It is pointed out that the coupling of macroscopic test masses to the gravi-dilaton background of string theory is non geodesic, in general, and cannot be parametrized by a Brans-Dicke model of scalar-tensor gravity. The response of gravitational antennas to dilatonic waves should be analyzed through a generalized equation of geodesic deviation, taking into account the possible direct coupling ...

The detection of stochastic gravitational wave background (SGWB) is among the leading scientific goals space-borne observatory, which would have significant impact on astrophysics and fundamental physics. In this work, we developed a data analysis software, \texttt{TQSGWB}, can extract isotropic SGWB using Bayes method based TianQin detector. We find that for noise cross spectrum, there are ima...

Neutron stars are perhaps the most promising class of gravitational wave (GW) sources, and searches for such GW signals is particularly suited to the characteristics of the GEO600 detector (see Schutz “Getting Ready for GEO600 Data” gr–qc9910033). However, the instantaneous GW frequency of such a source will evolve due to both intrinsic spindown effects and Doppler modulations induced by the mo...

Critically coupled resonant optical cavities are often used as mode cleaners in optical systems to improve the signal-to-noise ratio (SNR) of a signal that is encoded as an amplitude modulation of a laser beam. Achieving the best SNR requires maintaining the alignment of the mode cleaner relative to the laser beam on which the signal is encoded. An automatic alignment system that is primarily s...

Beam alignment is an important practical aspect of the application of squeezed states of light. Misalignments in the detection of squeezed light result in a reduction of the observable squeezing level. In the case of squeezed vacuum fields that contain only very few photons, special measures must be taken in order to sense and control the alignment of the essentially dark beam. The GEO 600 grav...