Simulating Particle Creation with Cold Atoms
In physics, you can get something from nothing. In a strong electric field, electrons and positrons are expected to pop into existence out of the vacuum. But exploring this so-called Schwinger effect in the lab is impossible because the required field strength (1016 V/cm) is far beyond reach. Now Zi-Hang Zhu from the University of Science and Technology of China and colleagues have simulated the effect of a strong electric field using cold atoms in an optical lattice. The atoms behave as particle physics would predict.
The Schwinger effect is an example of “false-vacuum decay” in quantum field theory. When a strong field prevails, the vacuum state without particles becomes unstable, and the system spontaneously transforms to a lower energy state with particles. These particles are pairs of electrons and positrons in the case of a strong electric field, but other particles and fields can exhibit false-vacuum decay, notably in the early Universe.
In their experiment, Zhu and colleagues placed ten rubidium atoms in a one-dimensional optical lattice. They tuned the potential energy of the lattice to control both the effective electric field and the effective mass of particles coupled to the field. The false-vacuum state was represented by a specific atomic arrangement with two atoms in every other lattice site. Using quantum gas microscopy, the team showed that one atom from a doubly occupied site eventually moves to a neighboring site. The resulting single-occupancy arrangement corresponds to pair creation.
Zhu and colleagues found that the pair-production rate depended on the effective mass and effective field, as expected for false-vacuum decay. In future work, the researchers plan to expand to higher dimensions and explore other quantum field predictions.
–Michael Schirber
Michael Schirber is the Deputy Editor of Physics Magazine.
References
- Z.-H. Zhu et al., “Probing false vacuum decay on a cold-atom gauge-theory quantum simulator,” Phys. Rev. Lett. 137, 141601 (2026).