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The Special Relativity allows the possibility of a class of particles, knowntachyons, that have spacelike 4-velocities, i.e., which move with velocitygreater than speed of light in vacuum. In this existence frame, the tachyonshave energy and momentum and they must contribute to the gravitational fieldthrough by the means of the energy-momentum tensor. The superluminal perfectfluid tensor is obtained assuming the framework Lagrangian formalism andspacelike 4-velocities flowlines of tachyons with energy density. The perfectfluid of tachyons gives rise a positive energy density and a form of negativepressure, which according to various cosmological theoretical results, it isassociated with dark energy.

The congruence of spacelike curves of tachyons with respective energy-momentum tensor of perfect fluid type