All posts tagged: atomic clocks

Physicists use thorium-229 to power the world’s first working nuclear clock

Physicists use thorium-229 to power the world’s first working nuclear clock

Published by Jenni Sidey

A clock built from thorium-229 has crossed an important line, from a long-discussed concept to a working device. The shift matters because this clock does more than keep time. It can also watch for tiny changes in the forces that shape the universe. The new system uses a nuclear transition in thorium-229 rather than the electron-shell transitions used in conventional atomic clocks. That distinction has made the isotope one of physics’ most closely watched candidates for next-generation timekeeping. The transition sits at 148 nanometers, making it accessible to lasers, and its unusual origin gives it an added role as a probe of fundamental physics. For years, thorium-229 was valued for its potential. Now the device has been demonstrated as a stand-alone nuclear clock, with a continuous-wave laser stabilized directly to the isotope’s nuclear transition inside a calcium fluoride crystal at room temperature. A fluorite crystal containing atoms of the radioactive element thorium-229. It was used to precisely measure the absorption spectrum of atomic nuclei at the National Metrology Institute of Germany (PTB). (CREDIT: Weizmann Wonder …

Atomic clocks may be powerful enough to detect the quantum fabric of time

Atomic clocks may be powerful enough to detect the quantum fabric of time

Published by Jenni Sidey

Time feels familiar. It marks every moment of daily life, from the ticking of a wall clock to the changing numbers on a smartphone screen. Yet despite its constant presence, time remains one of the deepest mysteries in science. For more than a century, physicists have known that time is not fixed. Albert Einstein’s theory of relativity showed that time can speed up or slow down depending on motion and gravity. The faster an object moves, or the closer it is to a massive object, the more differently it experiences time. But another revolution in physics, quantum mechanics, introduced an even stranger possibility. At the quantum level, particles can exist in multiple states at once through a phenomenon called superposition. If motion can exist in a superposition, then time itself may also flow in multiple ways simultaneously. Scientists have long wondered whether this bizarre idea is real. Until now, no experiment has been capable of testing it. Illustration of classical, semiclassical, and quantum proper time dynamics of a trapped-ion atomic clock that we consider. (CREDIT: …

Breakthrough ion clock experiments reveal that time can go quantum

Breakthrough ion clock experiments reveal that time can go quantum

Published by Jenni Sidey

Time already behaves strangely in modern physics. It can stretch, slow, and split depending on speed and gravity. Now a new theoretical study pushes that weirdness into even stranger territory. It argues that time itself may carry quantum signatures that could soon be tested with some of the most precise clocks ever built. That idea sounds almost like science fiction. In everyday life, a clock ticks one second at a time, in one direction, at one rate. In relativity, that neat picture breaks down because motion changes how quickly time passes. A moving clock runs differently from one at rest, even if the difference is tiny. But quantum physics adds another twist, because motion itself can exist in superposition. With this, a particle can effectively occupy more than one state at once. Put those two ideas together and the result is startling. A clock whose motion follows quantum rules may not experience one clean flow of time. In principle, it could evolve along different time paths at once, ticking both faster and slower in a …