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rolf Landauer ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rolf Landauer

In research: Rolf Landauer appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Rolf Landauer in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Rolf Landauer is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1927 births, 1999 deaths, 20th-century American physicists, so understanding it makes those chapters shorter.
In everyday life: Look for Rolf Landauer outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rolf Landauer in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rolf Landauer means in your own words.
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Frequently asked questions

What is Rolf Landauer in simple terms?

Why does Rolf Landauer matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rolf Landauer?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rolf Landauer.