Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Gravity-wave interferometers as quantum-gravity detectors


Nearly all theoretical approaches to the unification of quantum mechanics and gravity predict 1, 2, 3, 4 that, at very short distance scales, the classical picture of space-time breaks down, with space-time becoming somewhat ‘fuzzy’ (or ‘foamy’). The properties of this fuzziness and the length scale that characterizes itsonset are potentially a means for determining which (if any) of the existing models of quantum gravity is correct. But it is generally believed 5 that these quantum space-time effects are too small to be probed by technologies currently available. Here Iargue that modern gravity-wave interferometers are sensitive enough to test certain space-time fuzziness models, because quantum space-time effects should provide an additional source of noise in the interferometers that can be tightly constrained experimentally. The noise levels recently achieved in one interferometer 6 are sufficient to rule out values of the length scale that characterizes one of the space-time fuzziness models down to the Planck length (10 −35  m) and beyond, while the sensitivity required to test another model should be achievable with interferometers now under construction.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Wheeler, J. A. Relativity, Groups and Topology (eds De Witt, B. S. &De Witt, C. M.) (Gordon & Breach, New York, (1963).

    Google Scholar 

  2. 2

    Ashtekar, A., Rovelli, C. & Smolin, L. Weaving a classical geometry with quantum threads. Phys. Rev. Lett. 69, 237–240 (1992).

    ADS  MathSciNet  CAS  Article  PubMed  Google Scholar 

  3. 3

    Ellis, J., Mavromatos, N. & Nanopoulos, D. V. String theory modifies quantum mechanics. Phys. Lett. B 293, 37–48 (1992).

    ADS  MathSciNet  CAS  Article  Google Scholar 

  4. 4

    Hawking, S. W., Page, D. N. & Pope, C. N. Quantum gravitational bubbles. Nucl. Phys. B 170, 283–306 ( 1980).

    ADS  Article  Google Scholar 

  5. 5

    Isham, C. in Proc. 14th Int. Conf. on General Relativity and Gravitation (eds Francavaglia, M., Longhi, G., Lusanna, L. &Sorace, E.) (World Scientific, Singapores, (1997).

    Google Scholar 

  6. 6

    Abramovici, A. et al . Improved sensitivity in a gravitational wave interferometer and implications for LIGO. Phys. Lett. A 218, 157–163 (1996).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Garay, L. J. Quantum gravity and minimum length. Int. J. Mod. Phys. A 10, 145–166 (1995).

    ADS  Article  Google Scholar 

  8. 8

    Bergmann, P. G. & Smith, G. J. Measurability analysis of the linearized gravitational field. Gen. Rel. Grav. 14, 1131–1166 ( 1982).

    ADS  MathSciNet  Article  Google Scholar 

  9. 9

    Diosi, L. & Lukacs, B. On the minimum uncertainty of space-time geodesics. Phys. Lett. A 142, 331– 334 (1989).

    ADS  Article  Google Scholar 

  10. 10

    Ng, Y. J. & Van Dam, H. Limit to space-time measurement. Mod. Phys. Lett. A 9, 335– 348 (1994).

    ADS  Article  Google Scholar 

  11. 11

    Ahluwalia, D. V. Quantum measurement, gravitation, and locality. Phys. Lett. B 339, 301–303 (1994).

    ADS  CAS  Article  Google Scholar 

  12. 12

    Amelino-Camelia, G. Limits on the measurability of space-time distances in the semi-classical approximation of quantum gravity. Mod. Phys. Lett. A 9, 3415–3422 (1994).

    ADS  Article  Google Scholar 

  13. 13

    Amelino-Camelia, G. Dimensionful deformations of Poincaré symmetries for a Quantum Gravity without ideal observers. Mod. Phys. Lett. A 13, 1319–1325 (1998).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Wigner, E. P. Relativistic invariance and quantum phenomena. Rev. Mod. Phys. 29, 255–268 ( 1957).

    ADS  MathSciNet  Article  Google Scholar 

  15. 15

    Bohr, N. & Rosenfeld, L. Zur Frage der Messbarkeit der Electromagnetischen Feldgrössen. Kongelige Danske Videnskabernes Selskab Matematisk-Fysiske Meddelelser 12, 1– 65 (1933).

    MATH  Google Scholar 

  16. 16

    Radeka, V. Low-noise techniques in detectors. Annu. Rev. Nucl. Part. Sci. 38, 217–277 ( 1988).

    ADS  CAS  Article  Google Scholar 

  17. 17

    Karolyhazy, F. Gravitation and Quantum Mechanics of macroscopic objects. Il Nuovo Cimento A 42, 390–402 ( 1966).

