Nonlinear Sensing With Collective States of Ultracold Atoms in Optical Lattices.

摘要

The goal of this project was to develop and evaluate methods for nonlinear sensing with collective states of ultracold atoms in optical lattices. Major results include the following: (1) We showed how to use the collapse-and-revival dynamics of interacting atoms to measure m-body interaction strengths with accuracy scaling as n^(m-1/2); m = 1 corresponds to the shot-noise limit. We developed techniques for both m=2 and m=3, the latter exploiting 3-body interactions with super-Heisenberg scaling n^-5/2. (2) We predicted novel spin-dependent 3- body interactions with applications to sensing external magnetic fields. (3) We proposed a method to measure gravitational accelerations (little g) in a very small region of space (e.g., lending itself to atom-chip-based approaches), with potentially long interrogation times. (4) We showed how collapse-and-revival physics can be used to probe Mott insulating and fermionic states. (5) We characterized the effective 3-, 4-, and 5-body interactions between trapped atoms, including universal, effective range, and nonuniversal physics. (6) We developed a dynamical decoupling protocol for removing the influence of 2-body interactions, leaving 3-body interactions dominant. Finally, (7) We characterized Feshbach resonances of magnetic atoms providing results for using spinor atoms to measure magnetic fields accurately.