Hans Bethe
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Hans Albrecht Eduard Bethe (; ; July 2, 1906 – March 6, 2005) was a German-American
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 major contributions to
nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies th ...
,
astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...
,
quantum electrodynamics In particle physics, quantum electrodynamics (QED) is the Theory of relativity, relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quant ...
and
solid-state physics Solid-state physics is the study of rigid matter, or solids, through methods such as solid-state chemistry, quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state phy ...
, and received the
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
in 1967 for his work on the theory of
stellar nucleosynthesis In astrophysics, stellar nucleosynthesis is the creation of chemical elements by nuclear fusion reactions within stars. Stellar nucleosynthesis has occurred since the original creation of hydrogen, helium and lithium during the Big Bang. As a ...
. For most of his career, Bethe was a professor at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
.James C. Keck Collected Works and Biography
() has the class notes taken by one of Bethe's students at Cornell from the graduate courses on Nuclear Physics and on Applications of Quantum Mechanics he taught in the spring of 1947.
In 1931, Bethe developed the
Bethe ansatz In physics, the Bethe ansatz is an ansatz for finding the exact wavefunctions of certain quantum many-body models, most commonly for one-dimensional lattice models. It was first used by Hans Bethe in 1931 to find the exact eigenvalues and eigenv ...
, which is a method for finding the exact solutions for the
eigenvalues In linear algebra, an eigenvector ( ) or characteristic vector is a vector that has its direction unchanged (or reversed) by a given linear transformation. More precisely, an eigenvector \mathbf v of a linear transformation T is scaled by a ...
and
eigenvectors In linear algebra, an eigenvector ( ) or characteristic vector is a Vector (mathematics and physics), vector that has its direction (geometry), direction unchanged (or reversed) by a given linear map, linear transformation. More precisely, an e ...
of certain one-dimensional quantum many-body models. In 1939, Bethe published a paper which established the
CNO cycle In astrophysics, the carbon–nitrogen–oxygen (CNO) cycle, sometimes called Bethe–Weizsäcker cycle, after Hans Albrecht Bethe and Carl Friedrich von Weizsäcker, is one of the two known sets of fusion reactions by which stars convert h ...
as the primary energy source for heavier stars in the
main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...
classification of stars, which earned him a Nobel Prize in 1967. During
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
, Bethe was head of the Theoretical Division at the secret
Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development Laboratory, laboratories of the United States Department of Energy National Laboratories, United States Department of Energy ...
that developed the first
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear expl ...
s. There he played a key role in calculating the
critical mass In nuclear engineering, critical mass is the minimum mass of the fissile material needed for a sustained nuclear chain reaction in a particular setup. The critical mass of a fissionable material depends upon its nuclear properties (specific ...
of the weapons and developing the theory behind the implosion method used in both the
Trinity test Trinity was the first detonation of a nuclear weapon, conducted by the United States Army at 5:29 a.m. MWT (11:29:21 GMT) on July 16, 1945, as part of the Manhattan Project. The test was of an implosion-design plutonium bomb, or "gadg ...
and the "
Fat Man "Fat Man" (also known as Mark III) was the design of the nuclear weapon the United States used for seven of the first eight nuclear weapons ever detonated in history. It is also the most powerful design to ever be used in warfare. A Fat Man ...
" weapon dropped on Nagasaki in August 1945. After the war, Bethe played an important role in the development of the
hydrogen bomb A thermonuclear weapon, fusion weapon or hydrogen bomb (H-bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lo ...
, as he also served as the head of the theoretical division for the project, although he had originally joined the project with the hope of proving it could not be made. He later campaigned with
Albert Einstein Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ...
and the
Emergency Committee of Atomic Scientists The Emergency Committee of Atomic Scientists (ECAS) was founded by Albert Einstein and Leó Szilárd in May, 1946, primarily as a fundraising and policy-making agency. Its aims were to warn the public of the dangers associated with the developmen ...
against
nuclear testing Nuclear weapons tests are experiments carried out to determine the performance of nuclear weapons and the effects of Nuclear explosion, their explosion. Nuclear testing is a sensitive political issue. Governments have often performed tests to si ...
and the
nuclear arms race The nuclear arms race was an arms race competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War. During this same period, in addition to the American and Soviet nuc ...
. He helped persuade the Kennedy and
Nixon administration Richard Nixon's tenure as the 37th president of the United States began with his first inauguration on January 20, 1969, and ended when he resigned on August 9, 1974, in the face of almost certain impeachment and removal from office, the ...
s to sign, respectively, the 1963
Partial Nuclear Test Ban Treaty The Partial Test Ban Treaty (PTBT), formally known as the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, prohibited all nuclear weapons testing, test detonations of nuclear weapons except for those co ...
and 1972
Anti-Ballistic Missile Treaty The Anti-Ballistic Missile Treaty, also known as the ABM Treaty or ABMT, was an arms control treaty between the United States and the Soviet Union on the limitation of the anti-ballistic missile (ABM) systems used in defending areas against ball ...
( SALT I). In 1947, he wrote an important paper which provided the calculation of the
Lamb shift In physics, the Lamb shift, named after Willis Lamb, is an anomalous difference in energy between two electron orbitals in a hydrogen atom. The difference was not predicted by theory and it cannot be derived from the Dirac equation, which pre ...
, which is credited with revolutionizing quantum electrodynamics and further "opened the way to the modern era of
particle physics Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the s ...
". He contributed to the understanding of
neutrinos A neutrino ( ; denoted by the Greek letter ) is an elementary particle that interacts via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that it ...
and was key in the solving of the solar neutrino problem. He contributed to the understanding of supernovas and their processes. His scientific research never ceased, and he was publishing papers well into his nineties, making him one of the few scientists to have published at least one major paper in his field during every decade of his career, which in Bethe's case spanned nearly seventy years. Physicist
Freeman Dyson Freeman John Dyson (15 December 1923 – 28 February 2020) was a British-American theoretical physics, theoretical physicist and mathematician known for his works in quantum field theory, astrophysics, random matrix, random matrices, math ...
, once his doctoral student, called him "the supreme problem-solver of the 20th century", and cosmologist Edward Kolb called him "the last of the old masters" of physics.


