‘Quantum Paradox’ Experiment Could Enable More Accurate Sensors and Clocks

Facebook X LinkedIn Email
An international research team will test Einstein’s twin paradox using quantum particles in a superposition state — an experiment that could lead to more accurate sensors and clocks.

The twin paradox postulates that time can pass at different speeds for people who are at different distances from a large mass or who are traveling at different velocities. “For example, relative to a reference clock far from any massive object, a clock closer to a mass or moving at high speed will tick slower,” professor Magdalena Zych (University of Queensland) said. “This creates a ‘twin paradox,’ where one of a pair of twins departs on a fast-speed journey while the other stays behind.”

A clock moving in superposition of different speeds would measure a superposition of different elapsing times — in a quantum version of the famous 'twin paradox' of special relativity. Courtesy of Magdalena Zych.
A clock moving in superposition of different speeds would measure a superposition of different elapsing times in a quantum version of the famous ‘twin paradox’ of special relativity. Courtesy of Magdalena Zych.

When the twins reunite, the traveling twin would be much younger, as different amounts of time would have passed for each of them. Zych described this paradox as “one of the most counterintuitive predictions of relativity theory.”

The researchers will use advanced laser technology to realize a quantum version of the twin paradox. In the quantum version, instead of twins there will be one particle traveling in a quantum superposition. This means the particle will be in two locations at the same time. It will be in each location with some level of probability, but this is different from placing the particle in one or the other location randomly. “It’s another way for an object to exist, only allowed by the laws of quantum physics,” Zych said.

The team will show that closed light-pulse interferometers without clock transitions during the pulse sequence are not sensitive to gravitational time dilation in a linear potential and that they can constitute a quantum version of the special-relativistic twin paradox. The team has proposed experimental geometry for a quantum-clock interferometer that will isolate this effect.

“The idea is to put one particle in superposition on two trajectories with different speeds, and see if a different amount of time passes for each of them, as in the twin paradox,” Zych said. “If our understanding of quantum theory and relativity is right, when the superposed trajectories meet, the quantum traveler will be in superposition of being older and younger than itself. This would leave an unmistakable signature in the results of the experiment, and that’s what we hope will be found when the experiment is realized in the future.”

The experiment could lead to advanced technologies that will allow physicists to build more precise sensors and clocks for future navigation systems, autonomous vehicles, and earthquake early warning networks.

The team includes researchers from the University of Ulm and Leibniz University Hannover, as well as the University of Queensland.

The research was published in Science Advances (   

Published: October 2019
The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the atomic and subatomic scales. It originates from quantum theory, a branch of physics that emerged in the early 20th century to explain phenomena observed on very small scales, where classical physics fails to provide accurate explanations. In the context of quantum theory, several key concepts are associated with the term quantum: Quantum mechanics: This is the branch of...
quantum mechanics
The science of all complex elements of atomic and molecular spectra, and the interaction of radiation and matter.
Research & TechnologyeducationEuropeAsia-PacificUniversity of QueenslandquantumSensors & DetectorsLasersTest & Measurementquantum mechanicsEinstein’s twin paradox theoryTech Pulse

We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.