Zero point energy

Zero point energy is the lowest possible amount of energy that a quantum mechanical system can have. This is different than in classical physics. This is because, in quantum mechanics, even in lowest energy states, there are fluctuations. This is described by the Heisenberg uncertainty principle. Atoms, molecules and the vacuum of space all have these properties. In fact, the universe, in quantum mechanics, can be thought of as a series of these continually fluctuating fields. This would be opposed to a series of isolated particles. There are even matter fields. The quanta of these matter fields are the fermions, such as the quarks and leptons. The quanta of these force fields are the bosons, such as the gluon, photon, W and Z. All of these fields have zero point energy. This fluctuating zero energy field will give rise to  kind of reintroduction of the notion of the aether in physics. Some systems can detect the existence of this energy. However, this aether could not be a physical medium, since, Lorentz invariance and special relativity can not be violated. 

There is currently no full theoretical model at the present to understand zero point energy. This discrepancy between theorized and observed vacuum energy has been a serious source of conversation.