abstract

An electromagnetic wave propagating in the toroidal waveguide is considered as an electromagnetic gravitational antenna. An interferometric method is applied to measure the disturbances of phase of the electromagnetic field caused by the incident gravitational wave. The calculations presented take into account the dispersive and dissipative phenomena occurring during the interaction between electromagnetic and gravitational fields. The active cross-section of the antenna interacting with coherent and pulsed gravitational radiation is estimated. Experimental possibilities presently available are discussed. Limiting fluxes in the astrophysical range of frequencies measured by the interferometric electromagnetic antenna are a factor of ten or so smaller than in the case of a classic mechanical antenna. Moreover the antenna could be used for carrying out a gravitational Hertz experiment.

abstract

It is shown, by a different method than used originally, that the gauge theory proposed by Ferraris and Kijowski is an interacting gravitational and electromagnetic fields theory. Using a new method, the affine Lagrangians of the linear Maxwell–Einstein and of the Born–Infeld–Einstein electrodynamics are derived. Two theorems relating the affine and the matter Lagrangians for the electromagnetic field are proved.

abstract

The state of hadron spectroscopy in general and of heavy quark-antiquark bound states in particular is briefly reviewed. The first lecture is devoted to a summary of elementary techniques of quarkonium quantum mechanics. The second is concerned with inverse-scattering techniques. Throughout, the implications of recent data are assessed.