Parity violation in chiral molecules

5 problems

• First measurement of the parity-violating energy difference between enantiomers

  Open

  The left- and right-handed forms of a chiral molecule should differ in energy by a tiny amount because of the weak force. No experiment has yet been sensitive enough to see it.

• Can parity violation bias the homochirality of biological molecules?

  Contested

  Life uses only left-handed amino acids and right-handed sugars, and the weak force slightly favors one handedness. The favoring is predicted to be extremely small, and it is unknown whether any natural chemical process could amplify it into a full preference.

• What stabilizes enantiomers: parity violation or environmental decoherence?

  Partially resolved

  Quantum mechanics without the weak force says a chiral molecule's true lowest state is an equal mix of left and right forms, yet real chiral molecules stay left or right for practical eternity. Whether the weak force or the molecule's surroundings fixes the handedness is still debated for molecules where the two effects are comparable.

• Nuclear anapole moments from molecular spectroscopy

  Open

  The weak force inside a nucleus produces a tiny magnetic feature called the anapole moment, measured so far only for cesium atoms. Polar molecules amplify this effect and could measure it for other nuclei, testing how the weak force acts between protons and neutrons.

• Accuracy of relativistic predictions of molecular parity-violating energies

  Open

  Calculations of the left-right energy difference must include relativity, electron correlation and molecular vibrations, and different methods can give answers differing by large factors. A trusted value with an error bar is needed before an experiment can test the weak force.