Ultracold Condensate Turns Weak Molecular Asymmetry into Complete Handedness express
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.
Original abstract
as written by the authors arXiv:2606.08717
We propose a theoretical mechanism to indirectly detect the small parity-violating energy difference (PVED) between chiral enantiomers through a macroscopic enantiomeric excess observed in an ultracold gas. We consider that chiral molecules are formed resonantly via ultracold collisions of achiral diatomic molecules, with PVED inducing a slight asymmetry in the resonance energies of right- and left-handed configurations. After formation, chiral molecules evolve within a Bose-Einstein condensate (BEC), incorporating nonlinear interactions, tunneling between enantiomeric states, intrinsic PVED, and thermal conversion rates. These collective dynamics enable amplification of the microscopic bias into a global population imbalance. Using coupled rate equations, we show that, under realistic regimes, a complete enantiomeric excess can be achieved even for extremely small intrinsic asymmetries. We illustrate the model with concrete examples (HSOH, H$$_2$$Se$$_2$$, H$$_2$$Te$$_2$$), predicting observable enantiomeric excesses under plausible experimental conditions. We also consider non-PVED effects that could be amplified under the proposed mechanism, including electric and magnetic fields as well as thermal fluctuations, the latter being illustrated through the aforementioned molecular examples. Overall, our results suggest that ultracold physics could provide a new pathway to probe molecular parity violation, a fundamental weak effect that remains experimentally undetected.
Bose condensate temperatures can be less than a billionth of a degree above absolute zero, the coldest known state of matter.
The idea of mirror molecules recalls Alice’s journey through the looking-glass, where the world appears as its exact but opposite copy.