Keeping an "ion" the time

A single aluminum ion is at the ticking heart of a new optical clock that is twice as accurate as any other. Hypothetically, the clock would still be accurate to the second in 3.7 billion years time, beating the previous record of 1.7 billion years by more than a few ticks. James Chin-wen Chou, David Wineland and colleagues at the National Institute of Standards and Technology (NIST) in Colorado, exploit a quantum information protocol in their new clock design. The technology could lead to improved timekeepers for satellite systems and for determining the values of fundamental scientific constants.