ISI Directory

Justin M. Brown, PhD

Research Computer Scientist


Doctor of Philosophy in Physics, Princeton University (2011)
Master of Arts in Physics, Princeton University (2007)
Bachelor of Arts in Physics, Williams College (2005)


Dr. Justin M. Brown leads the Quantum Sensing Laboratory where he leverages two decades of atomic physics research experience in precision measurement and sensor design spanning academia and industry.  In 2005, Dr. Brown earned a BA from Williams College with Highest Honors in Physics where he was first introduced to the atomic physics laboratory by trapping cold rubidium atoms.  In 2011, he earned a PhD from Princeton under the direction of Michael Romalis where he performed precision tests of fundamental physics in warm vapor cells using a navigation-grade, nuclear-spin gyroscope incorporating techniques from atomic magnetometry at the femtotesla level.  Measurements included improving the limit on a cosmic Lorentz-violating background field to the neutron spin by a factor of 30 as well as a new limit on nonmagnetic spin-spin interactions between neutrons by a factor of 500.  Dr. Brown was awarded the Miller Postdoctoral Fellowship at Berkeley where he worked with Holger Müller to develop new instrumentation for matterwave interferometry to perform fundamental tests of gravity.  Experience measuring accelerations and rotations lured Dr. Brown to corporate environments to develop next-generation instrumentation for inertial navigation.  For nearly a decade, he contributed to and led government sponsored research contracts to develop specialized atom- and optical-based sensors for magnetic and inertial sensing applications before combining the applications knowledge with fundamental innovations in the ISI Quantum Sensing Laboratory.

Research Summary

Quantum sensors based on atoms offer the potential to build systems with the highest sensitivity and long-term stability. As demonstrated in atomic clocks, quantum measurements routinely provide the most accurate timekeeping both inside and outside the laboratory. The quantum advantage derives from the measurement of discrete atomic energy levels in a gas of atoms using light. This platform uniquely provides for consistent measurements since Nature has produced massive quantities of identical atoms where the interaction between light and atoms can be predicted to high precision through quantum mechanics. Furthermore, the electro-optic tools to prepare and manipulate light intensity, frequency, and polarization for controlled atomic interactions are well developed.

While advancements in atomic timekeeping are already mature, emerging applications in electromagnetic and inertial sensing are leading to further development of magnetometers, antennas, accelerometers, and gyroscopes. Despite a demonstrated quantum advantage in the laboratory, the full potential of quantum sensors for field applications has been limited by environmental requirements (temperature, orientation, and dynamic range) along with system size, weight, and power. The Quantum Sensing Laboratory aims to demonstrate new atom-based sensor architectures and supporting component technologies in order to facilitate their transition to applications outside the laboratory. These innovations leverage fundamental physics to either simplify device complexity or enhance capability, which will enable a more tractable starting point for engineering efforts and subsequent widespread deployment of quantum sensors outside the laboratory for inertial sensing and geophysical measurement applications.


Miller Postdoctoral Fellowship at UC Berkeley (2011-2013)