Inertial and gravitational experiments with superfluids: a progress report.

A study is in progress to assess the feasibility of laboratory experiments to detect post-newtonian gravitational fields by looking at the macroscopic quantum phase of superconductors and superfluid 4 He. A novel class of detectors is proposed, together with a discussion of their response to weak deviations from a flat metric. Preliminary experimental results and calculations of expected noise limits are presented.