This article suggests a new quantum mechanical framework to investigate the relations between space-time and particles. First, we introduce a formal framework to deal with possible worlds, we say potential worlds, independent of interpretations: the quantical modal logic. This framework is compatible but simpler than multiple-world and pilot-wave interpretations and avoids ontological commitments. On this basis, we reformulate virtual particles of QFT as potential particles and, adding a few reasonable hypotheses, we show that Lorentz transformation and Special Relativity (SR) emerge as a Quantum Mechanical phenomenon, unlike Ein-stein's interpretation. This kinetic theory of SR relies mainly on a reformulation of SR without "rods and clocks". We use the same model to derive Newtonian gravitation solely from a gravitational redshift assumption. This theory drives us to suggest the trans-world gravitation hypothesis that the weight might be active between the potential worlds. If this effect is real, we show it to be experimentable with available techniques. Finally, in a speculative part of this article we explore some foreseeable consequences of the trans-world gravitation phenomenon. We suggest that it could contribute explanations for the cosmic inflation, the dark matter and the cosmological constant problem. Moreover, our kinetic theory in an expanding universe might lead to a justification of the MOND theory.