Early life

Bethe was born in
Strasbourg Strasbourg ( , ; ; ) is the Prefectures in France, prefecture and largest city of the Grand Est Regions of France, region of Geography of France, eastern France, in the historic region of Alsace. It is the prefecture of the Bas-Rhin Departmen ...
, which at the time was part of the Reichsland Elsaß-Lothringen,
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 ...
, on July 2, 1906, the only child of Anna (née Kuhn) and Albrecht Bethe, a of physiology at the
University of Strasbourg The University of Strasbourg (, Unistra) is a public research university located in Strasbourg, France, with over 52,000 students and 3,300 researchers. Founded in the 16th century by Johannes Sturm, it was a center of intellectual life during ...
. Although his mother, the daughter of Abraham Kuhn, professor at the University of Strasbourg, had a
Jewish Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of History of ancient Israel and Judah, ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, rel ...
background, Bethe was raised
Protestant Protestantism is a branch of Christianity that emphasizes Justification (theology), justification of sinners Sola fide, through faith alone, the teaching that Salvation in Christianity, salvation comes by unmerited Grace in Christianity, divin ...
, like his father; and he became an
atheist Atheism, in the broadest sense, is an absence of belief in the existence of deities. Less broadly, atheism is a rejection of the belief that any deities exist. In an even narrower sense, atheism is specifically the position that there no ...
later in life. His father accepted a position as professor and director of the Institute of Physiology at the
University of Kiel Kiel University, officially the Christian Albrecht University of Kiel, (, abbreviated CAU, known informally as Christiana Albertina) is a public research university in the city of Kiel, Germany. It was founded in 1665 as the ''Academia Holsator ...
in 1912, and the family moved into the director's apartment at the institute. Initially, he was schooled privately by a professional teacher as part of a group of eight girls and boys. The family moved again in 1915 when his father became the head of the new Institute of Physiology at the
Goethe University Frankfurt Goethe University Frankfurt () is a public research university located in Frankfurt am Main, Germany. It was founded in 1914 as a citizens' university, which means it was founded and funded by the wealthy and active liberal citizenry of Frankfurt ...
. Bethe attended the in
Frankfurt Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...
, Germany. His education was interrupted in 1916, when he contracted
tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...
, and he was sent to
Bad Kreuznach Bad Kreuznach () is a town in the Bad Kreuznach (district), Bad Kreuznach district in Rhineland-Palatinate, Germany. It is a spa town, known for its medieval bridge dating from around 1300, the Alte Nahebrücke (Bad Kreuznach), Alte Nahebrücke, ...
to recuperate. By 1917, he had recovered sufficiently to attend the local and the following year, he was sent to the , a private, coeducational
boarding school A boarding school is a school where pupils live within premises while being given formal instruction. The word "boarding" is used in the sense of "room and board", i.e. lodging and meals. They have existed for many centuries, and now extend acr ...
. He attended the again for his final three years of secondary schooling, from 1922 to 1924. Having passed his , Bethe entered the University of Frankfurt in 1924. He decided to major in
chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...
. The instruction in physics was poor, and while there were distinguished mathematicians in Frankfurt such as
Carl Ludwig Siegel Carl Ludwig Siegel (31 December 1896 – 4 April 1981) was a German mathematician specialising in analytic number theory. He is known for, amongst other things, his contributions to the Thue–Siegel–Roth theorem in Diophantine approximation, ...
and Otto Szász, Bethe disliked their approaches, which presented mathematics without reference to the other sciences. Bethe found that he was a poor experimentalist who destroyed his lab coat by spilling
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...
on it, but he found the advanced physics taught by the associate professor, Walter Gerlach, more interesting. Gerlach left in 1925 and was replaced by Karl Meissner, who advised Bethe that he should go to a university with a better school of theoretical physics, specifically the
University of Munich The Ludwig Maximilian University of Munich (simply University of Munich, LMU or LMU Munich; ) is a public university, public research university in Munich, Bavaria, Germany. Originally established as the University of Ingolstadt in 1472 by Duke ...
, where he could study under
Arnold Sommerfeld Arnold Johannes Wilhelm Sommerfeld (; 5 December 1868 – 26 April 1951) was a German Theoretical physics, theoretical physicist who pioneered developments in Atomic physics, atomic and Quantum mechanics, quantum physics, and also educated and ...
. Bethe entered the University of Munich in April 1926, where Sommerfeld took him on as a student on Meissner's recommendation. Sommerfeld taught an advanced course on differential equations in physics, which Bethe enjoyed. Because he was such a renowned scholar, Sommerfeld frequently received advance copies of scientific papers, which he put up for discussion at weekly evening seminars. When Bethe arrived, Sommerfeld had just received
Erwin Schrödinger Erwin Rudolf Josef Alexander Schrödinger ( ; ; 12 August 1887 – 4 January 1961), sometimes written as or , was an Austrian-Irish theoretical physicist who developed fundamental results in quantum field theory, quantum theory. In particul ...
's papers on wave mechanics. For his
PhD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...
thesis, Sommerfeld suggested that Bethe examine
electron diffraction Electron diffraction is a generic term for phenomena associated with changes in the direction of electron beams due to elastic interactions with atoms. It occurs due to elastic scattering, when there is no change in the energy of the electrons. ...
in
crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
s. As a starting point, Sommerfeld suggested Paul Ewald's 1914 paper on
X-ray diffraction X-ray diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. ...
in crystals. Bethe later recalled that he became too ambitious, and, in pursuit of greater accuracy, his calculations became unnecessarily complicated. When he met
Wolfgang Pauli Wolfgang Ernst Pauli ( ; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and a pioneer of quantum mechanics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics "for the ...
for the first time, Pauli told him: "After Sommerfeld's tales about you, I had expected much better from you than your thesis." "I guess from Pauli," Bethe later recalled, "that was a compliment."


