Keith was born St. Louis, Missouri in 1968. He attended St. Louis University High School and was active in electronics, early personal computers, amateur astronomy, and the Boy Scouts, earning the rank of Eagle Scout.
Keith began his physics education at the University of Chicago in 1986. He had the pleasure to work with Prof. Albert Libchaber and his research group during his undergraduate thesis project (Nature 1990).
He left Chicago with a BA in physics in 1990 and began his PhD studies at the University of California Berkeley where he studied ultra-low temperature physics with Prof. Dick Packard. His thesis project (PhD 1996) demonstrated a superfluid quantum interference device which was able to detect the Earth's rotation (Nature 1997).
In 1996, Keith joined Prof. Michael Roukes' research group at the California Institute of Technology as the Sherman Fairchild Distinguished Post Doctral Scholar. There he probed energy transport through mesoscopic mechanical structures and demonstrated the quantum of thermal conductance (Nature 2000).
In 2000, Keith left Caltech and joined the National Security Agency (NSA). He formed and led a research group focused primarly on the investigation of quantum effects in nano-electro-mechanical devices and the applications of nanotechnology to atomic and quantum optics experiments. These experiments have demonstrated the closest approach to the Heisenberg Uncertainty Principle for position measurements of any kind (Science 2004), measurements showing the closest approach to the quantum ground state for a mechanical oscillator (Nature 2006), and subtle quantum backaction effects which can be utilized to cool mechanical structures (Nature 2006.) During this time, Keith and his colleagues began to formulate schemes to produce mechanical superposition states using quantum electronic devices.
Beyond fundamental research, the period at the NSA allowed Keith to develop his interest in areas related to national security and the US Intelligence Community, especially during the post 9-11 period.
Keith joined the faculty of Cornell University Department of Physics in April of 2006. His research focused on techniques to cool mechanical structures to the quantum ground state (Nature 2010), and various aspects of nanotechnology such as radio-frequency scanning tunneling microsocpy (Nature 2007).
Keith joined Caltech as an Associate Professor of Applied Physics in January 2009 and is in the process of constructing an ultra-low temperature laboratory to probe the quantum limits of measurement. Together with Prof. Michael Roukes (Caltech), Dr. Pierre Echternach (JPL), and Prof. Matt LaHaye (Syracuse) they have produced the first measurements of a qubit coupled to a mechanical resonator (Nature 2009). This system is expected to be very rich and to lead to the formation of a quantum superposition of the mechanical device.
In recent years, the group has been active in the development of techniques to cool motion to the quantum ground state (Nature 2010), quantum non-demolition measurements of motion (Science 2014), thermal transport in graphene at low temperatures, and developing novel opto-mechanical systems based on the coupling between the motion of superfluid helium and superconducting microwave resonators.
Outside the laboratory, Keith is interested and participates in a broad range of activities where scientists can play an important role. Keith is a member of the Young Global Leaders which is a sub-group of the World Economic Forum and participates in the annual meeting at Davos Switzerland (2005, 2007, 2008). Keith has lectured at the Museum of Modern Art and participated in a Fred Friendly panel discussion for public television (PBS) on the issue of nanotechnology, privacy, and security. He is also active as a consultant for the US government and is deeply interested in issues of national security, foreign affairs, and the future of our nation. He is an active member of the Pacific Council on International Policy.
Keith enjoys hiking, backpacking and landscape photography.