Universal Relation for the Inelastic Two-Body Loss Rate

Understand

Strongly-interacting systems consisting of particles that interact through a large scattering length satisfy universal relations that relate many of their central properties to the contact, which measures the number of pairs with small separations.

• We use the operator product expansion of quantum field theory to derive the universal relation for the inelastic 2-body loss rate.
• A simple universal relation between the loss rate and the contact is obtained by truncating the expansion after the lowest dimension operator.
• We verify the universal relation explicitly by direct calculations in the low-density limit at nonzero temperature.