Lan Cheng
Johns Hopkins University, MD·Chemistry
Why does the universe contain far more matter than antimatter? The Standard Model of particle physics explains a great deal but cannot answer this question.
- Fields
Chemistry
Physics
- Topics
quantum chemistry
computational chemistry
precision measurement
- Grants
- 1 known grant, through Jul 2029
What they work on
- Develop relativistic quantum-chemical methods that accurately describe how electron and nuclear motions couple in heavy-atom molecules, a key input for designing laser-cooling and precision-measurement experiments.
- Predict molecular sensitivity parameters, which set how strongly a system responds to time-reversal-symmetry-violating interactions, using relativistic all-electron first-principles calculations.
- Apply the new methods to radioactive molecules containing radium and to emerging solid-state platforms to identify the most promising candidates for searches beyond the Standard Model.
- Work with experimental laser-cooling and precision spectroscopy groups so the theoretical predictions guide and help interpret their measurements.
More about the research
Physicists suspect hidden forces that break basic symmetries of nature. One sensitive way to look for them uses tabletop experiments on molecules. Molecules containing heavy atoms can greatly magnify tiny symmetry-breaking effects. Choosing the best molecules and interpreting the measurements both require very accurate theory.
Why it matters
Explaining why matter dominates antimatter is one of physics' deepest open problems. Accurate predictions could help experimental groups choose the molecules and materials most likely to reveal new physics, saving costly trial and error. The computational tools for heavy-element molecules and materials may also serve researchers in chemistry, physics, and materials science.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Christopher Crawford
University of Kentucky, KY·Physics
Search for time-reversal symmetry violation by sending polarized neutrons through polarized nuclei, using low-energy neutron–nucleus resonances to amplify the effect, within the NOPTREX collaboration.
Benjamin Augenbraun
Williams College, MA·Physics
Measure the electronic, vibrational, rotational, and hyperfine (nuclear spin) structure of molecules pairing copper, silver, or gold with lead, using laser spectroscopy to see which wavelengths of light they absorb.
Andrea Shindler
University of California-Berkeley, CA·Physics
Calculate the electric dipole moments of protons and neutrons induced by theories beyond the Standard Model, to probe the source of the universe's matter-antimatter asymmetry.
The school
Johns Hopkins University: 100 labs on PI Pages, $4.1B a year on research, 622 research doctorates a year.
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