Shortcuts to adiabaticity for trapped ultracold gases

TL;DR

This paper demonstrates experimentally and theoretically how to rapidly and precisely transfer ultracold gases between quantum states using shortcuts to adiabaticity, avoiding slow adiabatic processes.

Contribution

It introduces a method based on invariants of motion and scaling equations for fast, controlled state transfer in ultracold gases, applicable to non-equilibrium states.

Findings

Successful experimental demonstration of fast decompression and displacement.

Final states match those of slow adiabatic transformations.

Method applicable to various trap deformations and initial states.

Abstract

We study, experimentally and theoretically, the controlled transfer of harmonically trapped ultracold gases between different quantum states. In particular we experimentally demonstrate a fast decompression and displacement of both a non-interacting gas and an interacting Bose-Einstein condensate which are initially at equilibrium. The decompression parameters are engineered such that the final state is identical to that obtained after a perfectly adiabatic transformation despite the fact that the fast decompression is performed in the strongly non-adiabatic regime. During the transfer the atomic sample goes through strongly out-of-equilibrium states while the external confinement is modified until the system reaches the desired stationary state. The scheme is theoretically based on the invariants of motion and scaling equations techniques and can be generalized to decompression trajectories including an arbitrary deformation of the trap. It is also directly applicable to arbitrary initial non-equilibrium states.