Quantum Physics


National Security

Schwab Research Group 

Electro-mechanical structure which was cooled to the quantum ground state, prepared into a quantum squeezed state of motion, and demonstrated quantum non-demolition measurement techniques.

Caltech 2010.

Soaring in Bishop, CA with DG-505 (July 2015.)

Keith Schwab



Keith was born in 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 primarily 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 (superconducting qubits.) 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 microscocpy (Nature 2007).  Keith joined Caltech as an Associate Professor of Applied Physics in January 2009 and constructed 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 Schwab group has been active in the further development of techniques to cool motion to the quantum ground state (Nature 2010), demonstrate quantum non-demolition measurements of motion (Science 2014), creating and measuring quantum squeezing of mechanical motion (Science 2015),  and thermal transport in graphene at low temperatures.

Currently, the laboratory is focused on utilizing the unique quantum properties of superfluid helium-4.  We have coupled a gram-scale acoustic resonator of helium to a very low dissipation microwave cavity and have observed acoustic quality factors in excess of 100 million.  We expect this system to demonstrate the lowest acoustic loss of any material and to find application in the detection of narrow band gravitational wave from pulsars and the exploration of quantum physics at extremely small length scales.  Furthermore, we are exploring the transport of liquid helium through new 2D nanoporous materials (created by Prof. Ben King at Univ. of Nevada Reno) which is expected to demonstrate the Josephson effect far below the superfluid transistion temperature and be the basis of ultra-sensitive matter-wave interference gyroscopes.

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 (California, Alaska, Wyoming, New Mexico,) landscape photography, and piloting gliders (current personal records are: altitude: 18,000',  distance: 250mi, time: 4.2 hrs). Tracks of longer soaring flights.

For some examples of the photographs:


Nanostructure which demonstrated the quantum of thermal conductance.  This image is part of the permanent collection at the Museum of Modern Art, New York.