Counting the Seconds That Could Change Physics

UC Berkeley physicist Shimon Kolkowitz explains atomic clocks in just 101 seconds.

Most of the atomic clocks in the world — fewer than 500 in total — are housed at standards institutes and used to keep time for the planet. But the one inside UC Berkeley’s Kolkowitz Lab has a different mission.

Instead of just measuring time as a resource for the rest of the world, this is an experiment to “test fundamental physics, to search for new physics, and to test relativity,” explains Professor Shimon Kolkowitz in this 101 in 101 video, a series from UC Berkeley that challenges experts to distill their area of study into a mere 101 seconds.

Quantum physics was a struggle for Kolkowitz when he first studied it in his university days. Yet the challenges it presented intrigued him and drew him into a discipline that is now celebrating its 100th year. Today, Kolkowitz is Herst Chair in Physics and runs a lab where he and a number of students search for new laws of physics by measuring the oscillations of very, very cold atoms of strontium using their optical lattice atomic clock.

How cold? Well, inside the vacuum chamber, they are the coldest place in the known universe – apart from the dozens of other similar experiments on the planet (a millionth of a degree above absolute zero, to be precise). The cold, the lasers and the lattice enables the team to manipulate and trap atoms, to move them around, and to form multiple clocks using some of the most precise measurements ever made.

We may not realize it, but we all benefit from atomic clocks on a daily basis. “The GPS network is just a bunch of satellites with very precise atomic clocks in them,” explains Kolkowitz, “and your phone collects the signals from all of those clocks and triangulates them to figure out exactly where you are on the surface of the Earth.” 

Furthermore — and beauty influencers, take note — thanks to quantum physics, gravity and atomic clocks, we now know that your head is actually aging slightly faster than your feet. “These clocks are so precise that they can detect the subtle changes in the passage of time due to relativity,” Kolkowitz explains. 

In all seriousness, this precision is critical for science, commerce and defense, and though the measurements are mind-bogglingly exact, Kolkowitz and his colleagues and students are in search of even more precision in their measurements.

Although atomic clocks have been around since the late 1950s, when they were first demonstrated, they are at the forefront of new physics research today. Kolkowitz humbly acknowledges that he stands on the shoulders of giants who’ve gone before him, many of them at UC Berkeley. “This very complicated experiment is the culmination of a century or more of work into understanding atoms and how to manipulate them,” he says. Just a few weeks ago, UC Berkeley professor emeritus John Clarke won the Nobel Prize in physics for his work on quantum tunneling, which he conducted at Berkeley with Michel Devoret and John Martinis in the early 1980s.

“It was so exciting for John Clarke to win the Nobel Prize; the research he did was so foundational for quantum science,” says Kolkowitz. “I don’t believe that their primary intention was to one day be able to build a quantum computer. And similarly with clocks like this, we’re doing basic research with the hope that people will build on the work that we do and develop entirely new technologies, and also to give us more insights into the universe around us.”

Watch more 101 in 101 videos featuring UC Berkeley faculty and experts here.