TESTING GRAVITY IN LARGE EXTRA DIMENSIONS USING BOSE–EINSTEIN CONDENSATES

Recent conjectures that there are mesoscopically "large" extra dimensions, through which gravity propagates have interesting implications for much of physics. The scenario implies gross departures from Newton's law of gravity at small length scales. Testing departures from Coulomb's law on sub-millimetre scales is hard. It is now possible to routinely create Bose–Einstein condensates with de Broglie wavelengths of order a μm and total size of order 10 μm. BEC condensates move coherently under gravitational acceleration, and I propose that the transverse fringe shift due to the acceleration of a pair of interfering BECs passing a dense linear mass may be measurable, and provide direct evidence for anomalous gravitational acceleration. Ideally such experiments are best carried out in free fall to maximise the time spent by a BEC in the non-Newtonian regime.