Physicists led by professor at the Barcelona Institute of Science and Technology Maciej Loewenstein found that as a result of the collision of atoms with high-energy photons, a series of quantum interactions can occur that transform light particles into a state similar to Schrödinger’s cat.

Schrödinger’s cat is a thought experiment that was proposed by one of the founders of quantum mechanics Erwin Schrödinger in 1935 during a discussion of the physical meaning of the wave function: his idea was to put a cat in a closed box and a mechanism that opens a container with poison in the event of a decay of a radioactive atom.

This event can happen at any arbitrary time and the animal will die, but this cannot be recognized until you open the lid.

In recent years, physicists have experimented with creating Schrödinger’s cats that can be seen with the naked eye. The authors of the new work were able to create its optical analogue.

The researchers became interested in how the quantum nature of light particles affects the change in their properties when colliding with electrons orbiting the nucleus of an atom. Traditionally, these interactions are calculated using the laws of classical physics, since they involve millions of photons and a large number of atoms and electrons.

During the experiments, the authors selected such a technique for observing the collisions of atoms and particles of light, which allowed them to track how the behavior and properties of individual photons change under the influence of quantum processes. It turned out that earlier their role in the interactions of powerful laser beams and matter was now greatly underestimated.

As a result, it turned out that the interactions between the laser beam and the electrons inside the atom made single photons go into a special quantum state in which they simultaneously possessed two different sets of properties: it looked like Schrödinger’s cat.

The interactions between super-powerful flashes of light and matter are traditionally described using the language of classical physics, without considering their quantum nature. Our experiments have shown that the interaction of powerful laser pulses and atoms leads to the fact that light particles pass into a quantum state, similar to the “Schrödinger’s cat.”

Research text