fuzzy dark matter




physics, mathematical physics, philosophy of physics

Surveys, textbooks and lecture notes

theory (physics), model (physics)

experiment, measurement, computable physics

Fields and quanta



A model for dark matter made up of massive but extremely light particles, whose de Broglie wavelength is at the scale of galaxies.

The idea is that on scales above that of galaxies, the predictions of fuzzy dark matter agree with the standard cold dark matter models that work exceptionally well on cosmological scales, while on scales of the size of galaxies the quantum properties of these light particles become relevant and change their effect just so as to fix the problems (see also MOND) that standard cold dark matter models have on these scales.

A natural candidate for such ultra-light particles are axions.

This kind of model was brought up independently by several groups of authors (see Lee 17 for historical survey) with early precursors going back as far as (Baldeschi-Gelmini-Ruffini 83), and accordingly goes by a number of different names, including the following:

and more.

The suggestion that fuzzy dark matter induces the observed almost-flat galactic rotation curves (“MOND”) seems to go back to (Sin 92). Further pointers are in (Lee 17, p. 3):

There are many works explaining the rotation curves of dwarf [17, 23, 69], and large galaxies [29, 43, 70–78] in this model.

More recently, detection of the 21cm hydrogen line from cosmic dawn indicates that star formation set in earlier than compatible with fuzzy dark matter models (Nebrin 17, Nebrin-Ghara-Mellema 18). This would rule out substantial contributions of fuzzy dark matter.


Original articles

Early precursors of the idea include

  • M. R. Baldeschi, G. B. Gelmini, and R. Ruffini, Physics Letters B 122, 221 (1983).

The role of the Bose-Einstein condensate of axions on galactic scales was considered in

The proposal in the guise of “fuzzy dark matter” is originally due to

  • Wayne Hu, Rennan Barkana, Andrei Gruzinov, Cold and Fuzzy Dark Matter, Phys.Rev.Lett. 85 (2000) 1158-1161 (arXiv:astro-ph/0003365)

A detailed discussion is in

Some thoughts on the quantum measurement problem for fuzzy DM particles with huge macroscopic Compton wavelengths? is in

MOND Phenomenology

Discussion of how superfluid aspects of axionic fuzzy dark matter reproduce MOND phenomenology is in

Tension with 21cm hydrogen line

Strong constraints on fuzzy dark matter from observation of the cosmic 21cm hydrogen line are claimed and discussed in

  • Adam Lidz, Lam Hui, The Implications of a Pre-reionization 21 cm Absorption Signal for Fuzzy Dark Matter, Phys. Rev. D 98, 023011 (2018) (arXiv:1805.01253)

  • Olof Nebrin, Cosmic Dawn in a Fuzzy Universe: Constraining the nature of Dark Matterwith 21 cm Cosmology, Stockholm 2017 (diva2:1195402, urn:nbn:se:su:diva-154861)

  • Olof Nebrin, Raghunath Ghara, Garrelt Mellema, Fuzzy Dark Matter at Cosmic Dawn: New 21-cm Constraints (arXiv:1812.09760, reddit)


Review includes

Numerics and experiment

Comparison to experiment (observation) is discussed in

  • Bohua Li, Tanja Rindler-Daller, and Paul R. Shapiro, Cosmological constraints on Bose-Einstein-condensed scalar field dark matter, Phys. Rev. D 89, 083536, 2014 (arXiv:1310.6061)

  • Hsi-Yu Schive, Tzihong Chiueh, Tom Broadhurst, Cosmic structure as the quantum interference of a coherent dark wave, Nature Physics 10, 496–499 (2014) (doi:10.1038/nphys2996)

  • Nilanjan Banik, Adam J. Christopherson, Pierre Sikivie, Elisa Maria Todarello, New astrophysical bounds on ultralight axionlike particles, Phys. Rev. D 95, 043542 (2017) (arXiv:1701.04573)

Claim that the galaxy core-cusp problem is not resolved after all is discussed in

  • Heling Deng, Mark P. Hertzberg, Mohammad Hossein Namjoo, Ali Masoumi, Can Light Dark Matter Solve the Core-Cusp Problem? (arXiv:1804.05921)

Computer simulation of structure formation with fuzzy dark matter:

Last revised on October 3, 2019 at 02:54:19. See the history of this page for a list of all contributions to it.