Abstract: We find a fast non-adiabatic protocol for the creation of spin squeezed ground states in a spin-1 Bose condensate and experimentally generate those states near the quantum critical point between the polar and ferromagnetic quantum phases of the interacting spin ensemble. The method consists of a pair of controlled quenches of an external magnetic field, which has the same leading order dependence for the total time as the quantum optimal control method but is simpler and realizable. In contrast to typical non-equilibrium methods for preparing atomic squeezed states by quenching through a quantum phase transition, squeezed ground states are time-stationary and remain squeezed for the lifetime of the condensate. A squeezed ground state with a metrological improvement up to 6-8 dB and a constant squeezing angle maintained over 2s is demonstrated.
Biography: Lin Xin is a graduate student at Georgia Tech, School of Physics, working in Prof. Michael Chapman's Bose-Einstein condensation (BEC) laboratory. His research focuses on many-body interaction in ultracold atoms. He received his B.S. in physics with the highest honors from Shanghai Jiaotong University in 2016, where he worked on theoretical ultrafast AMO physics.
Host: Ian Spielman