The next atomic clocks could keep accurate time for the entire life of the universe

Illustration for article titled The next atomic clocks could keep accurate time for the entire life of the universe

The atomic clocks we've already got are marvels of precision timekeeping, but their successors could be something else altogether, losing less than a second every 80 billion years. That could allow us to probe some of physics's most fundamental questions.

Anyone who has ever had to wind a watch knows that, over time, clocks will stop keeping entirely accurate time. The most precise atomic clocks currently in operation rely on the movement of electrons between energy orbits in a single aluminum ion. Because the electrons in such an ion will move from the higher energy orbit to the lower orbit at an extremely precise frequency, we can use that movement to keep time, allowing for clocks that will remain accurate for roughly 3 billion years before they lose even a second.

Now, that's pretty good, certainly for anyone who wants to use those clocks to simply keep time. But the problem is that, over time, background photons will cause the energy levels in the aluminum ions to shift around a bit, which makes the frequency shift around a bit. Since physicists can't adjust for that variance, they can't maintain the accuracy of the clock, which is why a second is lost every three billion years. Building even more accurate atomic clocks will require finding a way around that issue.


That's where the University of Delaware's Marianna Safronova enters the picture. She and her team have found a way through the so-called "heat haze" created by these photons, and they can combine a pair of mathematical approaches to figure out how the energy gap will vary over time.

If this new approach holds up, it would allow us to build atomic clocks that would only lose a second every 80 billion years or so, and possibly even better than that. We're getting close to the point that we would be able to build clocks that would keep accurate time for as long as the universe is around (or at the very least, until the universe expands into nothingness).

Even more excitingly, such clocks could monitor incredibly subtle changes over far shorter time periods. The most intriguing possibility is that we might be able to test whether the fundamental constants of the universe are really constant, or if they are in fact changing. Any changes would be exceptionally minute, beyond even the level of precision that our current atomic clocks could muster - but this new generation might be able to do it.

Via New Scientist.


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Out of curiosity: How do you read the time on such a clock without without altering its state and making it inaccurate? Do I even want to know?