Super-accurate clocks emerge from 'heat haze'

Clocks that gain or lose no more than a fraction of a second over the lifetime of the universe could be on the way, thanks to a technique for cutting through the "heat haze" that compromises the accuracy of today's instruments.

The most accurate atomic clock we have now is regulated by the electrons of a single aluminium ion as they move between two different orbits with sharply defined energy levels. When an electron goes from the higher energy level to the lower it emits radiation of a precise frequency. That frequency is used to mark out time to an accuracy of better than 1 part in 10¹⁷, or 1 second in 3 billion years.

That's pretty good, but it could be better. Infrared photons emanating from the background cause the two energy levels to shift by slightly different amounts, says Marianna Safronova at the University of Delaware. That affects the frequency of the emitted radiation to an unknown extent, adding a small uncertainty to the clock's tick.

Safronova reported this month at a conference in Baltimore, Maryland, that by combining two different mathematical approaches, she and her colleagues have now managed to calculate how much the energy gap between the two levels changes.

Using this information to correct an atomic clock could in principle increase its precision to around 4 parts in 10¹⁹, or about 1 second per 80 billion years. Such a clock could test whether the fundamental constants of nature are changing, Safronova suggests.

Microsoft Vs Google

In San Francisco this week, two remarkable events took place just blocks away from each other: Google announced its ambitions to dominate the world of entertainment, through music and movie services, and even unveiled wireless-controlled lightbulbs.

On the same day, Microsoft’s chief executive Steve Ballmer took to the stage to reveal that the Windows-manufacturer had spent $8.5 billion on phone and web communications tool Skype. The next day, Google announced that it was launching an operating system and computers of its own, called Chromebooks, that will compete directly with Windows.

The battle between two tech giants, and implicitly Apple as well, encapsulates a trend – as technology becomes more capable, the lines between business and personal use are blurring rapidly. Consumers believe, increasingly, that putting up with outdated systems at work is unnecessary and counterproductive.

Kurt DelBene, president of Microsoft’s Office division, says this trend is encapsulated by the Skype deal. “There are natural interconnection points, whether it’s Xbox users who can reach out to all Skype users, or Office users.”

Created as a new, independent division reporting directly to Ballmer, Skype was attractive to Microsoft “because the vision that it has as a company is an exciting one for us,” says DelBene. “What it was trying to do in the consumer space is very similar to what we were trying to do in the business space. The reason people gravitated to them was because they were so good.”