In this invited review in honor of 100 years since the Stern-Gerlach
(SG) experiments, we describe a decade of SG interferometry on the atom
chip. The SG effect has been a paradigm of quantum mechanics throughout
the last century, but there has been surprisingly little evidence that
the original scheme, with freely propagating atoms exposed to gradients
from macroscopic magnets, is a fully coherent quantum process.
Specifically, no full-loop SG interferometer (SGI) has been realized
with the scheme as envisioned decades ago. Furthermore, several
theoretical studies have explained why it is a formidable challenge.
Here we provide a review of our SG experiments over the last decade. We
describe several novel configurations such as that giving rise to the
first SG spatial interference fringes, and the first full-loop SGI
realization. These devices are based on highly accurate magnetic fields,
originating from an atom chip, that ensure coherent operation within
strict constraints described by previous theoretical analyses. Achieving
this high level of control over magnetic gradients is expected to
facilitate technological applications such as probing of surfaces and
currents, as well as metrology. Fundamental applications include the
probing of the foundations of quantum theory, gravity, and the interface
of quantum mechanics and gravity. We end with an outlook describing
possible future experiments.
|Original language||English GB|
|State||Published - 1 Sep 2020|