Synopsis

Engineering Molecular Transitions for Symmetry-Violation Tests

Physics 16, s154
Researchers have engineered ultracold molecular transitions ideally suited for probing beyond-standard-model effects of symmetry violations.
Y. Takahashi and N. Hutzler/Caltech

Ultracold atoms and molecules are promising platforms for sensitive tests of fundamental physics principles. For example, molecular spectra can be used to probe charge-parity (CP) symmetries, potentially revealing CP violations unforeseen by the standard model. So far, such CP-violation tests have delivered null results. That could change as tests become more sensitive. To that end, Yuiki Takahashi and his colleagues at the California Institute of Technology have now “engineered” molecular transitions insensitive to external magnetic and electric fields, which can produce noise large enough to hide CP-violation-induced signals [1]. Approaches using such molecular transitions could lead to order-of-magnitude sensitivity enhancements in CP-violation tests, Takahashi says.

For CP-violation tests, the molecules should be laser coolable down to microkelvin temperatures, the transitions should display sizeable energy shifts from CP-violation effects, and the transitions should be amenable to methods for rejecting systematic measurement errors. Scientists have identified molecules with these traits, but those molecules have pronounced sensitivities to external fields that can introduce energy shifts big enough to mask potential CP-violation signals.

Takahashi and his colleagues show that they can reduce this sensitivity 100-fold by polarizing the molecules with an electric field. As a result, the molecular transitions achieve “magic conditions” where the unwanted energy-level shifts produced by external fields will cancel out. The team characterized various diatomic and triatomic molecules, pinpointing promising targets for CP-violation tests. Takahashi says that he and his colleagues will soon run tests on a standout candidate, 173YbOH, a molecule that predictions indicate could manifest a measurable nuclear magnetic quadrupole moment if a CP-violation occurs within the Yb nucleus.

–Matteo Rini

Matteo Rini is the Editor of Physics Magazine.

References

  1. Y. Takahashi et al., “Engineering field-insensitive molecular clock transitions for symmetry violation searches,” Phys. Rev. Lett. 131, 183003 (2023).

Subject Areas

Atomic and Molecular Physics

Related Articles

A Pulsed Magnetometer Beats a Steady One
Magnetism

A Pulsed Magnetometer Beats a Steady One

An atomic magnetometer using a pulsed laser may offer higher sensitivity to signs of new physics than continuous-laser versions. Read More »

A Glimpse at the Quantum Behavior of a Uniform Gas
Atomic and Molecular Physics

A Glimpse at the Quantum Behavior of a Uniform Gas

An innovative way to image atoms in cold gases could provide deeper insights into the atoms’ quantum correlations. Read More »

Microwaves Can Suppress Chemical Reactions
Chemical Physics

Microwaves Can Suppress Chemical Reactions

The heating effect of microwaves has long been used to accelerate reactions. A new experiment shows that microwaves can also excite molecules into a less reactive state. Read More »

More Articles