General Relativity and Gravitation, VoL 15, No. 8, 1983 Remote Quantum Mechanical Detection of Gravitational Radiation T. K. LEEN, LEONARD PARKER, and LUIS O. PIMENTEL Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201 Received May 25, 1982; Revised February 11, 1983 Abstract The presumed existence of atomic hydrogen in the vicinity of sources of gravitational radia- tion suggests its use as a radiation detector. Curvature-induced atomic energy level shifts carry a unique signature and could thus provide for remote detection of gravitational radia- tion. We investigate the shifts induced by space-time curvature arising from gravitational waves. The effect is studied for both low-lying and highly excited states of atomic hydrogen. Numerical results are quoted for radiation from various sources, including binary star sys- tems, binary neutron stars, binary black holes, collapsing stars, and pulsars. In addition, we provide a theoretical upper limit to the magnitude of the effect. For completeness, we ex- amine the shifts induced in a harmonic oscillator as well as a rigid rotator. w Introduction It is well recognized that the detection of gravitational radiation would provide a unique window on astrophysical phenomena since in contrast to electromagnetic and neutrino radiation, gravitational waves are emitted by coherent bulk motions of matter. In addition, the fact that such radiation is most strongly emitted by relativistic sources provides impetus for studying such waves as a means of testing general relativity (as well as competing theories of gravitation). This circumstance has prompted a flurry of activity in gravitational wave astronomy, beginning most notably with the work of Joseph Weber [I ]. Nearly all experimental suggestions thus far have been concerned with the effects of waves reaching the earth, and the development of terrestrial detectors (however, see Ref. 2 for exceptions). The strength of the metric perturbation, buy, reaching an earthbound detector is of course limited by the distance to the 761 0001-7701 / 83/0800-0761 $03.00/0 9 1983 Plenum Publishing Corporation