Early work

After Bethe received his doctorate, Erwin Madelung offered him an assistantship in Frankfurt, and in September 1928 Bethe moved in with his father, who had recently divorced his mother. His father had met Vera Congehl earlier that year and married her in 1929. They had two children, Doris, born in 1933, and Klaus, born in 1934. Bethe did not find the work in Frankfurt very stimulating, and in 1929 he accepted an offer from Ewald at the ''
Technische Hochschule A ''Technische Hochschule'' (, plural: ''Technische Hochschulen'', abbreviated ''TH'') is a type of university focusing on engineering sciences in Germany. Previously, it also existed in Austria, Switzerland, the Netherlands (), and Finland (, ) ...
'' 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 ...
. While there, he wrote what he considered to be his greatest paper, ''Zur Theorie des Durchgangs schneller Korpuskularstrahlen durch Materie'' ("The Theory of the Passage of Fast Corpuscular Rays Through Matter"). Starting from
Max Born Max Born (; 11 December 1882 – 5 January 1970) was a German-British theoretical physicist who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics, and supervised the work of a ...
's interpretation of the
Schrödinger equation The Schrödinger equation is a partial differential equation that governs the wave function of a non-relativistic quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. It is named after E ...
, Bethe produced a simplified formula for collision problems using a
Fourier transform In mathematics, the Fourier transform (FT) is an integral transform that takes a function as input then outputs another function that describes the extent to which various frequencies are present in the original function. The output of the tr ...
, which is known today as the Bethe formula. He submitted this paper for his ''
habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excelle ...
'' in 1930. Sommerfeld recommended Bethe for a
Rockefeller Foundation The Rockefeller Foundation is an American private foundation and philanthropic medical research and arts funding organization based at 420 Fifth Avenue, New York City. The foundation was created by Standard Oil magnate John D. Rockefeller (" ...
Travelling Scholarship in 1929. This provided $150 a month (about $,000 in dollars) to study abroad. In 1930, Bethe chose to do postdoctoral work 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 ...
at the
University of Cambridge 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 ...
in England, where he worked under the supervision of Ralph Fowler. At the request of
Patrick Blackett Patrick Maynard Stuart Blackett, Baron Blackett (18 November 1897 – 13 July 1974) was an English physicist who received the 1948 Nobel Prize in Physics. In 1925, he was the first person to prove that radioactivity could cause the nuclear tr ...
, who was working with
cloud chamber A cloud chamber, also known as a Wilson chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic ...
s, Bethe created a relativistic version of the Bethe formula. Bethe was known for his sense of humor, and with Guido Beck and , two other postdoctoral
research fellow A research fellow is an academic research position at a university or a similar research institution, usually for academic staff or faculty members. A research fellow may act either as an independent investigator or under the supervision of a p ...
s, created a hoax paper ''On the Quantum Theory of the Temperature of Absolute Zero'' where he calculated the
fine structure constant In physics, the fine-structure constant, also known as the Sommerfeld constant, commonly denoted by (the Greek letter ''alpha''), is a fundamental physical constant that quantifies the strength of the electromagnetic interaction between ele ...
from the absolute zero temperature in Celsius units. The paper poked fun at a certain class of papers in theoretical physics of the day, which were purely speculative and based on spurious numerical arguments, such as
Arthur Eddington Sir Arthur Stanley Eddington, (28 December 1882 – 22 November 1944) was an English astronomer, physicist, and mathematician. He was also a philosopher of science and a populariser of science. The Eddington limit, the natural limit to the lu ...
's attempts to explain the value of the
fine structure constant In physics, the fine-structure constant, also known as the Sommerfeld constant, commonly denoted by (the Greek letter ''alpha''), is a fundamental physical constant that quantifies the strength of the electromagnetic interaction between ele ...
from fundamental quantities in an earlier paper. They were forced to issue an apology. For the second half of his scholarship, Bethe chose to go to
Enrico Fermi Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian and naturalized American physicist, renowned for being the creator of the world's first artificial nuclear reactor, the Chicago Pile-1, and a member of the Manhattan Project ...
's laboratory in Rome in February 1931. He was greatly impressed by Fermi and regretted that he had not gone to Rome first. Bethe developed the
Bethe ansatz In physics, the Bethe ansatz is an ansatz for finding the exact wavefunctions of certain quantum many-body models, most commonly for one-dimensional lattice models. It was first used by Hans Bethe in 1931 to find the exact eigenvalues and eigenv ...
, a method for finding the exact solutions for the
eigenvalue In linear algebra, an eigenvector ( ) or characteristic vector is a vector that has its direction unchanged (or reversed) by a given linear transformation. More precisely, an eigenvector \mathbf v of a linear transformation T is scaled by a ...
s and
eigenvector In linear algebra, an eigenvector ( ) or characteristic vector is a vector that has its direction unchanged (or reversed) by a given linear transformation. More precisely, an eigenvector \mathbf v of a linear transformation T is scaled by ...
s of certain one-dimensional quantum many-body models. He was influenced by Fermi's simplicity and Sommerfeld's rigor in approaching problems and these qualities influenced his own later research. The Rockefeller Foundation offered an extension of Bethe's fellowship, allowing him to return to Italy in 1932. In the meantime, Bethe worked for Sommerfeld in Munich as a ''privatdozent''. Since Bethe was fluent in English, Sommerfeld had Bethe supervise all his English-speaking postdoctoral fellows, including Lloyd P. Smith from
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
. Bethe accepted a request from
Karl Scheel Karl Friedrich Franz Christian Scheel (10 March 1866 in Rostock – 8 November 1936 in Berlin) was a German physicist. He was a senior executive officer and head of Department IIIb at the Reich Physical and Technical Institute. Additionally, ...
to write an article for the ''Handbuch der Physik'' on the
quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...
of hydrogen and helium. Reviewing the article decades later,
Robert Bacher Robert Fox Bacher (August 31, 1905November 18, 2004) was an American nuclear physics, nuclear physicist and one of the leaders of the Manhattan Project. Born in Loudonville, Ohio, Bacher obtained his undergraduate degree and doctorate from the U ...
and
Victor Weisskopf Victor Frederick "Viki" Weisskopf (also spelled Viktor; September 19, 1908 – April 22, 2002) was an Austrian-born American theoretical physicist. He did postdoctoral work with Werner Heisenberg, Erwin Schrödinger, Wolfgang Pauli, and Niels Boh ...
noted that it was unusual in the depth and breadth of its treatment of the subject that required very little updating for the 1959 edition. Bethe was then asked by Sommerfeld to help him with the ''handbuch'' article on electrons in metals. The article covered the basis of what is now called
solid state physics Solid-state physics is the study of rigid matter, or solids, through methods such as solid-state chemistry, quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state p ...
. Bethe took a very new field and provided a clear, coherent, and complete coverage of it. His work on the ''handbuch'' articles occupied most of his time in Rome, but he also co-wrote a paper with Fermi on another new field,
quantum electrodynamics In particle physics, quantum electrodynamics (QED) is the Theory of relativity, relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quant ...
, describing the relativistic interactions of charged particles. In 1932, Bethe accepted an appointment as an assistant professor at the
University of Tübingen The University of Tübingen, officially the Eberhard Karl University of Tübingen (; ), is a public research university located in the city of Tübingen, Baden-Württemberg, Germany. The University of Tübingen is one of eleven German Excellenc ...
, where
Hans Geiger Johannes Wilhelm Geiger ( , ; ; 30 September 1882 – 24 September 1945) was a German nuclear physicist. He is known as the inventor of the Geiger counter, a device used to detect ionizing radiation, and for carrying out the Rutherford scatt ...
was the professor of experimental physics. One of the first laws passed by the new
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 ...
government was the
Law for the Restoration of the Professional Civil Service The Law for the Restoration of the Professional Civil Service (, shortened to ''Berufsbeamtengesetz''), also known as Civil Service Law, Civil Service Restoration Act, and Law to Re-establish the Civil Service, was enacted by the Nazi Party, Na ...
. Due to his Jewish background, Bethe was dismissed from his job at the university, which was a government post. Geiger refused to help, but Sommerfeld immediately gave Bethe back his fellowship at Munich. Sommerfeld spent much of the summer term of 1933 finding places for Jewish students and colleagues. Bethe left Germany in 1933, moving to England after receiving an offer for a position as lecturer at the
University of Manchester The University of Manchester is a public university, public research university in Manchester, England. The main campus is south of Manchester city centre, Manchester City Centre on Wilmslow Road, Oxford Road. The University of Manchester is c ...
for a year through Sommerfeld's connection to
William Lawrence Bragg Sir William Lawrence Bragg (31 March 1890 – 1 July 1971) was an Australian-born British physicist who shared the 1915 Nobel Prize in Physics with his father William Henry Bragg "for their services in the analysis of crystal structure by ...
. He moved in with his friend
Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...
and Peierls' wife Genia. Peierls was a fellow German physicist who had also been barred from academic positions in Germany because he was Jewish. This meant that Bethe had someone to speak to in German and he did not have to eat English food. Their relationship was professional as well as personal. Peierls aroused Bethe's interest in
nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies th ...
. After
James Chadwick Sir James Chadwick (20 October 1891 – 24 July 1974) was an English nuclear physicist who received the Nobel Prize in Physics in 1935 for his discovery of the neutron. In 1941, he wrote the final draft of the MAUD Report, which inspired t ...
and Maurice Goldhaber discovered the
photodisintegration Photodisintegration (also called phototransmutation, or a photonuclear reaction) is a nuclear process in which an atomic nucleus absorbs a high-energy gamma ray, enters an excited state, and immediately decays by emitting a subatomic particle. The ...
of
deuterium Deuterium (hydrogen-2, symbol H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen; the other is protium, or hydrogen-1, H. The deuterium nucleus (deuteron) contains one proton and one neutron, whereas the far more c ...
, Chadwick challenged Bethe and Peierls to come up with a theoretical explanation of this phenomenon. This they did on the four-hour train ride from Cambridge back to Manchester. Bethe would investigate further in the years ahead. In 1933, the physics department at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
,
New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...
, was looking for a new theoretical physicist, and Lloyd Smith strongly recommended Bethe. This was supported by Bragg, who was visiting Cornell at the time. In August 1934, Cornell offered Bethe a position as an acting assistant professor. Bethe had already accepted a fellowship for a year to work with
Nevill Mott Sir Nevill Francis Mott (30 September 1905 – 8 August 1996) was a British physicist who won the Nobel Prize for Physics in 1977 for his work on the electronic structure of magnetic and disordered systems, especially amorphous semiconductor ...
at the
University of Bristol The University of Bristol is a public university, public research university in Bristol, England. It received its royal charter in 1909, although it can trace its roots to a Merchant Venturers' school founded in 1595 and University College, Br ...
for a semester, but Cornell agreed to let him start in the spring of 1935. Before leaving for the United States, he visited the
Niels Bohr Institute The Niels Bohr Institute () is a research institute of the University of Copenhagen. The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics, and biophysics. Overview The institute was foun ...
in
Copenhagen Copenhagen ( ) is the capital and most populous city of Denmark, with a population of 1.4 million in the Urban area of Copenhagen, urban area. The city is situated on the islands of Zealand and Amager, separated from Malmö, Sweden, by the ...
in September 1934, where he proposed to Hilde Levi, who accepted. The match was opposed by Bethe's mother, who despite having a Jewish background, did not want him to marry a Jewish woman. A few days before their wedding date in December, Bethe broke off their engagement.
Niels Bohr Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the No ...
and
James Franck James Franck (; 26 August 1882 – 21 May 1964) was a German-American physicist who received the 1925 Nobel Prize in Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom". He completed hi ...
were so shocked by this action by Bethe that he was not invited to the institute again until after
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
.


