Nobel Laureate Visiting Vilnius University Talks about Time, Einstein, and the Coolest Things in the Universe
Coincidentally, upon awarding this year’s Nobel Prize in Physics, Vilnius University (VU) also hosted a physicist and Nobel Prize winner William Daniel Phillips. One of the world’s most famous physicists sure is an expert storyteller, often adding an element of showmanship, and spends a lot of time talking to young people, not only in the US but also all over the world, discussing the joys and importance of a career in science.
W. D. Philip was not a privileged child attending the best schools. He is the son of social workers from Pennsylvania and has achieved all his awards and prizes through hard work. The winner of the Nobel Prize in Physics says at the age of ten, he was certain he wanted to be a scientist.
“As I was growing up, it became increasingly clearer to me that being a scientist is the coolest thing you can imagine. One of my mottos is that a good day is a day when you learn something new. And when you’re a scientist, almost all good days are good as you’re always learning. And sometimes it’s something no one else knew. I also remember being in primary school and one of our teachers told us what it meant to pursue higher education - to get a bachelor’s degree, a master’s degree, a PhD. I remember it was explained to me that in a PhD, you write a dissertation and that dissertation has to reflect something that nobody else has ever done before. I couldn’t understand how that could be. How can you do something new that someone else hasn’t done before? And now we do that every day,” the scientist shares his memories.
What is time?
W. D. Phillips studies the phenomena caused by the interaction of atoms with light and the control of quantum information by single atomic qubits. The professor has developed methods for cooling and accumulating atoms with laser beams, and has developed a method for capturing atoms at low temperatures. In 1988, he cooled the atoms to a temperature six times lower than the theoretical limit that was previously set. In 1997, W. D. Phillips and his colleagues Claude Cohen-Tannoudji and Steven Chu were awarded the Nobel Prize for their developments of methods to cool and trap atoms with laser light.
The aforementioned advances later led to the creation of the first Bose-Einstein condensate, a new exotic state of matter, which had been predicted some 70 years earlier by Albert Einstein and the Indian physicist Satyendra Nath Bose. Very low temperatures help form a giant (collective) wave of atoms, called the Bose-Einstein condensate, where all the atoms are in the same quantum state. The atoms in this state are so chilled and slow that, in effect, they merge and behave as one single quantum entity that is much larger than any individual atom.
On an October evening, the Grand Auditorium of the VU Life Sciences Centre hosted a Distinguished Researcher at the US National Institute of Standards and Technology, a Distinguished Professor at the University of Maryland, who gave a famous lecture Time, Einstein and the Coolest Stuff in the Universe.
“Albert Einstein made all sorts of discoveries that changed the way we think about the nature of the universe, and continues to influence science and technology in the 21st century. He’s done so many things. But Einstein is probably most famous for his relativity theory. Relativity theory was so revolutionary that it changed the way we think about the very nature of space and time,” says the Nobel Prize winner.
What is time? What is this thing that moves from the future into the present and into the past but is always in the present? The answer, according to W. D. Philip, coined by Einstein, may seem a little superficial, since he said that “time is what a clock measures.”
“But by taking the idea that time is what a clock measures seriously, Einstein changed our ideas about what time is. But if time is what a clock measures, what is a clock then? Well, for me, a clock is something that ticks. Something that gives you a set of periodic events, allowing you to mark days, hours, or minutes. The oldest clock is the rotating Earth. When the Earth rotates, we see the sun rising and setting and mark the days,” explains the professor.
What gives a more accurate time?
The Nobel Prize winner said the Earth’s rotation is not consistent. This became very dramatically clear to him one day when he visited the US Naval Observatory.
“I was visiting a colleague who was going to show me the latest clocks they were making at the US Naval Observatory. And as we walked down the corridor, we passed a door that said: “Director of the Earth’s rotation.” Quite a responsible job, I’d say. But the point is that the Earth's rotation is not consistent, it varies,” the professor recalls cheerfully.
However, according to W. D. Philip, the thing that gives us the most accurate time is the thing that ticks most regularly, which is the ticking of atoms. Upon reaching an international agreement, the length of time will be measured in atomic seconds. Atomic clocks, the best timers ever made, are one of the wonders of modern science and technology. These ultra-precise clocks are indispensable in industry, commerce, and science. They are at the heart of satellite navigation systems that guide cars, planes, and travelers to their destinations.
While today’s best initial atomic clocks using ultracold atoms will neither gain nor lose a second in 300 million years, the next-generation atomic clocks are forcing us to redefine what time means. Extremely cold atoms, which can be less than a billionth of a degree above absolute zero, allow for testing some of Einstein’s wildest predictions and theories.