At very low temperatures, quantum matter can show radically different, and often counterintuitive, behavior compared to traditional liquids, solids, and gases. Such quantum phases of matter (e.g., superfluids and superconductors) are used in practical applications such as levitating trains and medical imaging. In the field of quantum simulation, researchers are attempting to engineer phases of matter that are even more exotic. One appealing approach is to start with a standard quantum fluid and "drive it" by shaking it, rotating it, or subjecting it to an external field. However, this method faces a serious difficulty: the phase is unstable.
Physicists considering a foray into the study of molecules are often warned that “a diatomic molecule is one atom too many!”. Now John Doyle and colleagues at Harvard University have thrown this caution to the wind and tackled laser cooling of a triatomic molecule with success, opening the door to the study of ultracold polyatomic molecules.
Observation of discrete time-crystalline order in a disordered dipolar many-body system. Nitrogen–vacancy centres (blue spheres) in a nanobeam fabricated from black diamond are illuminated by a focused green laser beam and irradiated by a microwave source. doi:10.1038/nature21426. Reprinted by permission from Macmillan Publishers Ltd: Nature ©2017.
Dr. David Morin's new book, Special Relativity: For the Enthusiastic Beginner, is written for high school and college students learning about special relativity for the first time. It will appeal to the reader who has a healthy level of enthusiasm for understanding how and why the various results of special relativity come about.