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 held at Chapel Hill, North Carolina, United States from January 18 to January 23, 1957. It discussed topics in general relativity, including the possible existence of gravitational waves and ways to find a theory of quantum gravity. It was also the first conference were the many-worlds interpretation was discussed. After the Chapel Hill Conference, conferences on general relativity and gravitation became frequent.

Contents

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 reviving the field with a younger generation of physicists. [1]

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 institute was financed by industrialist Agnew Hunter Bahnson. [1]

The conference was organized by physicists Cécile DeWitt-Morette and Bryce DeWitt. Aside from the DeWitts, in the steering comittee there was also Frederik Belinfante, Peter Bergmann, Freeman Dyson and John Archibald Wheeler. [2]

The conference was divided into 4 sessions on unquantized general relativity, a single session on cosmology, and 3 sessions on quantum gravity. [2]

The Chapel Hill Conference is considered part a still on-going series of modern conferences on gravitation, sometimes referred as GRn. [3] Chapel Hill Conference succeeded the 1955 Bern Conference held in the 50th anniversary of general 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. [4] [1]

Discussed topics

Lack of new experiments

After the introductory lecture by Wheeler, Robert H. Dicke reviewed the experimental tests of general relativity. He concluded that there was no much progress, he contrasted it with quantum mechanics: [5]

It is unfortunate to note that the situation with respect to the experimental checks of general relativity theory is not much better than it was a few years after the theory was discovered - say in 1920. This is in striking contrast to the situation with respect to quantum theory, where we have literally thousands of experimental checks... Professor Wheeler has already discussed the three famous checks of general relativity; this is really very flimsy evidence on which to hang a theory.

Dicke discussed the Eötvös experiment and provided ideas for further experiments. [6]

Gravitational waves

During the conference, the nature of gravitational waves and their ability to transfer energy was discussed. Richard Feynman remembers [7]

"I was surprised to find a whole day at the conference devoted to this question, and that ‘experts’ were confused. That is what comes from looking for conserved energy tensors, etc. instead of asking ‘can the waves do work?"

Felix Pirani presented for the first time how to mathematically treat gravitational waves using the geodesic deviation introduced by John Lighton Synge. [8] He showed how two masses would move relative from each other from ripples in spacetime. [8] Based on Pirani's argument, Feynman suggested during the conference the sticky bead argument which intuitively demonstrated that gravitational waves must carry energy. [7] [9] [8] A version of this argument was published by Hermann Bondi right after the conference. [7]

Wormholes

During the conference, Wheeler coined the term wormhole. [10]

Numerical relativity

When discussing the presentations of Yvonne Fourès-Bruhat and Charles W. Misner, Bruce DeWitt pointed out the importance of using computers to solve Einstein field equations. This line of research led to the development of numerical relativity. [11] [4]

Many-worlds interpretation

The relative state formulation, better known today as the many-worlds interpretation 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. [12] The paper was well received by Bryce DeWitt. [12] Wheeler and Charles W. Misner presented some of Everett's ideas near the end of the conference. [12] Feynman publicly criticized the idea of an universal wavefunction, suggested by Wheeler, saying [12]

"The concept of a 'universal wave function' has serious difficulties. This is so since the function must contain amplitudes for all possible worlds depending upon all quantum mechanical possibilities in the past and thus one is forced to believe in the equal reality of an infinity of possible worlds."

Everett's paper was published in the proceedings of the conference. [12]

List of participants

The list of participants according to DeWitt-Morette report is: [2]

Nathan Rosen was invited but did not participate.

Related Research Articles

<span class="mw-page-title-main">Many-worlds interpretation</span> Interpretation of quantum mechanics

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References

  1. 1 2 3 Rickles, Dean (2011-02-14), "The Chapel Hill Conference in Context", The Role of Gravitation in Physics: Report from the 1957 Chapel Hill Conference, EOS – Sources, Berlin: Max-Planck-Gesellschaft zur Förderung der Wissenschaften, ISBN   978-3-945561-29-4 , retrieved 2024-12-16
  2. 1 2 3 DeWitt, Cécile M.; Dicke, Dean, eds. (2017). The Role of Gravitation in Physics: Report from 1957 Chapel Hill Conference. EOS – Sources. Edition Open Access. ISBN   978-3-945561-29-4.
  3. ↑ "The GRn conferences". International Society on General Relativity and Gravitation. Retrieved 17 December 2024.
  4. 1 2 DeWitt-Morette, Cécile (2011-02-15). The Pursuit of Quantum Gravity: Memoirs of Bryce DeWitt from 1946 to 2004. Springer Science & Business Media. ISBN   978-3-642-14270-3.
  5. ↑ Peebles, P. J. E. (2022-08-02). The Whole Truth: A Cosmologist’s Reflections on the Search for Objective Reality. Princeton University Press. ISBN   978-0-691-23136-5.
  6. ↑ Bergmann, Peter G. (1957). "Summary of the Chapel Hill Conference". Reviews of Modern Physics. 29 (3): 352–354. doi:10.1103/RevModPhys.29.352.
  7. 1 2 3 Preskill, John and Kip S. Thorne. Foreword to Feynman Lectures On Gravitation. Feynman et al. (Westview Press; 1st ed. (June 20, 2002) p. xxv–xxvi.Link PDF (page 17-18)
  8. 1 2 3 Goenner, Hubert; Renn, Jürgen; Ritter, Jim; Sauer, Tilman (1998-12-01). The Expanding Worlds of General Relativity. Springer Science & Business Media. ISBN   978-0-8176-4060-6.
  9. ↑ Feynman, Richard (2018-05-04). Feynman Lectures On Gravitation. CRC Press. ISBN   978-0-429-98248-4.
  10. ↑ "Section III". Department of Physics and Astronomy. Retrieved 2024-12-16.
  11. ↑ Cervantes-Cota, Jorge L.; Galindo-Uribarri, Salvador; Smoot, George F. (2016). "A Brief History of Gravitational Waves". Universe. 2 (3): 22. arXiv: 1609.09400 . Bibcode:2016Univ....2...22C. doi: 10.3390/universe2030022 . ISSN   2218-1997.
  12. 1 2 3 4 5 Byrne, Peter (2012-12-13). The Many Worlds of Hugh Everett III: Multiple Universes, Mutual Assured Destruction, and the Meltdown of a Nuclear Family. OUP Oxford. ISBN   978-0-19-165522-7.
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