A recent example was published in 2025 by researchers, among others, from the European Electron X-ray Laser Laboratory near Hamburg. They cooled iodopyridine, an 11-atom organic molecule, to almost absolute zero and hit it with a laser pulse to break the atomic bonds. The team found that the motions of the released atoms were interconnected, indicating that despite its cooled state, the iodopyridine molecule was vibrating. “Initially, that wasn’t the main goal of the experiment,” he said Rebecca Bollexperimental physicist at the facility. “It’s basically something we found.”
Perhaps the most renowned zero-point energy effect in a field was predicted by Hendrick Casimir in 1948, spotted in 1958, and finally observed in 1997. Two plates of electrically uncharged material – which Casimir imagined as parallel sheets of metal, although other shapes and substances will do this too – exert a force on each other. Casimir said the plates would act as a kind of guillotine for the electromagnetic field, cutting off long-wave oscillations in a way that would disrupt the zero-point energy. According to the most accepted explanation, in some sense the energy outside the plates is higher than the energy between the plates, and this difference attracts the plates together.
Quantum field theorists typically describe fields as a collection of oscillators, each with its own zero-point energy. There are an infinite number of oscillators in the field, so the field should contain an infinite amount of zero-point energy. When physicists realized this in the 1930s and 1940s, they initially doubted the theory, but soon came to terms with infinity. In physics – or at least in most physics – differences in energy are what really matter, and with caution, physicists can subtract one infinity from the other to see what is left.
However, this does not work with gravity. Already in 1946, Wolfgang Pauli realized that an infinite or at least gigantic amount of zero-point energy should create a gravitational field forceful enough to explode the universe. “All forms of energy gravitate,” he said Sean Carrollphysicist from Johns Hopkins University. “This includes vacuum energy, so it can’t be ignored.” Why this energy remains gravitationally muted still baffles physicists.
In quantum physics, the zero-point energy of the vacuum is more than a constant challenge and more than a reason why you can never truly empty the box. Instead of being something where there should be nothing, it is nothing that has the potential to be anything.
“The interesting thing about a vacuum is that every field, and therefore every particle, is represented in some way,” Milonni said. Even if there is not a single electron in it, the vacuum contains “electronity”. Vacuum zero point energy is the combined effect of all possible forms of matter, including those we have not yet discovered.
Original story reprinted with permission Quanta Magazineeditorially independent publication Simons Foundation whose mission is to enhance society’s understanding of science by incorporating research developments and trends in mathematics and the physical and life sciences.