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The interest surrounding gravitational waves has grown. The current search for gravitational wave entails studying and solving statistical issues, related to the potential sources that ground-based antennas are sensitive to. The case we will address is the status of the data analysis for LIGO I. The techniques for identifying gravitational wave signals depend on both the kind of source that is being searched and also on the characteristics of the detector. This is due to the fact that events which might be analysed as possible candidates, can be artifacts the detector responds to, in a similar way it would do if excited by an astrophysical signal. For example the detector response itself is monitored by calibration lines, that are injected in order to analyse the data according to the characteristic behaviour of the detector. After reviewing the status of the LIGO I interferometers, we will describe the different analyses applied to the data collected during the first scientific data run, aimed to search for a variety of astrophysical events.

Given the scientific potential of established and evolving quantum technologies and the new proposed detector for gravitational wave astronomy MIGO (Matter-wave Gravitational Wave Observatory) it is timely and beneficial to characterize some "actual" prototype and gather important in-depth knowledge in atom interferometry.

Of first and foremost importance is distinguishing the interferometric approach of real space detectors (based on an apparatus layout whose elements are massive optics or diffraction gratings that fix the ends of the interferometer arms) and the inertial sensors based on a superposition of atomic states, where no arm end is assigned by any optics, but rather the superposition starts and ends at given times meanwhile accruing a relative phase between the different momentum states.

The studies presented at the VII Symposium on Frequency Standards and Metrology aim at identifying the potential and sensitivity limits of atom interferometers, based on demonstrated concepts. Their sensitivity is determined by the competition between the signal induced by various disturbances versus that induced by the external fields of interest; the effects depend on the configuration, since different schemes respond differently to the same excitations.

The result is a feasibility exploration that demonstrates the actual capability of operating systems. It identifies both the properties and limitations that are characteristic of atom interferometers. The behaviour of such systems must be fully understood in order to have a basis for the development of the next generation of atom interferometers, as detectors applicable in tests of general relativity and as sensors of gravitational waves.