Physicists have proposed a striking new idea about the nature of time. Their work suggests time itself may carry a tiny fundamental uncertainty. Consequently, this could place an ultimate limit on clock precision. However, the effect remains far too small to ever detect.
The international team explored alternatives to standard quantum mechanics. Specifically, they examined theories called quantum collapse models. These findings appeared in the journal Physical Review Research. The Foundational Questions Institute supported the research directly.
The team included Catalina Curceanu, a member of FQxI and research director at the Laboratori Nazionali di Frascati of the National Institute for Nuclear Physics (INFN-LNF) in Frascati, Italy, Kristian Piscicchia, at CREF and INFN-LNF, Lajos Diósi, of the Wigner Research Center for Physics and Eötvös Loránd University, in Budapest, Hungary, and Simone Manti of INFN-LNF.
Understanding the idea requires some quantum background first. In quantum theory, particles can exist in multiple states simultaneously. Physicists describe these possibilities using a mathematical wavefunction. Standard theory says observation collapses this into one definite outcome.
“What we did was to take seriously the idea that collapse models may be linked to gravity,” says Nicola Bortolotti, a PhD student at the Enrico Fermi Museum and Research Centre (CREF) in Rome, Italy, who led the study. “And then we asked a very concrete question: What does this imply for time itself?”
However, collapse models take a more radical approach entirely. The researchers propose that collapse can happen spontaneously without observation. Crucially, these models predict measurable physical effects. This distinguishes them from purely conceptual interpretations of quantum mechanics.
The team studied two specific collapse models closely. One was the well-known Diósi-Penrose model. It proposes that gravity forces quantum systems into definite states. They also examined Continuous Spontaneous Localization for the first time.
Both models describe a continuous, spontaneous measurement of matter. Specifically, this targets the mass density field of quantized matter. The researchers linked this mechanism to Newtonian gravity uncertainties. Notably, they connected both models, not just Diósi-Penrose.
The physics behind the conclusion is subtle yet elegant. These collapse effects induce fluctuations in the Newtonian potential. Consequently, that uncertainty ripples directly into the flow of time. As lead author Nicola Bortolotti explains, a spacetime wobble means a ticking wobble.
Bortolotti and colleagues then calculated the size of that wobble. Their answer sits far below anything modern instruments register. Even the best atomic clocks fall nowhere near it. He called the result “clear and surprisingly reassuring” overall.
Co-author Catalina Curceanu stressed the practical takeaway firmly. The uncertainty is many orders of magnitude below measurement. Therefore, it carries no consequences for everyday timekeeping whatsoever. Modern timekeeping technologies remain entirely unaffected by the finding.
“There are not many foundations in the world which are supporting research on these types of fundamental questions about the universe, space, time, and matter,” says Curceanu. “Our work shows that even radical ideas about quantum mechanics can be tested against precise physical measurements, and that, reassuringly, timekeeping remains one of the most stable pillars of modern physics.”
The work touches one of physics’ biggest unsolved problems. Namely, how to reconcile quantum mechanics with gravity. These two pillars treat the concept of time differently. Quantum theory treats time as an external, fixed parameter.
General relativity, however, treats time as flexible spacetime. This structure bends in response to mass and energy. This fundamental mismatch has puzzled physicists for many decades. The new results may offer subtle clues toward unification.
Since collapse models predict measurable, distinct effects, precise experiments could test them. This offers a fresh way to distinguish rival theories. Reassuringly, the researchers confirmed timekeeping remains a dependable pillar, so don’t chuck out those clocks yet.
