Chapel Hill Conference
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The Conference on the Role of Gravitation in Physics, better known as the Chapel Hill Conference or GR1, was an invitation-only international
scientific conference An academic conference or scientific conference (also congress, symposium, workshop, or meeting) is an event for researchers (not necessarily academics) to present and discuss their scholarly work. Together with academic or scientific journals a ...
held at
Chapel Hill, North Carolina Chapel Hill is a town in Orange County, North Carolina, Orange and Durham County, North Carolina, Durham counties, North Carolina, United States. Its population was 61,960 in the 2020 United States census, making Chapel Hill the List of municipa ...
, United States from January 18 to January 23, 1957. It discussed topics in
general relativity General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...
, including the possible existence of
gravitational wave Gravitational waves are oscillations of the gravitational field that Wave propagation, travel through space at the speed of light; they are generated by the relative motion of gravity, gravitating masses. They were proposed by Oliver Heaviside i ...
s and ways to find a theory of
quantum gravity Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics. It deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the v ...
. It was also the first conference where the
many-worlds interpretation The many-worlds interpretation (MWI) is an interpretation of quantum mechanics that asserts that the universal wavefunction is Philosophical realism, objectively real, and that there is no wave function collapse. This implies that all Possible ...
was discussed. After the Chapel Hill Conference, conferences on general relativity and gravitation became frequent. Historian Dean Rickles has suggested that the Chapel Hill Conference did for general relativity what the 1947 Shelter Island Conference did for
quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines Field theory (physics), field theory and the principle of relativity with ideas behind quantum mechanics. QFT is used in particle physics to construct phy ...
in reviving the field with a younger generation of physicists.


Organization

The conference was organized by the Institute of Field Physics established a year before the conference in the
University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill (UNC, UNC–Chapel Hill, or simply Carolina) is a public university, public research university in Chapel Hill, North Carolina, United States. Chartered in 1789, the university first began enrolli ...
. The institute was financed by industrialist Agnew Hunter Bahnson. The conference was organized by physicists Cécile DeWitt-Morette and Bryce DeWitt. Aside from the DeWitts, in the steering committee there was also Frederik Belinfante, Peter Bergmann,
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 ...
and
John Archibald Wheeler John Archibald Wheeler (July 9, 1911April 13, 2008) was an American theoretical physicist. He was largely responsible for reviving interest in general relativity in the United States after World War II. Wheeler also worked with Niels Bohr to e ...
. The conference was divided into 4 sessions on unquantized general relativity, a single session on cosmology, and 3 sessions on quantum gravity. The Chapel Hill Conference is considered part a still on-going series of modern conferences on gravitation, sometimes referred as GR''n.'' Chapel Hill Conference succeeded the 1955 Bern Conference held in the 50th anniversary of special relativity, the first ever conference focused entirely on the topic of gravitation. The Bern Conference was referred popularly as the GR0, while the Chapel Hill Conference was considered the GR1.


Discussed topics


Lack of new experiments

After the introductory lecture by Wheeler, Robert H. Dicke reviewed the experimental
tests of general relativity Tests of general relativity serve to establish observational evidence for the theory of general relativity. The first three tests, proposed by Albert Einstein in 1915, concerned the "anomalous" precession of the perihelion of Mercury (planet), Me ...
. He concluded that there was no much progress, he contrasted it with quantum mechanics: Dicke discussed the
Eötvös experiment The Eötvös experiment was a physics experiment that measured the correlation between inertial mass and gravitational mass, demonstrating that the two were one and the same, something that had long been suspected but never demonstrated with the ...
and provided ideas for further experiments.


Gravitational waves

During the conference, the nature of gravitational waves and their ability to transfer energy was discussed.
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 ...
remembersPreskill, John and Kip S. Thorne. Foreword to ''Feynman Lectures On Gravitation''. Feynman et al. (Westview Press; 1st ed. (June 20, 2002) p. xxv–xxv
Link PDF (page 17-18)
/ref> Felix Pirani presented for the first time how to mathematically treat gravitational waves using the geodesic deviation introduced by John Lighton Synge. He showed how two masses would move relative from each other from ripples in
spacetime In physics, spacetime, also called the space-time continuum, is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualiz ...
. Based on Pirani's argument, Feynman suggested during the conference the sticky bead argument which intuitively demonstrated that gravitational waves must carry energy. A version of this argument was published by
Hermann Bondi Sir Hermann Bondi (1 November 1919 – 10 September 2005) was an Austrian-British people, British mathematician and physical cosmology, cosmologist. He is best known for developing the steady state model of the universe with Fred Hoyle and Thom ...
right after the conference.


Wormholes

During the conference, Wheeler coined the term
wormhole A wormhole is a hypothetical structure that connects disparate points in spacetime. It can be visualized as a tunnel with two ends at separate points in spacetime (i.e., different locations, different points in time, or both). Wormholes are base ...
.


Numerical relativity

When discussing the presentations of Yvonne Fourès-Bruhat and Charles W. Misner, Bryce DeWitt pointed out the importance of using computers to solve
Einstein field equations In the General relativity, general theory of relativity, the Einstein field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of Matter#In general relativity and cosmology, matter within it. ...
. This line of research led to the development of
numerical relativity Numerical relativity is one of the branches of general relativity that uses numerical methods and algorithms to solve and analyze problems. To this end, supercomputers are often employed to study black holes, gravitational waves, neutron stars a ...
.


Many-worlds interpretation

The relative state formulation, better known today as the
many-worlds interpretation The many-worlds interpretation (MWI) is an interpretation of quantum mechanics that asserts that the universal wavefunction is Philosophical realism, objectively real, and that there is no wave function collapse. This implies that all Possible ...
of quantum mechanics, was being developed by Hugh Everett III, a student of Wheeler, who submitted an edited version of his thesis for the conference but did not attend. The paper was well received by Bryce DeWitt. Wheeler and Charles W. Misner presented some of Everett's ideas near the end of the conference. Feynman publicly criticized the idea of an
universal wavefunction The universal wavefunction or the wavefunction of the universe is the wavefunction or quantum state of the entire universe. It is regarded as the basic physical entity in the many-worlds interpretation of quantum mechanics,Hugh Everett, Relative St ...
, suggested by Wheeler, saying Everett's paper was published in the proceedings of the conference.


List of participants

The list of participants according to DeWitt-Morette report is:
Nathan Rosen Nathan Rosen (; March 22, 1909 – December 18, 1995) was an American and Israeli physicist noted for his study on the structure of the hydrogen molecule and his collaboration with Albert Einstein and Boris Podolsky on entangled wave functions and ...
was invited but did not participate.


References

{{reflist Physics conferences 1957 in science