Foundations for Trapped Molecular Ion Parity-Violation Studies

Northwestern University, Evanston IL

Investigators

Abstract

This project develops techniques which enable measurement of mirror-symmetry violation, using molecular ions held for long periods of time, nearly at rest, and well isolated from their environment in linear radiofrequency traps. The major challenges to be overcome are development of capabilities to control and non-destructively read out the rotational quantum state of a single trapped molecular ion. Although molecules require extra care in control and readout as compared with atoms, the principle advantage is that opposite-parity rotational levels are intrinsically nearby in energy and thereby more substantially mixed by the weak force than are electronic levels of typical atoms. Nuclear spin-dependent parity violation is important for understanding purely hadronic weak interactions of the Standard Model, and they provide a special low-energy approach for searching for new physics at TeV energy scales. This work is motivated by nuclear spin-dependent parity-violation investigations, but other important applications of improved precision molecular spectroscopy include measurements of time-variation of the electron-proton mass ratio, study of parity violation in the structure of chiral molecules, and discovery of an electron electric dipole moment. Furthermore, the ingredients for single molecular ion spectroscopy, internal and external quantum state control and state readout developed here, could be essential elements for molecular-ion quantum information processing applications and for studies of low-temperature chemical reactions. The spectroscopic techniques being developed in this proposal have potential to impact other areas of science as diverse as atmospheric and astrophysical spectroscopy -- where there is great interest in developing improved methods and tools for molecular rotational and vibrational spectroscopy in the so-called molecular "fingerprint" region of the electromagnetic spectrum. A strong program of undergraduate and graduate education and training is maintained by the research. The current group of students in the lab is diverse and includes underrepresented minorities.