United States

Bethe arrived in the United States in February 1935, and joined the faculty at Cornell University on a salary of $3,000. Bethe's appointment was part of a deliberate effort on the part of the new head of its physics department, Roswell Clifton Gibbs, to move into nuclear physics. Gibbs had hired Stanley Livingston, who had worked with
Ernest Lawrence Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was an American accelerator physicist who received the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation for ...
, to build a
cyclotron A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Januar ...
at Cornell. To complete the team, Cornell needed an experimentalist, and, on the advice of Bethe and Livingston, recruited
Robert Bacher Robert Fox Bacher (August 31, 1905November 18, 2004) was an American nuclear physics, nuclear physicist and one of the leaders of the Manhattan Project. Born in Loudonville, Ohio, Bacher obtained his undergraduate degree and doctorate from the U ...
. Bethe received requests to visit
Columbia University Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...
from
Isidor Isaac Rabi Israel Isidor Isaac Rabi (; ; July 29, 1898 – January 11, 1988) was an American nuclear physicist who received the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance imaging. H ...
,
Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...
from
Edward Condon Edward Uhler Condon (March 2, 1902 – March 26, 1974) was an American nuclear physicist, a pioneer in quantum mechanics, and a participant during World War II in the development of radar and, very briefly, of nuclear weapons as part of the Ma ...
,
University of Rochester The University of Rochester is a private university, private research university in Rochester, New York, United States. It was founded in 1850 and moved into its current campus, next to the Genesee River in 1930. With approximately 30,000 full ...
from Lee DuBridge,
Purdue University Purdue University is a Public university#United States, public Land-grant university, land-grant research university in West Lafayette, Indiana, United States, and the flagship campus of the Purdue University system. The university was founded ...
from Karl Lark-Horovitz, the
University of Illinois at Urbana–Champaign The University of Illinois Urbana-Champaign (UIUC, U of I, Illinois, or University of Illinois) is a public land-grant research university in the Champaign–Urbana metropolitan area, Illinois, United States. Established in 1867, it is the f ...
from Francis Wheeler Loomis, and
Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...
from
John Hasbrouck Van Vleck John Hasbrouck Van Vleck (; March 13, 1899 – October 27, 1980) was an American physicist and mathematician. He was co-awarded the Nobel Prize in Physics in 1977, for his contributions to the understanding of the behavior of electronic magnetis ...
. Gibbs moved to prevent Bethe from being poached by having him appointed as a regular assistant professor in 1936, with an assurance that promotion to professor would soon follow. Together with Bacher and Livingston, Bethe published a series of three articles, which summarized most of what was known on the subject of nuclear physics until that time, an account that became known informally as "Bethe's Bible". It remained the standard work on the subject for many years. In this account, he also continued where others left off, filling in gaps in the older literature. Loomis offered Bethe a full professorship at the University of Illinois at Urbana–Champaign, but Cornell matched the position offered, and the salary of $6,000. He wrote to his mother: On March 17, 1938, Bethe attended the Carnegie Institute and
George Washington University The George Washington University (GW or GWU) is a Private university, private University charter#Federal, federally-chartered research university in Washington, D.C., United States. Originally named Columbian College, it was chartered in 1821 by ...
's fourth annual Washington Conference on Theoretical Physics. There were only 34 invited attendees, but they included
Gregory Breit Gregory Breit (, ; July 14, 1899 – September 13, 1981) was an American physicist born in Mykolaiv, Russian Empire (now Mykolaiv, Ukraine). He was a professor at New York University (1929–1934), University of Wisconsin–Madison (1934–194 ...
,
Subrahmanyan Chandrasekhar Subrahmanyan Chandrasekhar (; 19 October 1910 – 21 August 1995) was an Indian Americans, Indian-American theoretical physicist who made significant contributions to the scientific knowledge about the structure of stars, stellar evolution and ...
,
George Gamow George Gamow (sometimes Gammoff; born Georgiy Antonovich Gamov; ; 4 March 1904 – 19 August 1968) was a Soviet and American polymath, theoretical physicist and cosmologist. He was an early advocate and developer of Georges Lemaître's Big Ba ...
, Donald Menzel,
John von Neumann John von Neumann ( ; ; December 28, 1903 – February 8, 1957) was a Hungarian and American mathematician, physicist, computer scientist and engineer. Von Neumann had perhaps the widest coverage of any mathematician of his time, in ...
,
Bengt Strömgren Bengt Georg Daniel Strömgren (21 January 1908 – 4 July 1987) was a Danish astronomer and astrophysicist. Life and career Bengt Strömgren was born in Gothenburg. His parents were Hedvig Strömgren (née Lidforss) and Elis Strömgren, wh ...
,
Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...
, and
Merle Tuve Merle Anthony Tuve (June 27, 1901 – May 20, 1982) was an American geophysicist who was the Chairman of the Office of Scientific Research and Development's Section T, which was created in August 1940. He was founding director of the Johns Hopkin ...
. Bethe initially declined the invitation to attend, because the conference's topic, stellar energy generation, did not interest him, but Teller persuaded him to go. At the conference, Strömgren detailed what was known about the temperature, density, and chemical composition of the Sun, and challenged the physicists to come up with an explanation. Gamow and
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
had proposed in a 1937 paper that the Sun's energy was the result of a proton–proton chain reaction: : But this did not account for the observation of elements heavier than helium. By the end of the conference, Bethe, working in collaboration with Charles Critchfield, had come up with a series of subsequent nuclear reactions that explained how the Sun shines: : That this did not explain the processes in heavier stars was not overlooked. At the time there were doubts about whether the proton–proton cycle described the processes in the Sun, but more recent measurements of the Sun's core temperature and luminosity show that it does. When he returned to Cornell, Bethe studied the relevant
nuclear reaction In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two atomic nucleus, nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a t ...
s and reaction cross sections, leading to his discovery of the carbon-nitrogen-oxygen cycle (CNO cycle): : The two papers, one on the proton–proton cycle, co-authored with Critchfield, and the other on the carbon-oxygen-nitrogen (CNO) cycle, were sent to the ''
Physical Review ''Physical Review'' is a peer-reviewed scientific journal. The journal was established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the Ame ...
'' for publication. After ''
Kristallnacht ( ) or the Night of Broken Glass, also called the November pogrom(s) (, ), was a pogrom against Jews carried out by the Nazi Party's (SA) and (SS) paramilitary forces along with some participation from the Hitler Youth and German civilia ...
'', Bethe's mother had become afraid to remain in Germany. Taking advantage of her Strasbourg origin, she was able to emigrate to the United States in June 1939 on the French quota, rather than the German one, which was full. Bethe's graduate student Robert Marshak noted that the
New York Academy of Sciences The New York Academy of Sciences (NYAS), originally founded as the Lyceum of Natural History in January 1817, is a nonprofit professional society based in New York City, with more than 20,000 members from 100 countries. It is the fourth-oldes ...
was offering a $500 prize for the best unpublished paper on the topic of solar and stellar energy. So Bethe, in need of $250 to release his mother's furniture, withdrew the CNO cycle paper and sent it in to the New York Academy of Sciences. It won the prize, and Bethe gave Marshak $50 finder's fee and used $250 to release his mother's furniture. The paper was subsequently published in the ''Physical Review'' in March. It was a breakthrough in the understanding of the stars, and would win Bethe the
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
in 1967. In 2002, at age 96, Bethe sent a handwritten note to John N. Bahcall congratulating him on the use of solar neutrino observations to show that the CNO cycle accounts for approximately 7% of the Sun's energy; the neutrino observations had started with Raymond Davis Jr., whose experiment was based on Bahcall's calculations and encouragement, and the note led to Davis's receiving a share of the 2002 Nobel Prize. Bethe married Rose Ewald, the daughter of Paul Ewald, on September 13, 1939, in a simple civil ceremony. She had emigrated to the United States and was a student at Duke University and they met while Bethe was lecturing there in 1937. They had two children, Henry and Monica. (Henry was a
contract bridge Contract bridge, or simply bridge, is a trick-taking game, trick-taking card game using a standard 52-card deck. In its basic format, it is played by four players in two Team game, competing partnerships, with partners sitting opposite each othe ...
expert and former husband of Kitty Munson Cooper.) Bethe became a
naturalized citizen Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...
of the United States in March 1941. Writing to Sommerfeld in 1947, Bethe confided that "I am much more at home in America than I ever was in Germany. As if I was born in Germany only by mistake, and only came to my true homeland at 28."


