Best of Last Week – Creating negative mass, a recipe for starting life on Earth and fast food's impact on immune system

In this optical microcavity, created by the lab

of Nick Vamivakas, confined light interacts with an atomically thin semiconductor to create particles with negative mass. The device also presents “a way to generate laser light with an incrementally small amount of power,” says Vamivakas, an associate professor of quantum optics and quantum physics at Rochester’s Institute of Optics. Credit: Michael Osadciw/University of Rochester

It was another good week for physics, as a team at the University of Rochester announced that they had created a device that creates negative mass, and along with it, a novel way to generate lasers. Their device works in atomically thin semiconductors with confined light. Also, an international team of physicists announced that they had created the first direct images of the square of the wave function of a hydrogen molecule—which allowed for visually imaging entanglement between electrons. And a team with members from the U.S. and Israel demonstrated an example of accelerating light beams in curved space—by shining a laser along the inside shell of an incandescent light bulb. Also, a team working at the U.S. DOE's Brookhaven National Laboratory reported on surprising results they found when studying spin. They observed an unexpected skew when studying spinning protons colliding with protons of different sizes.