Gravitational wave analogues in spin nematics and cold atoms

Large-scale phenomena, such as gravitational waves, are notoriously difficult to study in a laboratory setting. None the less, parallels with condensed matter systems can provide a way to access equivalent physics at manageable scale. In this talk, we show how spin nematic phases, realised in spinor condensates, can give access to linearised gravity, and in particular that their Goldstone modes are relativistically-dispersing massless spin-2 Bosons, mathematically-equivalent to gravitational waves.

Starting at the level of the action, we first show that the low-energy effective field theory describing a spin nematic is in one-to-one correspondence with that of linearized gravity. We then identify a microscopic, spin-1 model whose low-energy excitations are relativistically dispersing, massless spin-2 Bosons, providing a direct analogue of gravitational waves in a flat spacetime. Finally, with the aid of simulation, we outline a procedure for observing these analogue gravitational waves in a cold gas of 23Na atoms.

These results suggest that spinor condensates could be used to simulate many of the essential features of linearised gravity.