We measure the zero-temperature equation of state of a homogeneous Bose gas of Li7 atoms by analyzing the in situ density distributions of trapped samples. For increasing repulsive interactions our data show a clear departure from mean-field theory and provide a quantitative test of the many-body corrections first predicted in 1957 by Lee, Huang, and Yang [Phys. Rev. 106, 1135 (1957).PHRVAO0031-899X10.1103/PhysRev.106.1135]. We further probe the dynamic response of the Bose gas to a varying interaction strength and compare it to simple theoretical models. We deduce a lower bound for the value of the universal constant ξ>0.44(8) that would characterize the universal Bose gas at the unitary limit.
Physical Review Letters
- Pub Date:
- September 2011
- Ultracold gases trapped gases;
- Boson systems;
- Radio-frequency microwave and infrared spectra;
- Condensed Matter - Quantum Gases