According to his idea, outlined in the current issue of the journal Astrophysics and Space Science, matter has a positive gravitational charge and antimatter a negative one.

Therefore, electrons cannot be pictured as localized particles in space but rather should be thought of as" clouds" of negative charge spread out over the entire orbit.

Analytical expressions of coupling frequencies of Raman free-electron lasers are deduced based on the physical image of the coupling between negative-energy space-charge wave and EM wave.