Manhattan Project

When the Second World War began, Bethe wanted to contribute to the war effort, but was unable to work on classified projects until he became a citizen. Following the advice of the
Caltech The California Institute of Technology (branded as Caltech) is a private university, private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small g ...
aerodynamicist
Theodore von Kármán Theodore von Kármán ( , May 11, 1881May 6, 1963) was a Hungarian-American mathematician, aerospace engineer, and physicist who worked in aeronautics and astronautics. He was responsible for crucial advances in aerodynamics characterizing ...
, Bethe collaborated with his friend Edward Teller on a theory of shock waves that are generated by the passage of a projectile through a gas. Bethe considered it one of their most influential papers. He also worked on a theory of armor penetration, which was immediately classified by the army, thus making it impossible for Bethe (who was not an American citizen at the time) to access further research on the theory. After receiving security clearance in December 1941, Bethe joined the
MIT Radiation Laboratory The Radiation Laboratory, commonly called the Rad Lab, was a microwave and radar research laboratory located at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. It was first created in October 1940 and operated until 3 ...
, where he invented the Bethe-hole directional coupler, which is used in
microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...
waveguide A waveguide is a structure that guides waves by restricting the transmission of energy to one direction. Common types of waveguides include acoustic waveguides which direct sound, optical waveguides which direct light, and radio-frequency w ...
s such as those used in
radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
sets. In Chicago in June 1942, and then in July at the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
, he participated in a series of meetings at the invitation of Robert Oppenheimer, which discussed the first designs for the
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear expl ...
. They went over the preliminary calculations by
Robert Serber Robert Serber (March 14, 1909 – June 1, 1997) was an American physicist who participated in the Manhattan Project. Serber's lectures explaining the basic principles and goals of the project were printed and supplied to all incoming scientific st ...
, Stan Frankel, and others, and discussed the possibilities of using
uranium-235 Uranium-235 ( or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nat ...
and
plutonium Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four ...
. (Teller then raised the prospect of a thermonuclear device, Teller's "Super" bomb. At one point Teller asked if the nitrogen in the atmosphere could be set alight. It fell to Bethe and Emil Konopinski to perform the calculations demonstrating the virtual impossibility of such an occurrence.) "The fission bomb had to be done," he later recalled, "because the Germans were presumably doing it." When Oppenheimer was put in charge of forming a secret weapons design laboratory, Los Alamos, he appointed Bethe director of the T (Theoretical) Division, the laboratory's smallest, but most prestigious division. This move irked the equally qualified, but more difficult to manage Teller and
Felix Bloch Felix Bloch (; ; 23 October 1905 – 10 September 1983) was a Swiss-American physicist who shared the 1952 Nobel Prize in Physics with Edward Mills Purcell "for their development of new methods for nuclear magnetic precision measurements and di ...
, who had coveted the job. A series of disagreements between Bethe and Teller between February and June 1944 over the relative priority of Super research led to Teller's group being removed from T Division and placed directly under Oppenheimer. In September it became part of Fermi's new F Division. Bethe's work at Los Alamos included calculating the
critical mass In nuclear engineering, critical mass is the minimum mass of the fissile material needed for a sustained nuclear chain reaction in a particular setup. The critical mass of a fissionable material depends upon its nuclear properties (specific ...
and efficiency of
uranium-235 Uranium-235 ( or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nat ...
and the multiplication of
nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...
in an exploding atomic bomb. Along with
Richard Feynman Richard Phillips Feynman (; May 11, 1918 – February 15, 1988) was an American theoretical physicist. He is best known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of t ...
, he developed a formula for calculating the bomb's explosive yield. After August 1944, when the laboratory was reorganized and reoriented to solve the problem of the implosion of the
plutonium Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four ...
bomb, Bethe spent much of his time studying the hydrodynamic aspects of implosion, a job that he continued into 1944. In 1945, he worked on the
neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...
initiator, and later, on radiation propagation from an exploding atomic bomb. The Trinity nuclear test validated the accuracy of T Division's results. When it was detonated in the New Mexico desert on July 16, 1945, Bethe's immediate concern was for its efficient operation, and not its moral implications. He is reported to have commented: "I am not a philosopher."


Hydrogen bomb

After the war, Bethe argued that a crash project for the
hydrogen bomb A thermonuclear weapon, fusion weapon or hydrogen bomb (H-bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lo ...
should not be attempted, although after President
Harry Truman Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. As the 34th vice president in 1945, he assumed the presidency upon the death of Franklin D. Roosevelt that year. Subsequen ...
announced the beginning of such a project and the outbreak of the
Korean War The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...
, Bethe signed up and played a key role in the weapon's development. Although he saw the project through to its end, Bethe had hoped that it would be impossible to create the hydrogen bomb. He later remarked in 1968 on the apparent contradiction in his stance, having first opposed the development of the weapon and later helping to create it: As for his own role in the project and its relation to the dispute over who was responsible for the design, Bethe later said that: In 1954, Bethe testified on behalf of
J. Robert Oppenheimer J. Robert Oppenheimer (born Julius Robert Oppenheimer ; April 22, 1904 – February 18, 1967) was an American theoretical physics, theoretical physicist who served as the director of the Manhattan Project's Los Alamos Laboratory during World ...
during the
Oppenheimer security hearing Over four weeks in 1954, the United States Atomic Energy Commission (AEC) explored the background, actions, and associations of J. Robert Oppenheimer, the American scientist who directed the Los Alamos Laboratory during World War II as part of t ...
. Specifically, Bethe argued that Oppenheimer's stances against developing the hydrogen bomb in the late 1940s had not hindered its development, a topic which was seen as a key motivating factor behind the hearing. Bethe contended that the developments that led to the successful
Teller–Ulam design A thermonuclear weapon, fusion weapon or hydrogen bomb (H-bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lowe ...
were a matter of serendipity and not a question of manpower or logical development of previously existing ideas. During the hearing, Bethe and his wife also tried hard to persuade
Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...
against testifying. However, Teller did not agree, and his testimony played a major role in the revocation of Oppenheimer's
security clearance A security clearance is a status granted to individuals allowing them access to classified information (state or organizational secrets) or to restricted areas, after completion of a thorough background check. The term "security clearance" is ...
. While Bethe and Teller had been on very good terms during the prewar years, the conflict between them during the
Manhattan Project The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the ...
, and especially during the Oppenheimer episode, permanently marred their relationship.


