My group makes measurements on atoms and molecules to look for cracks in the structure of physical laws. Our projects involve

  • searching for the electron electric dipole moment
  • building new kinds of atomic clocks
  • testing quantum electrodynamics using hydrogen

SORCE: rubidium two-photon clock

Recent work

  1. Electron electric dipole moment searches using clock transitions in ultracold molecules, Phys. Rev. Lett. (2020)
  2. Nd+ isotope shift measurements in a cryogenically-cooled neutral plasma, Phys. Rev. A (2020)
  3. Improved estimate of the collisional frequency shift in Al+ clocks, Phys. Rev. Research (2019)
  4. A measurement of the atomic hydrogen Lamb shift and the proton charge radius, Science (2019)

    Perspective: Progress on the proton-radius puzzle

  5. Direct observation of a highly forbidden optical transition in Sm:SrF2, Phys. Rev. A (2019)
  6. Cold, dense, atomic ion clouds produced by cryogenic buffer-gas cooling, Phys. Rev. A (2019)
  7. Magic polarization for light shift cancellation in two-photon optical clocks, Phys. Rev. A (2019)

Selected older publications

  1. Collisional frequency shift of a trapped-ion optical clock, Phys. Rev. A (2017)
  2. Frequency-offset separated oscillatory fields, Phys. Rev. A (2015)
  3. Optical frequency standards for gravitational wave detection using satellite Doppler velocimetry, New. J. Phys. (2015)
  4. Order of magnitude smaller limit on the electric dipole moment of the electron, Science (2014)
  5. Search for the electric dipole moment of the electron with thorium monoxide, J. Phys. B (2010)


Code and hardware designs developed in my group are freely available at


Perhaps you are here for my list of content-free phrases?


I have taught the following courses:


MP 033 (lab), MP 1121 (office)
Department of Physics
University of Toronto
60 St. George Street
Toronto ON M5S 1A7, Canada

Phone: +1 416 946 8503
Email: amar.vutha Ͽ

'MP' is the McLennan Physics building, in the downtown campus. I am proud to work in a building named after an actual physicist.



  • Shira Jackson
  • Kristen Cote
  • Harish Ramachandran
  • Ryan Zazo
  • Sarina Xi
  • Camilo Sanchez
  • Takahiro Tow
  • Dr. Rhys Anderson
group photo


  • Dr. Kosuke Kato → National Research Council
  • Nishant Bhatt, PhD → PTB, Germany
  • Mohit Verma → U Chicago
  • Jinsoo Park → Queens U
  • Luca Talamo → U Colorado
  • Jack Davis → U Waterloo
  • Hiromitsu Sawaoka → Harvard
  • Wesley Cassidy → U British Columbia
  • Dr. Shreyas Potnis → Google
  • Dr. Graham Edge → JW Player
  • Jenny Wu → U Colorado