In quantum physics, there’s a state with even less energy than a vacuum, called a true vacuum, which is stable because it has the lowest possible energy. A metastable or “false” vacuum, however, is a hypothetical state that seems stable — but hasn’t actually reached its most stable state yet.
If our universe were in this false vacuum state, researchers fret that a strange chain reaction could trigger what’s called a “false vacuum decay” event, which could result in the abrupt and sudden end of the entire universe around us — a “doomsday”-level threat some physicists claim is entirely possible, albeit exceedingly unlikely.
Now, as detailed in a paper published in the journal Physical Review Letters, physicists in China claim to have simulated false vacuum decay using a lab-based “tabletop” experiment, laying the groundwork for future investigations into whether the universe could be wiped out in an instant.
Since the 1970s, scientists have suggested that a false vacuum could use quantum tunneling, a quirky facet of quantum physics, to fall into a “true” vacuum. Put simply, the idea is that particles can cross through energy barriers without actually possessing the required energy.
“While we cannot test this theory on a universal scale, the recent development of highly controllable quantum simulators allows us to recreate and study these dramatic tunneling events in tabletop experiments,” coauthor and Tsinghua University physicist Meng Khoon Tey told Phys.org.
The news comes after researchers used a powerful quantum computer to simulate a false vacuum decay event, as detailed in a 2025 paper.
For the latest experiment, the team of Chinese physicists set up a ring of Rydberg atoms, whose outermost electrons are at the highest energy levels they can maintain without leaving.
These atoms were arranged to be mutually repulsive to their respective neighbor, meaning that their spin states ran in opposite directions to each other.
The researchers then used a laser to deliberately break this ring, in an effort to simulate a false vacuum state.
“By illuminating alternating atoms with site-selective laser beams, we engineered a custom energy landscape with distinct ‘false’ and ‘true’ vacuum states, allowing us to watch the quantum tunneling process unfold in real-time,” Tey told Phys.org.
They found that the stronger the symmetry-breaking laser, the faster the simulated vacuum state decayed, supporting existing quantum field theory.
The researchers also observed that the system formed a “bubble” which contained a true vacuum state within it, thereby making it more likely to transition to such a lower energy state.
The experiment lays the groundwork for demonstrating the basic dynamics involved in a lab, per Tey, in a “stepping stone” for future explorations of the subject.
More on quantum physics: Scientists Say They’ve Found “Dark Points” That Move Faster Than the Speed of Light