Later work


Lamb shift

After the war ended, Bethe returned to Cornell. In June 1947, he participated in the Shelter Island Conference. Sponsored by 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 ...
and held at the Ram's Head Inn on
Shelter Island, New York Shelter Island is an island Administrative divisions of New York#Town, town in eastern Suffolk County, New York, Suffolk County, New York (state), New York, United States, near the eastern end of Long Island. The population was 3,253 at the time ...
, the conference on the "Foundations of Quantum Mechanics" was the first major physics conference held after the war. It was a chance for American physicists to come together, pick up where they had left off before the war, and establish the direction of post-war research. A major talking point at the conference was the discovery by
Willis Lamb Willis Eugene Lamb Jr. (; July 12, 1913 – May 15, 2008) was an American physicist who shared the 1955 Nobel Prize in Physics with Polykarp Kusch "for his discoveries concerning the fine structure of the hydrogen spectrum". Lamb was able to p ...
and his graduate student, Robert Retherford, shortly before the conference began that one of the two possible quantum states of hydrogen atoms had slightly more energy than that predicted by the theory of
Paul Dirac Paul Adrien Maurice Dirac ( ; 8 August 1902 – 20 October 1984) was an English mathematician and Theoretical physics, theoretical physicist who is considered to be one of the founders of quantum mechanics. Dirac laid the foundations for bot ...
; this became known as the
Lamb shift In physics, the Lamb shift, named after Willis Lamb, is an anomalous difference in energy between two electron orbitals in a hydrogen atom. The difference was not predicted by theory and it cannot be derived from the Dirac equation, which pre ...
. Oppenheimer and Weisskopf suggested that this was a result of
quantum fluctuation In quantum physics, a quantum fluctuation (also known as a vacuum state fluctuation or vacuum fluctuation) is the temporary random change in the amount of energy in a point in space, as prescribed by Werner Heisenberg's uncertainty principle. ...
s of the electromagnetic field, which gave the electron more energy. According to pre-war
quantum electrodynamics In particle physics, quantum electrodynamics (QED) is the Theory of relativity, relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quant ...
(QED), the energy of the electron consisted of the bare energy it had when uncoupled from an electromagnetic field, and the self-energy resulting from the electromagnetic coupling, but both were unobservable, since the electromagnetic field cannot be switched off. QED gave infinite values for the self-energies; but the Lamb shift showed that they were both real and finite.
Hans Kramers Hendrik Anthony "Hans" Kramers (17 December 1894 – 24 April 1952) was a Dutch physicist who worked with Niels Bohr to understand how electromagnetic waves interact with matter and made important contributions to quantum mechanics and statistica ...
proposed
renormalization Renormalization is a collection of techniques in quantum field theory, statistical field theory, and the theory of self-similar geometric structures, that is used to treat infinities arising in calculated quantities by altering values of the ...
as a solution, but no one knew how to do the calculation. Bethe managed to perform the calculation on the train from New York to
Schenectady Schenectady ( ) is a City (New York), city in Schenectady County, New York, United States, of which it is the county seat. As of the United States Census 2020, 2020 census, the city's population of 67,047 made it the state's ninth-most populo ...
, where he was working for
General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...
. He did so by realising that it was a non-relativistic process, which greatly simplified the calculation. The bare energy was easily removed as it was already included in the observed mass of the electron. The self energy term now increased logarithmically instead of linearly, making it mathematically convergent. Bethe arrived at a value for the Lamb shift of 1040 MHz, extremely close to that obtained experimentally by Lamb and Retherford. His paper, published in the ''Physical Review'' in August 1947, was only three pages long and contained just twelve mathematical equations, but was enormously influential. It had been presumed that the infinities indicated that QED was fundamentally flawed, and that a new, radical theory was required; Bethe demonstrated that this was not necessary. His calculation of the Lamb shift has been called "the most important discovery in the history of the theory of quantum electrodynamics" by the physicist
Richard Feynman Richard Phillips Feynman (; May 11, 1918 – February 15, 1988) was an American theoretical physicist. He is best known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of t ...
, while physicist Paul Dirac called it "the most important calculation in physics for decades". One of Bethe's most famous papers is one he never wrote: the 1948
Alpher–Bethe–Gamow paper In physical cosmology, the Alpher–Bethe–Gamow paper, or αβγ paper, was created by Ralph Alpher, then a physics PhD student, his advisor George Gamow, and Hans Bethe. The work, which would become the subject of Alpher's PhD dissertation, a ...
.
George Gamow George Gamow (sometimes Gammoff; born Georgiy Antonovich Gamov; ; 4 March 1904 – 19 August 1968) was a Soviet and American polymath, theoretical physicist and cosmologist. He was an early advocate and developer of Georges Lemaître's Big Ba ...
added Bethe's name (in absentia) without consulting him, knowing that Bethe would not mind, and against Ralph Alpher's wishes. This was apparently a reflection of Gamow's sense of humor, wanting to have a paper title that would sound like the first three letters of the Greek alphabet. As one of the ''Physical Review''s reviewers, Bethe saw the manuscript and struck out the words "in absentia".


Astrophysics

Bethe believed that the
atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford at the Department_of_Physics_and_Astronomy,_University_of_Manchester , University of Manchester ...
was like a quantum liquid drop. He investigated the
nuclear matter Nuclear matter is an idealized system of interacting nucleons (protons and neutrons) that exists in several phase (matter), phases of exotic matter that, as of yet, are not fully established. It is ''not'' matter in an atomic nucleus, but a ...
problem by considering the work conducted by Keith Brueckner on
perturbation theory In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle ...
. Working with
Jeffrey Goldstone Jeffrey Goldstone (born 3 September 1933) is a Great Britain, British theoretical physicist and an ''emeritus'' physics faculty member at the MIT MIT Center for Theoretical Physics, Center for Theoretical Physics. He worked at the University of ...
, he produced a solution for the case where there was an infinite hard-core potential. Then, working with Baird Brandow and Albert Petschek, he came up with an approximation that converted the
scattering In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiat ...
equation into an easily solved differential equation. This then led him to the Bethe-Faddeev equation, a generalisation of
Ludvig Faddeev Ludvig Dmitrievich Faddeev (also ''Ludwig Dmitriyevich''; ; 23 March 1934 – 26 February 2017) was a Soviet Union, Soviet and Russian Mathematical physics, mathematical physicist. He is known for the discovery of the Faddeev equations in the qu ...
's approach to three-body scattering. He then used these techniques to examine the
neutron stars A neutron star is the gravitationally collapsed core of a massive supergiant star. It results from the supernova explosion of a massive star—combined with gravitational collapse—that compresses the core past white dwarf star density to th ...
, which have densities similar to those of nuclei. Bethe continued to do research on
supernovae A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original ob ...
, neutron stars,
black holes A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...
, and other problems in theoretical astrophysics into his late nineties. In doing this, he collaborated with Gerald E. Brown of
Stony Brook University Stony Brook University (SBU), officially the State University of New York at Stony Brook, is a public university, public research university in Stony Brook, New York, United States, on Long Island. Along with the University at Buffalo, it is on ...
. In 1978, Brown proposed that they collaborate on supernovae. These were reasonably well understood by this time, but the calculations were still a problem. Using techniques honed from decades of working with nuclear physics, and some experience with calculations involving nuclear explosions, Bethe tackled the problems involved in stellar
gravitational collapse Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity. Gravitational collapse is a fundamental mechanism for structure formati ...
, and the way in which various factors affected a supernova explosion. Once again, he was able to reduce the problem to a set of differential equations, and to solve them. At age 85, Bethe wrote an important article about the solar neutrino problem, in which he helped establish the conversion mechanism for
electron neutrino The electron neutrino () is an elementary particle which has zero electric charge and a spin of . Together with the electron, it forms the first generation of leptons, hence the name ''electron neutrino''. It was first hypothesized by Wolfga ...
s into
muon neutrino The muon neutrino is an elementary particle which has the symbol and zero electric charge. Together with the muon it forms the second generation of leptons, hence the name muon neutrino. It was discovered in 1962 by Leon Lederman, Melvin Schwa ...
s proposed by Stanislav Mikheyev, Alexei Smirnov, and
Lincoln Wolfenstein Lincoln Wolfenstein (February 10, 1923 – March 27, 2015) was an American particle physics, particle physicist who studied the weak interaction. Wolfenstein was born in 1923 and obtained his PhD in 1949 from the University of Chicago. He retire ...
to explain a vexing discrepancy between theory and experiment. Bethe argued that physics beyond the
Standard Model The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...
was required to understand the solar neutrino problem, because it presumed that neutrinos have no mass, and therefore, cannot metamorphosize into each other; whereas the MSW effect required this to occur. Bethe hoped that corroborating evidence would be found by the
Sudbury Neutrino Observatory The Sudbury Neutrino Observatory (SNO) was a neutrino observatory located 2100 m underground in Vale's Creighton Mine in Sudbury, Ontario, Canada. The detector was designed to detect solar neutrinos through their interactions with a larg ...
(SNO) in
Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
by his 90th birthday, but he did not get the call from SNO until June 2001, when he was nearly 95. In 1996,
Kip Thorne Kip Stephen Thorne (born June 1, 1940) is an American theoretical physicist and writer known for his contributions in gravitational physics and astrophysics. Along with Rainer Weiss and Barry C. Barish, he was awarded the 2017 Nobel Pri ...
approached Bethe and Brown about
LIGO The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool. Prior to LIG ...
, the Laser Interferometer Gravitational-Wave Observatory designed to detect the gravitational waves from merging neutron stars and black holes. Since Bethe and Brown were good at calculating things that could not be seen, could they look at the mergers? The 90-year-old Bethe quickly became enthused and soon began the required calculations. The result was a 1998 paper on the "Evolution of Binary Compact Objects Which Merge", which Brown regarded as the best that the two produced together.


