  We study possibilities of creation and detection of oscillating gravitational
fields from lab-scale high energy, relativistic sources. The sources considered
are high energy laser beams in an optical cavity and the ultra-relativistic
proton bunches circulating in the beam of the Large Hadron Collider (LHC) at
CERN. These sources allow for signal frequencies much higher and far narrower
in bandwidth than what most celestial sources produce. In addition, by
modulating the beams, one can adjust the source frequency over a very broad
range, from Hz to GHz. The gravitational field of these sources and responses
of a variety of detectors are analyzed. We optimize a mechanical oscillator
such as a pendulum or torsion balance as detector and find parameter regimes
such that -- combined with the planned high-luminosity upgrade of the LHC as a
source -- a signal-to-noise ratio substantially larger than 1 should be
achievable at least in principle, neglecting all sources of technical noise.
This opens new perspectives of studying general relativistic effects and
possibly quantum-gravitational effects with ultra-relativistic, well-controlled
terrestrial sources.
