For the very first time Quantum wave in helium dimer filmed

For the very first time Quantum wave in helium dimer filmed

Anyone entering the world of quantum physics must prepare themself for quite a few things unknown in the everyday world: Noble gases form compounds, atoms behave like particles and waves at the same time and events that in the macroscopic world exclude each other occur simultaneously.

Helium is called a noble gase precisely because it does not form any compounds. However, if the gas is cooled down to just 10 degrees above absolute zero (minus 273 °C) and then pumped through a small nozzle into a vacuum chamber, which makes it even colder, then—very rarely—such helium dimers form. These are unrivaledly the weakest bound stable molecules in the Universe, and the two atoms in the molecule are correspondingly extremely far apart from each other.

Helium dimers measure 52 angstrom.

The scientists in Frankfurt irradiated such helium dimers with an extremely powerful laser flash, which slightly twisted the bond between the two helium atoms. This was enough to make the two atoms fly apart. They then saw—for the very first time—the helium atom flying away as a wave and record it on film.

That the researchers were able to observe and film the helium atom flying away as a wave at all in their laser experiment was due to the fact that the helium atom only flew away with a certain probability: With 98% probability it was still bound to its second helium partner, with 2% probability it flew away. These two helium atom waves—Here it comes, quantum physics!—superimpose, and their interference could be measured.

The laser pulse irradiation method we’ve now developed might allow us in future to observe the formation and decay of Efimov systems and thus better understand quantum physical systems that are difficult to access experimentally. »

Professor Reinhard Dörner (left) and Dr Maksim Kunitzki in front of the COLTRIMS reaction microscope at Goethe University, which was used to observe the quantum wave. Credit: Goethe University Frankfurt

Source : https://phys.org/