A clock based on just a single atom — the simplest clock yet — has now been devised, researchers say. This new device to measure time could help lead to a radically new way to define mass as well, ...

These days, everybody learns in grade school that an atom looks a bit like a little solar system, with a positively charged nucleus orbited by negatively charged electrons. Hydrogen is the simplest ...

In the quantum world, making the simple atom behave is one thing, but making the more complex molecule behave is another story. Now scientists have figured out an elegant way to stop a molecule from ...

A quantum dot is usually charged by inserting electrons. But electrons can also be removed from a neutral dot. Unexpectedly, positively charged dots are different from highly charged negative ones, ...