    ADS  Article  Google Scholar 

  18. 18

    Colella, R., Overhauser, A. W. & Werner, S. A. Observation of gravitationally induced quantum interference. Phys. Rev. Lett. 34, 1472– 1474 (1975).

    ADS  CAS  Article  Google Scholar 

  19. 19

    Amati, D., Ciafaloni, M. & Veneziano, G. Superstring collisions at Planckian energies. Phys. Lett. B 197, 81–88 (1987).

    ADS  CAS  Article  Google Scholar 

  20. 20

    Kempf, A., Mangano, G. & Mann, R. B. Hilbert space representation of the minimal length uncertainty relation. Phys. Rev. D 52, 1108– 1118 (1995).

    ADS  MathSciNet  CAS  Article  Google Scholar 

  21. 21

    Lukierski, J., Nowicki, A. & Ruegg, H. Classical and quantum-mechanics of free κ-relativistic systems. Annu. Phys. 243, 90– 116 (1995).

    ADS  MathSciNet  CAS  Article  Google Scholar 

  22. 22

    Amelino-Camelia, G. Enlarged bound on the measurability of distances and quantum κ-Poincaré group. Phys. Lett. B 392, 283– 286 (1997).

    ADS  MathSciNet  CAS  Article  Google Scholar 

  23. 23

    Amelino-Camelia, G., Ellis, J., Mavromatos, N. E. & Nanopoulos, D. V. Distance measurement and wave dispersion in a Liouville string approach to quantum gravity. Int. J. Mod. Phys. A 12, 607–623 (1997).

    ADS  MathSciNet  Article  Google Scholar 

  24. 24

    Saulson, P. R. Fundamentals of Interferometric Gravitational Wave Detectors (World Scientific, Singapore, (1994).

    Book  Google Scholar 

  25. 25

    Abramovici, A. et al . LIGO: The Laser Interferometer Gravitational-Wave Observatory. Science 256, 325–333 (1992).

    ADS  CAS  Article  Google Scholar 

  26. 26

    Bradaschia, C. et al . The VIRGO project: a wide band antenna for gravitational wave detection. Nucl. Instrum. Meth. A 289, 518–525 (1990).

    ADS  Article  Google Scholar 

  27. 27

    Danzmann, K. LISA: Laser interferometer space antenna for gravitational wave measurements. Class. Quant. Grav. 13, A247– A250 (1996).

    ADS  Article  Google Scholar 

  28. 28

    Ellis, J., Hagelin, J. S., Nanopoulos, D. V. & Srednicki, M. Search for violations of Quantum Mechanics. Nucl. Phys. B 241, 381–405 (1984).

    ADS  MathSciNet  Article  Google Scholar 

  29. 29

    Amelino-Camelia, G., Ellis, J., Mavromatos, N. E., Nanopoulos, D. V. & Sarkar, S. Tests of quantum gravity from observations of γ-ray bursts. Nature 393, 763– 765 (1998).

    ADS  CAS  Article  Google Scholar 

  30. 30

    Ahluwalia, D. V. Can general relativistic description of gravitation be considered complete? Mod. Phys. Lett. A 13, 1393– 1400 (1998).

    ADS  CAS  Article  Google Scholar 

  31. 31

    Snadden, M. J., McGuirk, J. M., Bouyer, P., Haritos, K. G. & Kasevich, M. A. Measurement of the Earth's gravity gradient with an atom interferometer-based gravity gradiometer. Phys. Rev. Lett. 81, 971–974 (1998).

    ADS  CAS  Article  Google Scholar 

  32. 32

    Service, R. F. Gravity measurements ride the atom wave. Science 281 , 762–763 (1998).

    CAS  Article  Google Scholar 

  33. 33

    Seife, C. Einstein in free fall. New Sci. 158, 11 (1998).

    ADS  Google Scholar 

Download references


I thank A. Ashtekar for suggesting that gravity‐wave interferometers might be useful for experimental tests of some quantum‐gravity phenomena; D. Ahluwalia, J. Ellis, J. Lukierski, N. E. Mavromatos, C. Rovelli, S. Sarkar and J. Stachel for discussions about quantum‐gravity models; and F. Barone, M. Coles, J. Faist, R. Flaminio, L. Gammaitoni, G. Gonzalez, T. Huffman, L. Marrucci and M. Punturo for conversations about experimental interferometry. This work was supported by the Swiss National Science Foundation.

Author information



Corresponding author

Correspondence to Giovanni Amelino-Camelia.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Amelino-Camelia, G. Gravity-wave interferometers as quantum-gravity detectors. Nature 398, 216–218 (1999).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links