An international team of researchers has demonstrated a theoretical framework showing that state-of-the-art trapped-ion atomic clocks could be tuned to a sensitivity precise enough to measure the quantum superposition of time, in which different flows of time exist simultaneously at the quantum level.
The researchers behind the framework said the next step will be to prove their concept experimentally. If successful, they suggest that trapped-ion atomic clocks could potentially help unravel physics’ other fundamental question: the elusive nature of gravity.
Quantum Superposition, Gravity, Atomic Clocks, Albert Einstein, and the Flow of Time
In the macro world, time moves in one direction. Although famed 20th-century scientist Albert Einstein showed that gravity and speed can alter the rate at which time flows, his theory of relativity conceded that time at the macro scale inexorably flows in a forward direction.
As recently reported by The Debrief, the research team behind the new theoretical framework notes that this arrow of time remains poorly understood, leading to several theories attempting to explain how it actually works. For scientists studying behavior at the quantum scale, the movement of time becomes even more complex. That’s because time can exist in superposition, a state where different flows of time all exist at the same moment. However, the team notes, this “interplay of time” between relativity and quantum physics has not yet been experimentally verified.
Curious if new, state-of-the-art trapped-ion atomic clocks were precise enough to measure the quantum superposition of time to quantify different flows of time occurring at the same moment, researchers from Kyushu University, in collaboration with the Stevens Institute of Technology, University of Waterloo, the National Institute of Standards and Technology, Colorado State University, and Stockholm University, explored a theoretical framework capable pf capturing this elusive phenomenon.
Theoretical Framework Improves Sensitivity ‘By 100 to 1000 Times’
According to a statement announcing a potential breakthrough in measuring the quantum superposition of time, atomic clocks work by monitoring the frequency of certain atoms. This fundamental design enabled unprecedented timekeeping accuracy, with applications in satellite navigation and GPS systems.
The team notes that state-of-the-art trapped-ion configurations of atomic clocks are so precise and sensitive that “they can detect the time dilation predicted by Einstein’s theory over a height difference of a few millimeters.”
Associate Professor Joshua Foo of Kyushu University’s Institute for Advanced Studies, and one of the lead authors of the paper detailing the measurement framework, said it is the precision of these cutting-edge instruments that motivated his team to design their theoretical model.
“We found that the atomic clock’s motion becomes ‘entangled’ with its internal energy,” Professor Foo explained. “The signature of this entanglement is that the clock itself loses some of its quantum properties, which can be detected using modern techniques.”
When Foo and colleagues introduced a new technique for controlling the motion of these advanced atomic clocks, the professor said their framework indicates an improvement in sensitivity to this effect “by 100 to 1000 times.”
Experimental Proof and Probing the Nature of Gravity
When discussing the possible impact of their new theoretical framework, should it ultimately be used to quantify the quantum superposition of time, the researchers noted that it established atomic clocks as a viable tool for exploring several phenomena in the quantum world that had previously proven difficult to measure accurately, including the quantum nature of time. They also note that it “opens a new experimental frontier in fundamental physics,” as well as offering a viable path to more precise, next-generation atomic clocks.
Next, Foo said that the team is developing a detailed real-world experiment “bringing our theoretical model to reality.” If successful, these upcoming efforts will provide further insights into their model that do not appear in the theoretical version. The research also said his team is interested in whether atomic clocks based on their model could be used to probe the quantum realm of gravity, which he calls “the other fundamental question in physics.”
The study “Quantum Signatures of Proper Time in Optical Ion Clocks” was published in Physical Review Letters.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.