The title of this article states "quantum particles tunnel through solid barriers". Don't know a lot about this stuff but a magnetic field does not strike me as being a "solid barrier". Actually it sounds like a pretty weak barrier by comparison.
Uranium foil with the same thickness as the mag field would certainly be a "solid" barrier with its electron density. But perhaps the experiment would not work with a more defined solid barrier.
One might assume that the tunneling needs a little help to actually measure, and it could not be done with a truly solid barrier, but a mag. field suits the purpose? Very curious to those of us not familiar with this behavior.
At least the data seems to rule out "voodoo physics", like mentioned in the article :
"While the laws of quantum mechanics allow for quantum tunneling, researchers still don't know exactly what happens while a subatomic particle is undergoing the tunneling process. Indeed, some researchers thought that the particle appears instantaneously on the other side of the barrier as if it instantaneously teleported there..."
It always seemed this aspect of quantum tunneling was a little suspicious......
And rubidium atoms are not subatomic particles, so how does this represent "quantum tunneling"? Perhaps it is a proxy experiment that works with atoms and SPs.