The internal helicity distinguish particles from antiparticles. Fermions, due to the internal helicity, produce weak jets (they are produced in both the Higgs field composed of non-gravitating tachyons and the luminal Einstein spacetime) that are responsible for the CP (so T as well) violation. Generally, according to the Scale-Symmetric Theory (SST), the weak interactions are along the jets whereas the nuclear strong interactions are in plane perpendicular to the jets. It causes that the nuclear strong interactions are CP (so T as well) invariant - it solves the strong CP problem. Both interactions, due to the thermal motions, can be volumetric. According to SST, there is the two-component spacetime i.e. the Higgs field associated with gravitational fields and the Einstein spacetime associated with the Standard-Model (SM) interactions. To cancel turbulences, there must be produced virtual or/and real particle-antiparticle pairs. But in the gravitational fields, due to their very low density, pairs cannot be produced - it causes that gravity is non-linear and non-linear are phenomena with dominating gravity i.e. phenomena that follow from dynamic viscosity of the non-gravitating tachyons all objects consist of such as friction or motions of the atmosphere of Earth. On the other hand, the quantum mechanics is linear, i.e. superposition and quantum entanglement are linear because in the luminal Einstein spacetime can be produced fermion-antifermion pairs, especially electron-positron pairs. Range of electrons to move in a superconductive manner is equal to the radius of the Bohr orbit in the hydrogen atom - it leads to the threshold for density of bound and free electrons for superconducting materials (about 1.5 kg per cubic meter).