> Zum Inhalt


Univ. Prof. Dr. Hartmut Abele

Tel.: +43-1-58801-141202   
Fax: +43-1-58801-14199 

TU Wien - Atominstitut
Stadionallee 2
1020 Vienna





Test of Gravitation with Quantum Interference

The qBounce experiment tests gravity tests at small distances with quantum interference techniques.


Quantum objects so far provide the most precise measuring techniques. Examples are atomic clocks or magnetic resonance techniques, which deliver accurate time standards or fanciful images of the body at the doctor’s office for medical services.


We adapt these techniques to ultra-cold neutrons – within the qBounce experiment - in order to find answers to the most urgent problems of space, time, and cosmology: what is the content of dark matter, an unknown form of mass, which is responsible for the major mass contribution in the universe, or what is dark energy, which is responsible for the accelerated expansion of the universe.

Neutron Mirror


The experimental tool is a gravitationally interacting quantum system – a neutron in the gravity potential of the earth and a reflecting mirror - using our new techniques of resonance spectroscopy. Dark matter or dark energy particles interacting with an ultra-cold neutron would become visible by changing its quantum mechanical energy levels in the gravity field in a way similar to a gravitational force.


A hypothetical dark energy field, if it exists, would not only shift the neutron’s gravitational energy levels but would ultimately also drive the universe as a whole apart. The qBounce experiment provides a completely new opportunity to either find additional hypothetical forces and fields similar to gravitation, or to exclude their existence with certainty. Modelled in analogy to magnetic resonance spectroscopy (MRS), the technique is named gravitational resonance spectroscopy (GRS), which was developed in a previous project. But the new technique does not depend on electromagnetism or any interaction to an electrical potential. 


Energy eigenvalues and eigenfunctions of a neutron

bound in the gravity potential of the Earth and corresponding

frequency equivalents.


The team at TU Wien is working on an analysis of the Standard Model of Particle Physics and Gravitation at small distances, where the neutron is the object. At the beginning, we provided an analysis of several candidates, which effectively induce a deviation of Newton’s gravity law at short distances. Some candidates like the so called axion are also dark matter candidates, others, like the chameleon or symmetron fields, might be responsible for the expansion of the universe. The team at the Institut Laue-Langevin (ILL) is providing the most intense neutron source of ultra-cold neutrons and, at no other place this experiment can be executed. Regarding the theoretical part, a universal look at gravitation is established, which goes far beyond the gravity theory of Einstein.




[Ade09] E.G. Adelberger et. al., Prog. Part. Nucl. Phys 62, 102 (2009).

[Ark99] N. Arkani-Hamed, S. Dimopolos, G. Dvali, Phys. Rev. D59, 086004 (1999).

[Bra11] P.Brax, G.Pignol, Phys. Rev.Lett. 107, 111301(2011).

[Chai12] M. Chaichian, M. Oksanen, A. Tureanu, On entrotic gravity …, Physics Letters B 712 272 (2012).

[Fis92] E. Fischbach and C. Talmadge, Nature 356, 207 (1992).

[Joh03] C.V. Jonson, in D-Branes, Cambridge University Press (2003).

[Kho04a] J. Khoury and A. Weltman, Phys. Rev. Lett. 93, 171104 (2004).

[Kho04b] J. Khoury and A. Weltman, Phys. Rev. D69, 044026 (2004).

[Kob11] A. Kobakhidze, once more: gravity is not an entropic force, arXiv:1108.4161.

[Moo84] J.E. Moody and F. Wilczek, Phys. Rev. D30, 130 (1984).

[Mot07a] D.F.Mota and D.J. Shaw, Phys. Rev. D75, 063501 (2007).

[Mot07b] D.F.Mota and D.J. Shaw, Phys. Lett. 97, 151102 (2007).

[PDG10] K. Nakamura et al(Particle Data Group), J. Phys. G37, 075021 (2010).

[Pre78] R.D. Peccei and H. Quinn, Phys. Rev. Lett. 38, 1440 (1977); Phys. Rev. D16, 1791 (1978).

[Ram08] M.J. Ramsey-Musolf and S.Su, Physics Reports 456, 1 (2008).

[Ran99] L. Randall and R. Sundrum, Phys. Rev. Lett. 83, 4922 (1999).

[Str01] A. Strominger and C. Vafa, Phys. Lett. B379, 99 (1996); C. V. Johnson, in D-Brane primer,
In TASI 1999, Strings, Branes and Gravity, World Scientific, (2001).

[Ver11] E. Verlinde, On the origin of gravity and the laws of Newton, arXiv:10001.0785

[Wei78] S. Weinberg, Phys. Rev. Lett 40, 223 (1978).

[Wil78] F. Wilczek, Phys. Lett. 40, 279 (1978). [You96] A.N. Youndin et al., Phys. Rev. Lett. 77, 2170 (1996).


[1] T. Jenke, P. Geltenbort, H. Lemmel, Hartmut Abele, Realization of a gravity resonance spectroscopy method, Nature Physics 7 468 (2011).