Superluminal motion (review)

Abstract

Prior to the development of Special Relativity, no restrictions were imposed on the velocity of the motion of particles and material bodies, as well as on energy transfer and signal propagation. At the end of the 19th century and the beginning of the 20th century, it was shown that a charge that moves at a velocity faster than the speed of light in an optical medium, in particular, in vacuum, gives rise to impact radiation, which later was termed the Vavilov-Cherenkov radiation. Shortly after the development of Special Relativity, some researchers considered the possibility of superluminal motion. In 1923, the Soviet physicist L.Ya. Strum sug gested the existence of tachyons, which, however, have not been discovered yet. Superluminal motions can occur only for images, e.g., for so called "light spots," which were considered in 1972 by V.L. Ginzburg and B.M. Bolotovskii. These spots can move with a superluminal phase velocity but are incapable of transferring energy and information. Nevertheless, these light spots may induce quite real generation of microwave radi ation in closed waveguides and create the Vavilov-Cherenkov radiation in vacuum. In this work, we consider various paradoxes, illusions, and artifacts associated with superluminal motion.

Hyperbolic Superluminal Scator Algebra

“…The restricted and super-restricted sets are matched with the subluminal and superluminal frames, or to bradyon and tachyon particles respectively. The present interpretation is then in accordance with the now common description of Recami [18] and others [19]. With respect to the composition of orthogonal velocities, our interpretation is that tachyons or bradyons are seen as such regardless of the frame velocity in a perpendicular direction provided it is not in the null geodesic.…”

Transient Cherenkov radiation from an inhomogeneous string excited by an ultrashort laser pulse at superluminal velocity

“…The problem of superluminal motion and its existence in nature attracts attention of various researchers for rather long time. At the turn of XIX-XX centuries, O. Heaviside and A. Sommerfeld considered radiation of charged particles moving in vacuum at the velocity greater than the velocity of light in vacuum c (see [1][2][3][4][5][6][7][8][9][10] and references therein). However, their works were forgotten for many years because the special theory of relativity "bans" such motions.…”

Polarization nonreciprocity suppression of dual-polarization fiber-optic gyroscope under temperature variation

“…Different from the polarization-maintaining scheme with its single-polarization operation, the optical compensation scheme allows two orthogonal polarizations to propagate simultaneously. Actually, the benefit of using two polarizations has been discussed in some early studies [12][13][14][15][16]. Our recent theoretical and experimental findings further indicate that PN errors of two polarizations possess opposite signs, thus they can be optically canceled out when two polarizations are balanced in their intensity.…”