lol
"not the apparatus used in the latest research"
Editor was all, "I don't care. Put a sciency picture on this article, dammit!"
***
They're saying that it's the inertial mass that is negative (no mention of gravitational mass). They're not saying any known laws of physics need revision.
So F = ma, still. (bold letters used to indicate vectors)
F doesn't change, a doesn't change, only the sign of m changes. The result is that the applied force causes acceleration in the opposite direction of the force.
Meaning that if I push something with negative mass, it will move toward me, not away from me, as expected.
They're not saying any single particle behaves this way. They're saying there is a region of the Bose-Einstion Condensate which behaves in this way.
It sounds like it's a property of the system, and not of the particles.
This still needs peer review and replication as far as I can tell.