Two-body and Three-body Contacts for Identical Bosons near Unitarity

Understand

In a recent experiment with ultracold trapped Rb-85 atoms, Makotyn et al.

• have studied a quantum-degenerate Bose gas in the unitary limit where its scattering length is infinitely large.
• We show that the observed momentum distributions are compatible with a universal relation that expresses the high-momentum tail in terms of the 2-body and the 3-body contacts.
• We determine the 2- and 3-body contact densities for the unitary Bose gas with number density n to be approximately 20n^{4/3} and 2n^{5/3}, respectively.