RE: Detecting nuggets of dark matter

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RE: Detecting nuggets of dark matter

lemouth (72)in #steemstem • 6 years ago

Are there theories that dark matter particles are actually microscopic black holes? Can such theories be considered seriously?

Naively I would have said no, because micro black holes evaporates (and a viable dark matter candidate must be stable). After checking, there is actually one theory that proposes this idea. The research paper is available here. I however haven't read it so that I can't tell.

Primordial black holes are in contrast good candidates to explain dark matter, and this hypothesis could be challenge by the future experiments hunting for gravitational waves.

6 years ago in #steemstem by lemouth (72)

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jent (43) 6 years ago

Aha, primordial black holes then. Aren't they too big for dark matter, which supposedly should be uniformly distributed in the Universe?

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lemouth (72) 6 years ago

Dark matter is not uniformly distributed in t he universe. There are areas where a larger density is needed, and vice versa. The model is pretty constrained, especially since the discovery of gravitational waves, but it is not excluded. And as anything that is not excluded is alive ... :)

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soy-venezuelien (55) 6 years ago (edited)

Will there be any relationship between matter and energy for this case?

Recent developments in string compactifications demonstrate obstructions to the simplest constructions of low energy cosmologies with positive vacuum energy. The existence of obstacles to creating scale-separated de Sitter solutions indicates a UV/IR puzzle for embedding cosmological vacua in a unitary theory of quantum gravity. Motivated by this puzzle, we propose an embedding of positive energy Friedmann-Lemaître-Robertson-Walker cosmology within > string theory. Our proposal involves confining 4D gravity on a brane which mediates the decay from a nonsupersymmetric five-dimensional anti–de Sitter false vacuum to a true vacuum. In this way, it is natural for a 4D observer to experience an effective positive cosmological constant coupled to matter and radiation, avoiding the need for scale separation or a fundamental de Sitter vacuum.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.261301

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lemouth (72) 6 years ago

I am sorry, but I am not sure to understand the question. Dark matter has to account for a significant fraction of the energy budget of the universe, so that I would tend to answer 'yes' to your question.

By the way, the article you are referring to has nothing to do with the topic addressed is this post, as this consists in a string theory model for cosmology.

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