was a theoretical physicist. He studied various topics, such as the time reversal of quantum mechanics, pattern recognition, cognitive science, and the concept of time. He was the first physicist who claimed that quantum probability theory is time-asymmetric (irreversible; non-invariant under time reversal), and reject the conventional analysis of the time reversal of probability laws. He developed the Double Inferential Vector Formalism (DIVF), later known as the

Two-state vector formalism The two-state vector formalism (TSVF) is a description of quantum mechanics in terms of a causal relation in which the present is caused by quantum states of the past and of the future taken in combination. Theory The two-state vector formalism is ...

( TSVF), which is sometimes interpreted as contradicting his claim of time-asymmetry, but this is a misunderstanding. He also proposed the

Ugly duckling theorem The ugly duckling theorem is an argument showing that classification is not really possible without some sort of bias. More particularly, it assumes finitely many properties combinable by logical connectives, and finitely many objects; it asserts ...

Early life and education

Satosi Watanabe was born on May 26, 1910, in

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.46 ...

. He attended Gakushuuin Middle High School and Tokyo High School. In 1933, he graduated from

Tokyo Imperial University , abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project by ...

in theoretical physics, where

Torahiko Terada was a Japanese physicist and author who was born in Tokyo. He was a professor at Tokyo Imperial University, a researcher at RIKEN, and worked on a wide range of topics in physics. He was also a professor at the Earthquake Research Institute. As ...

was his teacher. The imperial government sent him to France to study.

Louis de Broglie Louis Victor Pierre Raymond, 7th Duc de Broglie (, also , or ; 15 August 1892 – 19 March 1987) was a French physicist and aristocrat who made groundbreaking contributions to Old quantum theory, quantum theory. In his 1924 PhD thesis, he pos ...

encouraged Watanabe to study

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

and

wave mechanics Wave mechanics may refer to: * the mechanics of waves * the ''wave equation'' in quantum physics, see Schrödinger equation See also * Quantum mechanics * Wave equation The (two-way) wave equation is a second-order linear partial different ...

. In 1937, he moved to

Leipzig Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as ...

and started to study nuclear theory under Heisenberg. In the same year, Watanabe married Dorothea Dauer, a scholar of German literature. In 1939, at the beginning of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

, he left Germany and stayed with

Niels Bohr Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922 ...

for a time. In December, he returned to Japan with his family.

Career

In Japan, he worked at the Physical and Chemical Research Institute (''Rikagaku Kenkyujo'') at Tokyo Imperial University as an assistant professor, and as a physics professor at Rikkyo University. In 1950, he left for the United States. His argument that quantum mechanics is time-asymmetric (irreversible; non-invariant under the time reversal transformation) is repeated in a number of his papers (1955; 1965; 1966; 1972). This result means that physicists have used the wrong transformation of probability laws to represent time reversal, and the claims that quantum mechanics is time reversal invariant are invalid. Watanabe's argument has not been accepted by physicists or philosophers however. The assumption that quantum mechanics is time symmetric on the basis of conventional proofs is almost universal in the literature on time in physics to this day. He developed the Double Inferential Vector Formalism (DIVF), later known as the

( TSVF). The DSVF/TSVF is often interpreted as a time-symmetric interpretation of quantum mechanics (see

Minority interpretations of quantum mechanics There is a diversity of views that propose interpretations of quantum mechanics. They vary in how many physicists accept or reject them. An interpretation of quantum mechanics is a conceptual scheme that proposes to relate the mathematical formal ...

). However Watanabe considered that the normal physical theory of quantum mechanics that holds for real physics is time-asymmetric. He consequently rejected the conventional view that physical time asymmetry is only explained by asymmetric boundary conditions on the universe, and claimed it is a law-like feature of quantum physics. Time-symmetric interpretations of quantum mechanics were first suggested by

Walter Schottky Walter Hans Schottky (23 July 1886 – 4 March 1976) was a German physicist who played a major early role in developing the theory of electron and ion emission phenomena, invented the screen-grid vacuum tube in 1915 while working at Siemen ...

in 1921, and later by several other scientists. Watanabe proposed that information given by forwards evolving

quantum state In quantum physics, a quantum state is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system. Knowledge of the quantum state together with the rules for the system's evolution i ...

s is not complete; rather, both forwards and backwards evolving quantum states are required to describe a quantum state: a first state vector that evolves from the initial conditions towards the future, and a second state vector that evolves backwards in time from future boundary conditions. Past and future measurements, taken together, provide complete information about a quantum system. Watanabe's work was later rediscovered by

Yakir Aharonov Yakir Aharonov ( he, יקיר אהרונוב; born August 28, 1932) is an Israeli physicist specializing in quantum physics. He has been a Professor of Theoretical Physics and the James J. Farley Professor of Natural Philosophy at Chapman Univer ...

Peter Bergmann Peter Gabriel Bergmann (24 March 1915 – 19 October 2002) was a German-American physicist best known for his work with Albert Einstein on a unified field theory encompassing all physical interactions. He also introduced primary and secondar ...

and

Joel Lebowitz Joel Louis Lebowitz (born May 10, 1930) is a mathematical physicist widely acknowledged for his outstanding contributions to statistical physics, statistical mechanics and many other fields of Mathematics and Physics. Lebowitz has published ...

in 1964, who later renamed it the

( TSVF).Yakir Aharonov, Lev Vaidman: ''Protective measurements of two-state vectors'', in: Robert Sonné Cohen, Michael Horne, John J. Stachel (eds.): ''Potentiality, Entanglement and Passion-At-A-Distance'', Quantum Mechanical Studies for A. M. Shimony, Volume Two, 1997, , pp. 1–8
p. 2
/ref> In 1956, he became a researcher at the IBM Watson Laboratory and started to build his own information theory based on quantum mechanics. He taught at Yale University and the

University of Hawaii A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...

, became chairman of the International Time Academy, and was the Vice President of International Philosophy Academy. On October 15, 1993, he died in Tokyo.

Family

His father, Chifuyu Watanabe, was a Minister of Justice at Second Wakatsuki Cabinet. His elder brother, Takeshi Watanabe, was Vice Minister of Finance for International Affairs and director general of Asia Development Bank. His wife, Dorothea Dauer Watanabe, was a professor of German (language and literature) at the University of Hawaii. His son, Hajime Watanabe, is a professor of philosophy at the

University of California, Santa Barbara The University of California, Santa Barbara (UC Santa Barbara or UCSB) is a public land-grant research university in Santa Barbara, California with 23,196 undergraduates and 2,983 graduate students enrolled in 2021–2022. It is part of the U ...

References

Bibliography

* ''Le deuxième théorème de la thermodynamique et la mécanique ondulatoire'', Paris : Herman et Cie, 1935 * ''Knowing and guessing : a quantitative study of inference and information'', New York : John Wiley & Sons, 1969 * ''Pattern recognition : human and mechanical'', New York : John Wiley & Sons, 1985

External links

Publication list
at

DBLP DBLP is a computer science bibliography website. Starting in 1993 at Universität Trier in Germany, it grew from a small collection of HTML files and became an organization hosting a database and logic programming bibliography site. Since Novem ...

{{DEFAULTSORT:Watanabe, Satosi 1910 births 1993 deaths Japanese physicists People from Tokyo Theoretical physicists University of Tokyo alumni Riken personnel Fellows of the American Physical Society