Physicists at the University of Birmingham have created a “mini-universe” using 24,000 ultra-cold rubidium atoms to demonstrate that time can emerge from internal entropy rather than an external clock. By trapping these atoms in a Bose-Einstein condensate and splitting them into observed and unobserved sectors, lead researcher Giovanni Barontini provided controlled experimental evidence that time is defined by the exchange of entropy within a system.
How does a “mini-universe” define time?
Time does not need an external “ticking” mechanism to exist, according to research published in Physical Review Research by Giovanni Barontini. In his experiment, Barontini used a dipole optical trap to split a cloud of rubidium atoms, cooled to near absolute zero, into two distinct sectors. One sector remained observed while the other stayed dark, mirroring the relationship between observable matter and dark energy in our own cosmos.
As atoms moved between these sectors, the system exchanged entropy. Barontini explains that this movement acts as an internal, “entropic” clock. Because entropy naturally flows in one direction, the system creates an ordered sequence of events without needing an outside reference point. This finding challenges the traditional view of time as a fundamental, external parameter, suggesting instead that time is an emergent property of thermodynamic interaction.
The movement of atoms in Barontini’s experiment mimics the cycles of a “Big Bang” and “Big Crunch.” When atoms migrate into the bright, observed sector, it represents the expansion phase of a universe, while their return to the dark sector represents a contraction.
Why is this research important for quantum gravity?
Uniting general relativity with quantum mechanics remains the “impossible” dream of modern physics, and this experiment offers a new testing ground for those theories. By manipulating the trap shape, barrier height, and atom density, researchers can simulate extreme conditions like black holes or the early moments of the Big Bang, according to Barontini.
While Newtonian physics and the Wheeler-DeWitt equation often suggest that time might disappear at the deepest quantum levels, the second law of thermodynamics provides a clear “arrow” of time. Barontini’s work bridges this gap by showing that quantum systems can generate their own temporal direction through entropy. This provides a new framework for describing dynamics in quantum gravity experiments, potentially replacing or augmenting conventional models of time.
Future trends in quantum simulation
The ability to engineer mini-universes using cold-atom systems will likely lead to more precise simulations of cosmological phenomena. As physicists gain better control over atom interactions, they can move beyond simple models to test whether a gravitational collapse behaves like a singularity or bounces back into a new expansion phase.
This experimental approach contrasts with purely mathematical attempts to solve quantum gravity. While theorists often rely on complex equations to describe the nature of existence, Barontini’s laboratory-based method provides empirical data. Future studies may use these “quantum sticks” to prod the boundaries of space-time, offering insights into the nature of consciousness and the foundational properties of our universe that were previously inaccessible to direct observation.
Frequently Asked Questions
- Is time real or an illusion? According to Barontini’s experiment, time is an emergent property created by the flow of entropy within a system, rather than a fundamental, external ticking clock.
- What are Bose-Einstein condensates used for? These “slushy” states of matter, created at temperatures near absolute zero, serve as highly controllable platforms for simulating quantum mechanics and cosmological events.
- Can we simulate the Big Bang? Yes, by observing the rhythmic oscillation of atoms between sectors in a trapped system, researchers can simulate the expansion and contraction cycles analogous to the Big Bang and Big Crunch.
To stay updated on the latest breakthroughs in quantum mechanics, follow the Physical Review Research journal for peer-reviewed studies on emerging experimental physics.
What do you think about the nature of time? Does the idea of an “entropic clock” change how you view the universe? Share your thoughts in the comments below or subscribe to our newsletter for more updates on the frontiers of science.