Political stances

In 1968, Bethe, along with IBM physicist
Richard Garwin Richard Lawrence Garwin (April 19, 1928 – May 13, 2025) was an American physicist and government advisor, best known as the author of the first hydrogen bomb design. In 1978, Garwin was elected a member of the National Academy of Engineering ...
, published an article criticising in detail the anti-
ICBM An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
defense system proposed by the
Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an executive department of the U.S. federal government charged with coordinating and supervising the six U.S. armed services: the Army, Navy, Marines, Air Force, Space Force, ...
. The two physicists described in the article that nearly any measure taken by the United States would be easily thwarted with the deployment of relatively simple decoys. Bethe was one of the primary voices in the scientific community behind the signing of the 1963
Partial Test Ban Treaty The Partial Test Ban Treaty (PTBT), formally known as the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, prohibited all nuclear weapons testing, test detonations of nuclear weapons except for those co ...
prohibiting further atmospheric testing of nuclear weapons. During the 1980s and 1990s, Bethe campaigned for the peaceful use of
nuclear energy Nuclear energy may refer to: *Nuclear power, the use of sustained nuclear fission or nuclear fusion to generate heat and electricity *Nuclear binding energy, the energy needed to fuse or split a nucleus of an atom *Nuclear potential energy, the pot ...
. After the
Chernobyl disaster On 26 April 1986, the no. 4 reactor of the Chernobyl Nuclear Power Plant, located near Pripyat, Ukrainian Soviet Socialist Republic, Ukrainian SSR, Soviet Union (now Ukraine), exploded. With dozens of direct casualties, it is one of only ...
, Bethe was part of a committee of experts who analysed the incident. They concluded that the reactor suffered from a fundamentally faulty design and also that human error had contributed significantly to the accident. "My colleagues and I established," he explained "that the Chernobyl disaster tells us about the deficiencies of the Soviet political and administrative system rather than about problems with nuclear power." Throughout his life Bethe remained a strong advocate for electricity from nuclear energy, which he described in 1977 as "a necessity, not merely an option." In the 1980s he and other physicists opposed the
Strategic Defense Initiative The Strategic Defense Initiative (SDI) was a proposed missile defense system intended to protect the United States from attack by ballistic nuclear missiles. The program was announced in 1983, by President Ronald Reagan. Reagan called for a ...
missile system conceived by the
Ronald Reagan Ronald Wilson Reagan (February 6, 1911 – June 5, 2004) was an American politician and actor who served as the 40th president of the United States from 1981 to 1989. He was a member of the Republican Party (United States), Republican Party a ...
administration. In 1995, at the age of 88, Bethe wrote an open letter calling on all scientists to "cease and desist" from working on any aspect of nuclear weapons development and manufacture. In 2004, he joined 47 other
Nobel laureate The Nobel Prizes (, ) are awarded annually by the Royal Swedish Academy of Sciences, the Swedish Academy, the Karolinska Institutet, and the Norwegian Nobel Committee to individuals and organizations who make outstanding contributions in th ...
s in signing a letter endorsing
John Kerry John Forbes Kerry (born December 11, 1943) is an American attorney, politician, and diplomat who served as the 68th United States secretary of state from 2013 to 2017 in the Presidency of Barack Obama#Administration, administration of Barac ...
for President of the United States as someone who would "restore science to its appropriate place in government". Historian Gregg Herken wrote:


Personal life

Bethe's hobbies included a passion for stamp-collecting. He loved the outdoors and was an enthusiastic hiker all his life, exploring the
Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...
and the Rockies. He died in his home in
Ithaca, New York Ithaca () is a city in and the county seat of Tompkins County, New York, United States. Situated on the southern shore of Cayuga Lake in the Finger Lakes region of New York (state), New York, Ithaca is the largest community in the Ithaca metrop ...
, on March 6, 2005, of congestive heart failure. He was survived by his wife, Rose Ewald Bethe, and their two children. At the time of his death, he was the John Wendell Anderson Professor of Physics, Emeritus, at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
.


Honors and awards

Bethe received numerous honors and awards in his lifetime and afterward. He became a
Fellow A fellow is a title and form of address for distinguished, learned, or skilled individuals in academia, medicine, research, and industry. The exact meaning of the term differs in each field. In learned society, learned or professional society, p ...
of the
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 ...
in 1947, and that year, he also received 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 ...
's
Henry Draper Medal The Henry Draper Medal is awarded every 4 years by the United States National Academy of Sciences "for investigations in astronomical physics". Named after Henry Draper, the medal is awarded with a gift of USD $15,000. The medal was established ...
and was elected to the
American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
. He was awarded the
Max Planck Medal The Max Planck Medal is the highest award of the German Physical Society , the world's largest organization of physicists, for extraordinary achievements in theoretical physics. The prize has been awarded annually since 1929, with few exceptions ...
in 1955, the
Franklin Medal The Franklin Medal was a science award presented from 1915 until 1997 by the Franklin Institute located in Philadelphia, Pennsylvania, U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country ...
in 1959, the
Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...
Eddington Medal The Eddington Medal is awarded by the Royal Astronomical Society for investigations of outstanding merit in theoretical astrophysics. It is named after Sir Arthur Eddington. First awarded in 1953, the frequency of the prize has varied over the ye ...
and the
United States Atomic Energy Commission The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by the U.S. Congress to foster and control the peacetime development of atomic science and technology. President Harry ...
Enrico Fermi Award The Enrico Fermi Award is a scientific award conferred by the President of the United States. It is awarded to honor scientists of international stature for their lifetime achievement in the development, use or production of energy. It was establ ...
in 1961, the
Rumford Prize Founded in 1796, the Rumford Prize, awarded by the American Academy of Arts and Sciences, is one of the oldest scientific prizes in the United States. The prize recognizes contributions by scientists to the fields of heat and light. These terms ...
in 1963, the
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
in 1967, the
National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral science, behavior ...
in 1975, the
Oersted Medal The Oersted Medal recognizes notable contributions to the teaching of physics. Established in 1936, it is awarded by the American Association of Physics Teachers. The award is named for Hans Christian Ørsted. It is the Association's most presti ...
in 1993, the
Bruce Medal The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was ...
in 2001, and posthumously in 2005, the Benjamin Franklin Medal for Distinguished Achievement in the Sciences by the
American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
. Bethe was elected Foreign Member of the Royal Society (ForMemRS) in 1957, and he gave the 1993
Bakerian Lecture The Bakerian Medal is one of the premier medals of the Royal Society that recognizes exceptional and outstanding science. It comes with a medal award and a prize lecture. The medalist is required to give a lecture on any topic related to physical ...
at the Royal Society on the Mechanism of Supernovae. In 1978 he was elected a Member of the
German Academy of Sciences Leopoldina The German National Academy of Sciences Leopoldina (), in short Leopoldina, is the national academy of Germany, and is located in Halle (Saale). Founded on 1 January 1652, based on academic models in Italy, it was originally named the ''Academi ...
. Cornell named the third of five new
residential college A residential college is a division of a university that places academic activity in a community setting of students and faculty, usually at a residence and with shared meals, the college having a degree of autonomy and a federated relationship ...
s, each of which is named after a distinguished former member of the Cornell faculty, as the Hans Bethe House after him. Similarly named after him is the Hans Bethe Center, 322 Fourth Street NE, Washington, D.C., home to the Council for a Livable World, where Bethe was a longtime board member, as well as the Bethe Center for Theoretical Physics at
University of Bonn The University of Bonn, officially the Rhenish Friedrich Wilhelm University of Bonn (), is a public research university in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the () on 18 October 1818 by Frederick Willi ...
in Germany. An
asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
, 30828 Bethe, that was discovered in 1990 was named after him. 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 ...
Hans Bethe Prize was named after him as well.


