Gyroscope deviation from geodesic motion: quasiresonant oscillations on a circular orbit

General relativistic spin-orbit interaction leads to the quasiresonant oscillation of the gyroscope mass center along the orbital normal. The beating amplitude does not include the speed of light and equals the ratio of the intrinsic momentum of the gyroscope to its orbital momentum. The modulation frequency equals the angular velocity of the geodetic precession that prevents the oscillation from resonance. The oscillation represents the precession of the gyroscope orbital momentum. Within an acceptable time the oscillation amplitude reaches the values that are amenable to being analyzed experimentally. Taking into account the source oblateness decreases the beating amplitude and increases the modulation frequency by the factor that is equal to the ratio of the quadrupole precession velocity to the geodetic precession velocity. The period of the quadrupole precession turns out to be a quite sufficient time to form a measurable amplitude of the oscillation.Comment: 5 pages, LaTeX2e, 1 eps figure, to appear in J. Exp. Theor. Phy

Magnetic moment of the two-particle bound state in quantum electrodynamics

We have formulated the quasipotential method for the calculation of the relativistic and radiative corrections to the magnetic moment of the two-particle bound state in the case of particles with arbitrary spin. It is shown that the g-factors of bound particles contain $O(\alpha^2)$ terms depending on the particle spin. Numerical values for the g-factors of the electron in the hydrogen atom and deuterium are obtained.Comment: Talk presented at Nuclear Physics Department Conference "Physics of Fundamental Interactions" Russian Academy of Sciences, ITEP, Moscow, 27 November-1 December 2000. 11 pages, 1 figure uses linedraw.st

Equations of Motion of Spinning Relativistic Particle in External Fields

We consider the motion of a spinning relativistic particle in external electromagnetic and gravitational fields, to first order in the external field, but to an arbitrary order in spin. The correct account for the spin influence on the particle trajectory is obtained with the noncovariant description of spin. Concrete calculations are performed up to second order in spin included. A simple derivation is presented for the gravitational spin-orbit and spin-spin interactions of a relativistic particle. We discuss the gravimagnetic moment (GM), a specific spin effect in general relativity. It is demonstrated that for the Kerr black hole the gravimagnetic ratio, i.e., the coefficient at the GM, equals to unity (as well as for the charged Kerr hole the gyromagnetic ratio equals to two). The equations of motion obtained for relativistic spinning particle in external gravitational field differ essentially from the Papapetrou equations.Comment: 22 pages, latex, no figure