Papers by Bahram Mashhoon
The state of a particle in space and time is characterized by its mass and spin, which therefore ... more The state of a particle in space and time is characterized by its mass and spin, which therefore determine the inertial properties of the particle. The coupling of intrinsic spin with rotation is examined and the corresponding inertial effects of intrinsic spin are studied. An experiment to measure directly the spin-rotation coupling via neutron interferometry is analyzed in detail.
Phys Rev D, 2006
The consequences of spin-rotation-gravity coupling are worked out for linear gravitational waves.... more The consequences of spin-rotation-gravity coupling are worked out for linear gravitational waves. The coupling of helicity of the wave with the rotation of a gravitational-wave antenna is investigated and the resulting modifications in the Doppler effect and aberration are pointed out for incident high-frequency gravitational radiation. Extending these results to the case of a gravitomagnetic field via the gravitational Larmor theorem, the rotation of linear polarization of gravitational radiation propagating in the field of a rotating mass is studied. It is shown that in this case the linear polarization state rotates by twice the Skrotskii angle as a consequence of the spin-2 character of linear gravitational waves.
Astrophys J, 1973
ABSTRACT
Physical Review D Particles and Fields, Mar 25, 2009
The analogy between electrodynamics and the translational gauge theory of gravity is employed in ... more The analogy between electrodynamics and the translational gauge theory of gravity is employed in this paper to develop an ansatz for a nonlocal generalization of Einstein's theory of gravitation. Working in the linear approximation, we show that the resulting nonlocal theory is equivalent to general relativity with ``dark matter.'' The nature of the predicted dark matter, which is the manifestation of the nonlocal character of gravity in our model, is briefly discussed. It is demonstrated that this approach can provide a basis for the Tohline-Kuhn treatment of the astrophysical evidence for dark matter.
Astrophys J, 1975
A simple framework based on the concept of quadrupole tidal potential is presented for the calcul... more A simple framework based on the concept of quadrupole tidal potential is presented for the calculation of tidal deformation of an extended test body in a gravitational field. This method is used to study the behavior of an initially faraway nonrotating spherical body that moves close to a Schwarzschild or an extreme Kerr black hole. In general, an extended body moving in an external gravitational field emits gravitational radiation due to its center-of-mass motion, internal tidal deformation, and the coupling between the internal and center-of-mass motions. Estimates are given of the amount of tidal radiation emitted by the body in the gravitational fields considered. The results reported are expected to be of importance in the dynamical evolution of a dense stellar system with a massive black hole in its center.
We briefly discuss the current status of Mach's principle in general relativity and point out tha... more We briefly discuss the current status of Mach's principle in general relativity and point out that its last vestige, namely, the gravitomagnetic field associated with rotation, has recently been measured for the earth in the GP-B experiment. Furthermore, in his analysis of the foundations of Newtonian mechanics, Mach provided an operational definition for inertial mass and pointed out that time and space are conceptually distinct from their operational definitions by means of masses. Mach recognized that this circumstance is due to the lack of any a priori connection between the inertial mass of a body and its Newtonian state in space and time. One possible way to improve upon this situation in classical physics is to associate mass with an extra dimension. Indeed, Einstein's theory of gravitation can be locally embedded in a Ricci-flat 5D manifold such that the 4D energy-momentum tensor appears to originate from the existence of the extra dimension. An outline of such a 5D Machian extension of Einstein's general relativity is presented.
Gen Relativ Gravit, 1984
A new general-relativistic many-body effect is described. It results in an unexpectedly large rel... more A new general-relativistic many-body effect is described. It results in an unexpectedly large relative acceleration between neighboring test particles that follow an inclined orbit about a rotating mass. The effect vanishes if the orbit coincides with the equatorial plane of the rotating mass. The existence of this effect is due to a small divisor involving the deviation of the orbital frequency measured by a comoving clock from the frequency measured by an inertial clock. The influence of the rotation of the sun on the earth-moon system is investigated, and it is shown that the new effect causes a harmonic variation in the earth-moon separation with an amplitude of order 1 m and dominant periods of 18.6 yr, about 0.5 yr, 1 month, and about 0.5 month. The confirmation of these results by the lunar laser-ranging experiment would provide a significant new test of general relativity and a measurement of the angular momentum of the sun.
A new analytic method for the determination of quasinormal oscillations of a black hole is presen... more A new analytic method for the determination of quasinormal oscillations of a black hole is presented. It is based on a connection between the quasinormal modes and the bound states of the inverted black-hole potentials. With use of this method, the quasinormal ...
General Relativity and Gravitation
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Papers by Bahram Mashhoon