Vacuum energy and dark matter Vacuum energy can only be measured indirect. It is often discussed in the context of dark energy. The cosmological constant can be written as vacuum energy and vacuum pressure in the stress-energy-momentum-tensor.
Another dark (unknown) parameter in our universe is dark matter.
Have there been attempts to assign the dark matter to the energy density of the vacuum?
A negative energy density of the vacuum would be an interesting candidate for an alternative explanation for dark matter:

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*instead of adding unknown matter it would be possible to take away space.

 A: The fact that both substances are named "dark" is just a reflection of our ignorance about them. Mathematically they have very different properties.
Dark matter, on the one side, is just like normal matter in many aspects. It is subject to gravity as normal matter and also dilutes with the expansion of spacetime. Its density falls as $a^{-3}$, where $a$ is the scale factor.
Dark energy, on the other hand, must not dilute, it is constant energy. That is, it does not scale with $a$. So the vacuum energy if related to dark energy cannot be explained by dark matter.
One cannot explain the other because we know how they scale and they do not match, they appear to be very different types of components.
A: Dark energy is the outflow of dark matter along the pole of our universe's central black hole.
Our visible universe is in the outflow of our universe's central black hole. As ordinary matter falls toward the central black hole it evaporates into dark matter. It is the dark matter outflow which pushes the galaxy clusters, causing them to move outward and away from us. The dark matter outflow is dark energy.
As ordinary matter falls toward our Universe's central black hole it evaporates into dark matter and is emitted along the poles. The pressure is so great that some of the dark matter condenses back into particles of ordinary matter. Over time, the particles form more complex structures, eventually leading to the creation of galaxies and galaxy clusters. The dark matter outflow pushes the galaxy clusters outward and away from us.
The galaxy clusters which have been pushed for longer than we have are accelerating outward and away from us. We are accelerating outward and away from the galaxy clusters which have been pushed for less time than we have. From our perspective most of the galaxy clusters are accelerating away from us.
You toss a bunch of ping pong balls into a fast flowing stream. As long as the stream is flowing faster than the ping pong balls the ping pong balls are going to accelerate. As the ping pong balls empty into a lake, again, as long as the stream is flowing faster than the ping pong balls, the ping pong balls are going to continue to accelerate as they move outward and away from one another.
In the analogy, the fast flowing stream emptying into the lake is dark energy, the water is dark matter and the ping pong balls are the galaxy clusters. The ping pong balls displace the water. The water pushing back and exerting pressure toward the ping pong balls is gravity.
