Exploring the Quantum Illusion of Time Through the World of Toys

The concept of time may be an illusion arising from quantum interactions within the universe. This theory is explored through experimental models. Researchers are gaining insights into the fundamental nature of time through these experiments.

Giovanni Barontini of the University of Birmingham began pondering the essence of time when observing his son play. “As he built his own microcosms, I realized it’s similar to our lab work with ultracold atomic systems,” he explained. “Yet, it struck me that this universe could feel quite dull, as nothing changes, leading one to wonder if time even exists there.”

To delve into whether time is truly an illusion in such models, Barontini utilized lasers and electromagnetic forces to cool approximately 20,000 rubidium atoms close to absolute zero. He categorized these atoms into two regions, likening them to dark matter, designating one as the “bright” and the other as “dark.”

Despite this unchanging, timeless model universe, Barontini manipulated the atoms with lasers, allowing them to exchange and interact at the quantum level. This process altered the entropy, reflecting how time flows in our universe, which inherently increases entropy. Consequently, he was able to characterize the internal time of this experimental setup. Furthermore, this new internal time was integrated into the Schrödinger equation, which governs the evolution of quantum systems, yielding results consistent with experimental data.

Historically, the perspective that time emerges from quantum correlations has roots in nuclear physics, first suggested by Neville Mott in the 1930s and explored theoretically ever since. In 2013, Marco Genovese and colleagues demonstrated this concept experimentally using entangled light particles, wherein the perception of time was derived from these quantum correlations.

“This study builds on that concept and introduces several significant advancements,” remarks Genovese. Notably, Barontini’s cold atom universe presents more complexity than earlier light-based models, successfully applying the Schrödinger equation to the internal time of the system—an unprecedented achievement.

Klaus Kiefer from the University of Cologne suggests that this experiment connects to broader questions about integrating gravitational and quantum theories into a unified framework. While this remains unresolved, some physicists propose that such a theory might fundamentally lack the concept of time. Although this experiment mirrors such a scenario, Kiefer notes that the ultracold atoms’ interactions differ significantly from those expected in the grand universe.

However, Carlo Rovelli from the University of Aix-Marseille indicates that this research may not unveil new knowledge about time, as it reflects well-established physics. Yet, treating these explorations as analogs for larger unresolved issues may inspire methods for approaching unknown realms of physics, akin to the complex challenge of quantum gravity.

For Barontini, this research lends experimental support to enduring theories, validating their relevance. However, he emphasizes that this does not confirm how time truly operates on any scale.

Cosmologists, dedicated to studying the universe at large instead of laboratory models, might challenge this research, Barontini notes. He remains keen to further investigate this icy mini-universe, potentially utilizing lasers to create regions that mimic the gravitational influence of black holes.