Cold atoms from few-body physics: Application of Pionless EFT

Strongly interacting atoms are one example of systems interacting through a large scattering length. They display therefore similar features to nuclear systems but are more easily accessible and controllable in experiments. These system can be studied by using so called Pionless EFT. However, understudying this system is challenged by this nonperturbative nature of the interaction. Having universal relations that are valid to various states of the system are therefore very valuable. In this talk I would like to discuss those universal relations and show that the Operator Product Expansion with the EFT that is a powerful tool to derive these relations. I also discuss recently measured unitary Bose gas and show an excellent agreement between the measurement and prediction by the universal relation.