Selected publications

* Bethe, H. A
"Theory of High Frequency Rectification by Silicon Crystals"
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) Radiation Laboratory,
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
(through predecessor agency the Atomic Energy Commission), (October 29, 1942). * Bethe, H. A
"Theoretical Estimate of Maximum Possible Nuclear Explosion"
Knolls Atomic Power Laboratory-Schenectady, N.Y.,
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
(through predecessor agency the Atomic Energy Commission), (January 31, 1950). * Bethe, H. A.; Rajaraman, R
"Three-body Problem in Nuclear Matter"
University of Southern California-Los Angeles,
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
(through predecessor agency the Atomic Energy Commission), (1967). * Bethe, H. A
"Note on Inverse Bremsstrahlung in a Strong Electromagnetic Field"
Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development Laboratory, laboratories of the United States Department of Energy National Laboratories, United States Department of Energy ...
(LANL),
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
(through predecessor agency the Atomic Energy Commission), (September 1972). * Bethe, H. A
"Pauli Principle and Pion Scattering"
Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development Laboratory, laboratories of the United States Department of Energy National Laboratories, United States Department of Energy ...
(LANL),
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
(through predecessor agency the Atomic Energy Commission), (October 1972). * Bethe, H. A
"Fusion Hybrid Reactor"
Sandia National Laboratories Sandia National Laboratories (SNL), also known as Sandia, is one of three research and development laboratories of the United States Department of Energy's National Nuclear Security Administration (NNSA). Headquartered in Kirtland Air Force B ...
,
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
, (August 1981).


See also

*
Hydrogen anion The hydrogen anion, H−, is a negative ion of hydrogen, that is, a hydrogen atom that has captured an extra electron. The hydrogen anion is an important constituent of the atmosphere of stars, such as the Sun. In chemistry, this ion is called ...
*
List of Jewish Nobel laureates Of the 965 individual recipients of the Nobel Prize and the Nobel Memorial Prize in Economic Sciences between 1901 and 2023, at least 216 have been Jews or people with at least one Jewish parent, representing 22% of all recipients. Jews constitut ...


Notes


Citations


References

* * * * * * * * * *


External links


1986 Video Interview
War and Peace in the Nuclear Age
1993 Audio Interview with Hans Bethe by Richard Rhodes
Voices of the Manhattan Project
1982 Audio Interview with Hans Bethe by Martin Sherwin
Voices of the Manhattan Project
2014 Video Interview with Rose Bethe by Cynthia C. Kelly
Voices of the Manhattan Project

from the Cornell University
Text of the Eddington Medal award speech
*
Obituaries An obituary (obit for short) is an article about a recently deceased person. Newspapers often publish obituaries as news articles. Although obituaries tend to focus on positive aspects of the subject's life, this is not always the case. Acco ...
*
Hans Bethe obituary
from
The Economist ''The Economist'' is a British newspaper published weekly in printed magazine format and daily on Electronic publishing, digital platforms. It publishes stories on topics that include economics, business, geopolitics, technology and culture. M ...
magazine *
Hans Bethe obituary
from
The Guardian ''The Guardian'' is a British daily newspaper. It was founded in Manchester in 1821 as ''The Manchester Guardian'' and changed its name in 1959, followed by a move to London. Along with its sister paper, ''The Guardian Weekly'', ''The Guardi ...
Newspaper
Annotated bibliography for Hans Bethe from the Alsos Digital Library for Nuclear Issues

Oral History interview transcript with Hans Bethe on 17 January 1964, American Institute of Physics, Niels Bohr Library and Archives
– interviewed by Thomas S. Kuhn in Dwinelle Hall at
UC Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkele ...

Oral History interview transcript with Hans Bethe on 27 October 1966, American Institute of Physics, Niels Bohr Library and Archives
– Session I, interviewed by Charles Weiner and
Jagdish Mehra Jagdish Mehra (April 8, 1931 – September 14, 2008) was an Indian–American physicist and historian of science. Academic career Mehra was educated at Allahabad University, the Max Planck Institut für Physik and the University of California ...
at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

Oral History interview transcript with Hans Bethe on 17 November 1967, American Institute of Physics, Niels Bohr Library and Archives
– Session II, interviewed by Charles Weiner at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

Oral History interview transcript with Hans Bethe on 8 May 1972, American Institute of Physics, Niels Bohr Library and Archives
– Session III, interviewed by Charles Weiner at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

Oral History interview transcript with Hans Bethe on 29 April 1981, American Institute of Physics, Niels Bohr Library and Archives
– interviewed by
Lillian Hoddeson Lillian Hartman Hoddeson (born 20 December 1940, in New York City) is an American historian of science, specializing in the history of physics and technology during the 2nd half of the 20th century. Education and career Hoddeson received in 1957 a ...
in
Sicily Sicily (Italian language, Italian and ), officially the Sicilian Region (), is an island in the central Mediterranean Sea, south of the Italian Peninsula in continental Europe and is one of the 20 regions of Italy, regions of Italy. With 4. ...

Video of a talk entitled "Writing the Biography of a Living Scientist: Hans Bethe,"
delivered by S.S. Schweber
Hans Bethe tells his life story
at
Web of Stories Web of Stories is an online collection of thousands of autobiographical video-stories. Web of Stories, originally known as Science Archive, was set up to record the life stories of scientists. When it expanded to include the lives of authors, mov ...
* * * * {{DEFAULTSORT:Bethe, Hans 20th-century American physicists 20th-century German physicists Nobel laureates in Physics American Nobel laureates German Nobel laureates American nuclear physicists German nuclear physicists American quantum physicists German quantum physicists American theoretical physicists German theoretical physicists Jewish American physicists Jewish German physicists Rare earth scientists Manhattan Project people Cornell University faculty Academics of the Victoria University of Manchester Academic staff of Goethe University Frankfurt Academic staff of the University of Tübingen Enrico Fermi Award recipients Recipients of Franklin Medal Winners of the Max Planck Medal National Medal of Science laureates Niels Bohr International Gold Medal recipients Vannevar Bush Award recipients Alsatian-German people Alsatian Jews American atheists German atheists American people of German-Jewish descent Jewish emigrants from Nazi Germany to the United States Jewish American atheists People from Alsace-Lorraine Recipients of the Pour le Mérite (civil class) Goethe University Frankfurt alumni Ludwig Maximilian University of Munich alumni Foreign members of the Royal Society Foreign members of the Russian Academy of Sciences Fellows of the American Academy of Arts and Sciences Scientists from Strasbourg Members of JASON (advisory group) Members of the German National Academy of Sciences Leopoldina Fellows of the American Physical Society Presidents of the American Physical Society Members of the American Philosophical Society Aspen Center for Physics people 1906 births 2005 deaths