Superfluid vacuum theory or SVT is an approach to quantum mechanics and an attempt at a quantum theory of gravity. In this approach, the vacuum or non-removable background is viewed as a superfluid. Another way to understand this vacuum is as a Bose-Einstein condensate. Bose-Einstein condensates are a state of matter. It is a gas of bosons cooled to temperatures very close to absolute zero.
The way SVT is a model of quantum gravity is by modeling all interactions as different manifestations of the superfluid vacuum.
There have been several different papers published related to Superfluid vacuum theory. The only differences are in the properties of background superfluid.
History
The concept of the luminiferous ether was discarded, as a means of a place for the propagation of electromagnetic waves, with the advent of special relativity. Special relativity and a lumiferous ether would lead to some contradictions.
Paul Dirac
As early as 1951, Paul Dirac published 2 papers where he delcares that we should take into account some quantum fluctuations in the ether.
Dirac considered the application of the Heisenberg Uncertainty principle to the velocity of the aether at any particualr moment. Velocity would not be a well defined quantity. It will be distributed over various possible values.
One could understand the aether by a wave function, representing the perfect vacuum state for which all aether velocities are equally probable.
E. C. G. Sudarshan
In 1975, inspired by the ideas of Paul Dirac: K. P. Sinha, C. Sivaram and E. C. G. Sudarshan will propose that the aether could be understood as a superfluid state of fermion and anti-fermion pairs.
This would be describable by a macroscopic wave function.