Call it Aether, pilot wave, vacuum energy, and lately dark matter and dark energy, what they all are leading to is that we have real and imaginary spacetime and energy within it.
But it goes further than that, you have layers of an onion 2D, 4D, 8D, etc that are what is call quantum spin, each layer must have both real and imaginary, positive and negative quarters, as this is the rules defined by using complex numbers, ℝ,ℂ,ℍ,𝕆,𝕊 etc as defined by Cayley-Dickson construction.
Pilot wave (and Aether before it) would be best described as dark matter today. 4D rotational mapping (gravity) to reality or ℍ => 𝕆
Reality forms when particles have shared past, it can only be surrounded by other realities that have equal size/shape (4D Quaternion), but are imaginary rotated (dark/space-like) to us.
The blue central box shown is time, if talking ℝ => ℂ => ℍ the red/blue is spacetime of the electron and positron, and electromagnetism, the two parallel universes as it were, the green/cyan would be the spacetime for quarks, 3D red, green and blue colours.
But for ℍ => 𝕆, the red/blue is not matter and antimatter reality, and cyan/green dark matter and dark antimatter reality. They still have either shared past or shared future and must be separated by event horizons or light-like infinities. These could be either light-like and real as in black holes or vacuum-like and imaginary as in big bangs.
AKA what we think of as realities are ring groups of dimensions, held together or defined by the energy within it. AKA is we are 4D atoms, we see spacetime as 4D, and particles and thus quantum mechanics, etc as smaller (probabilistic because we can't see it at all times as it can be both real or virtual/imaginary based on wave function - aka the whole point of particle and wave duality). 4D to 4D we can see/measure all movement and its deterministic. 4D to 8D and higher and it then becomes non associative - like dark matter.
This is because of the rules of complex numbers, quantum mechanics is probabilistic as it is commutative, time reversal is possible, quaternion spacetime loses that, so special relativity and higher must lose that, worse still general relativity is talking of 8D physics, 4D curvature from quaternion to octonion and octonions lose associativity, commonly this is called the information paradox - as information is lost when it crosses the event horizon of a black hole, or asking questions like what came before big bang - that information is completely dis-associated from us, aka dark.
BUT if you think in terms of rotation, be they 2D, 4D, etc you can infer what they must have been relative to us.