Starting from the original experiment performed by Henry Cavendish more than two centuries ago, the precision determination of the gravitational constant G remains a challenging endeavor.
It has been measured about a dozen times over the last 50 years, but the results have varied much more than what would be expected from random and systematic errors. Likely, this is due to the fact that, so far, all the past experiments have relied on macroscopic classical instruments, which could all be governed by uncontrolled mechanical influences. On the other hand, a recent controversial study about correlations between the measured values of G and the variations of the length of day seems to suggest that some other not well-understood effects could be present.
The MEGANTE experiment (ERC-StG-2018 hosted by INFN) will address all these issues by carrying out precision G determinations making use of original experimental strategies based on quantum sensors.
Unprecedented accuracy levels will be achieved using cold atoms in free-fall to probe the gravitational field, surpassing thus the state-of-art measurements based on torsion balance and simple pendulum. In parallel, MEGANTE will provide results that go far beyond the pure metrological interest. Indeed, owing the lack of a full understanding of gravity, several theoretical models predict new physics phenomena such violations of the inverse square law or a dependency of the G value from the local density of the matter.
In the present talk I will present all the scientific and technical challenges that are needed to be faced in order to accomplish all the project goals.