Nature of dark matter

Determine the fundamental nature, composition, and interaction properties of dark matter that account for astrophysical and cosmological observations incompatible with general relativity and known standard-model matter.

Background

Despite the success of GR and quantum theory, multiple astrophysical observations—such as galactic rotation curves and gravitational lensing—cannot be explained by visible matter alone, motivating the postulation of dark matter.

The author explicitly lists dark matter as one of the two biggest open observational problems, noting its typical treatment outside quantum gravity but acknowledging its potential relevance to guiding or confirming QG approaches.

References

Nevertheless, there are some open problems related to observations. The two biggest ones are the problems of dark matter and dark energy.

— Why Do We Want a Theory of Quantum Gravity?  (2505.04858 - Crowther, 7 May 2025) in Section 1.3 (Empirical constraints), Empirical results not explained by current theories

The nature of dark matter remains an open question in fundamental physics, with extensive direct, indirect and collider searches all returning null results.

— QUEST-DMC: Background Modelling and Resulting Heat Deposit for a Superfluid Helium-3 Bolometer  (2402.00181 - Autti et al., 2024) in Section 1 (Introduction)

The origin of neutrino masses and the nature of dark matter constitute, at present, the two main open questions in our understanding of the Universe.

— Effects of Neutrino-Ultralight Dark Matter Interaction on the Cosmic Neutrino Background  (2406.01682 - Martínez-Miravé et al., 2024) in Section 1, Introduction (first paragraph), p. 1

We are investigating whether the second vielbein-like field of CG, the gauge field associated with the special-conformal generators, can play this role once the scalars responsible for the SSB are promoted from auxiliary to dynamical fields .

— Unification of Gravity with Internal Interactions: the SO(2,16) Scheme Revisited  (2608.24165 - Stefas et al., 25 Aug 2026) in Section 5, Conclusions

Such energy injection may arise from exotic processes such as decaying dark matter or primordial black holes, whose physical nature remains to be probed.

— Constraining primordial non-Gaussianity and energy injection with the thermal Sunyaev-Zeldovich effect and integrated Sachs-Wolfe effect cross-correlation  (2608.25809 - Ibitoye et al., 26 Aug 2026) in Section 3, Results and Discussion