In one minute

Carlos Barceló, S. Liberati and Matt Visser ask how far Bose-Einstein condensates can go in producing a generic effective metric that mimics the kinematics of general relativity. They use a very general nonlinear Schrödinger equation with a position-dependent tensor mass and arbitrary nonlinearity. At low momenta, phase excitations of the condensate obey a d'Alembertian equation for a generic Lorentzian effective metric in 3+1 dimensions set by the background field. At high momenta the eikonal approximation gives a Bogoliubov-like dispersion relation and recovers non-relativistic Newtonian physics. The effective metric appears generically unless interatomic forces are attractive, making condensates an extremely promising system for probing the kinematics of general relativity.

Analogue gravity from Bose-Einstein condensates