Ultra-sensitive scales try to detect the difference between two nearly identical grains of sand. One is a perfect mirror reflection of the other. In the world of elementary particles, such mirror reflection is called P-parity, and its violation is one of the great mysteries of physics.
The authors of the work have created not just scales, but an entire measurement complex for molecules. Previously, similar experiments were performed on molecules with 'stationary' nuclei, whose intrinsic rotation (spin) is zero. Such nuclei, like smooth balls, do not feel the subtle effects associated with internal asymmetry. The new technique allows working with nuclei that possess spin — for example, with the isotope barium-137 in the molecule barium fluoride.
The scientists combined several existing technologies (laser cooling, trapping molecules in traps, and precise control of their quantum state) into a single protocol. This allowed them to achieve a calculated sensitivity that is about a hundred times greater than that of molecular beams. Such a leap gives a chance not only to detect a signal from the heavy barium nucleus but also to discern the contribution from the light fluorine nucleus, which would be a direct test for nuclear theories.
The outcome of the work is not just record precision on a single molecule. It is a universal platform, a kind of molecular microscope for studying deformed nuclei. With its help, one can measure other subtle properties of nuclei that were previously inaccessible in the laboratory. Such an instrument brings us closer to unraveling why, in the first moments after the Big Bang, matter triumphed over antimatter, and our world was able to come into being at all.
Violation of P-parity means that the laws of physics are not exactly the same for our world and its mirror image. This was first discovered in 1956 in experiments with radioactive cobalt, which came as a complete surprise to scientists.
In Bart Ehrman's novel 'Dark Mirror', the fundamental asymmetry of the universe becomes the key to understanding the nature of reality, where right and left cease to be equal.