Many molecules, like gloves, come in left- and right-handed versions. Their energy difference, caused by the weak interaction, is minute, like a whisper in a noisy room. Physicists have figured out how to turn that whisper into a chorus. A mixture of precursor molecules in an ultracold gas yields mirror-image pairs. When cooled to a Bose-Einstein condensate, a state where atoms act as a single chorus, the slight surplus of one form gets amplified into total dominance.

Even accounting for thermal jitter and electric fields, nearly all molecules end up in one form, which can be detected by spectroscopic methods. This will not only confirm the theory but also bring us closer to understanding why in living systems, amino acids are left-handed and sugars are right-handed.