David E. Pritchard

Born in New York City in 1941, David E. Pritchard graduated from Caltech (B.Sc.  1962) and Harvard (Ph.D. 1968).  Employed since then in the physics department at MIT where he is currently Cecil and Ida Green professor and Associate Director of the Research Laboratory of Electronics, he has pursued research in atomic, optical, and molecular physics and physics education.  He was awarded the IUPAP Senior Scientist Medal in Fundamental Metrology 2008, 2004 Max Born Award by the Optical Society of America, the 2003 Schawlow Prize in Laser Science, and the 1991 Broida Prize of the American Physical Society, the latter with the citation “For outstanding contributions to atomic, molecular and optical physics including his monumental studies of energy transfer in molecular collisions; seminal research on atom wave interferometry and atom optics; numerous studies of the forces of light on atoms and their applications to atom cooling and trapping; and his development of single ion mass spectroscopy.”

Pritchard has a life-long interest in teaching problem solving in physics.  In the 1970’s he authored a Mechanics Workbook, a programmed instruction manual for Newtonian mechanics.  He also has a large collections of puzzles and paradoxes in physics and has taught a 10-hour course in this many times during MIT’s January Independent Activities Period.  He also collects “physics for lunch” problems, each one of which typically puzzles beginning graduate students for a lunch period.  His interest in teaching people to solve problems led to the collaboration with his son, Alex on CyberTutor, an interactive web-based program which is dramatically superior to written homework in raising students’ test scores.  It was refined and marketed as Mastering Physics.com, MasteringChemistry and …Astronomy) by their company Effective Educational Technologies which is now owned by Pearson Education.  This past year ~200,000 students used this learning tool in physics and another ~1,000,000 in Astronomy, Chemistry, and Biology.  His research in education – especially the Modelling Applied to Problem Solving pedagogy and the Integrated Learning Environment for Mechanics – underlie his current free online physics course.  He is the undergraduate major coordinator for physics undergraduates, and has won the MIT Dean’s award for teaching and advising and the Earll M. Murman Award for Excellence in Undergraduate Advising (2010).

Pritchard is a member of the National Academy of Sciences, and a Fellow of the American Academy of Arts and Sciences, the American Association for the Advancement of Science, the American Physical Society, and the Optical Society of America.  He was a member of the board of directors of the Optical Society of America (1996-2000), and has been selected as Centannial Lecturer by the APS and as Distinguished Traveling Lecturer by its Laser Science Topical group, and twice as Distinguished Visitor at the Joint Institute for Laboratory Astrophysics at the University of Colorado, and as the Johnson Lecturer at West Point.  He has spent sabbaticals at SRI International and the Universite de Paris Sud at Orsay.  He has published over two hundred papers in refereed scientific journals, received hundreds of invitations to speak at national or international meetings, and has two patents.

Pritchard was a pioneer in the study of the mechanical forces of light on atoms that lead to the Nobel Prize in physics in 1997 being awarded to Bill Phillips (his former postdoc), Steve Chu (a collaborator), and Claude Cohen-Tannoudji.  His group invented the widely used magneto-optical laser trap for neutral atoms and a high density variant called the dark spot MOT.  These traps are the workhorses in the field of cold atom research and, together with a magnetic atom trap Pritchard invented, have been used by many groups to attain and study Bose-Einstein condensation and other cold atom phenomena. Pritchard gave his cold atom research program to his postdoc Wolfgang Ketterle when he became as assistant professor at MIT. This resulted in the 2001 Nobel Prize in physics being awarded to Ketterle, who shared the prize with Pritchard’s former graduate student, Eric Cornell and Carl Wieman who was a Pritchard mentee as an undergraduate at MIT.  Four of Pritchard’s students, none of them yet Nobelists, have won national thesis awards.

Pritchard’s group pioneered the field of atom optics, in which quantum mechanical atom waves are manipulated like light waves in conventional optics.  They demonstrated diffraction gratings for atoms made from both standing waves of light and nanofabricated membranes.  The group used these gratings to make the first true atom interferometer.   Their atom interferometer addressed fundamental issues in quantum mechanics as demonstrated by their performing a thought experiment (gedankenexperiment) proposed by Feynman which probes the quantum decoherence due to scattering a single photon from an atom passing through the interferometer.  They also addressed issues in quantum decoherence and measured atomic and molecular properties and inertial rotation with sensitivity comparable to laser gyroscopes.  This group demonstrated phase coherent atom amplification in a collaboration with Ketterle’s, and developed confined atom interferometry by splitting Bose Einstein Condensates and subsequently recombining them.

Pritchard’s group has constructed the world’s most accurate mass spectrometer by measuring single trapped ions and subsequently trapping a single reference ion along with the ion to be massed.  Among other applications, it was used to recalibrate the gamma ray energy scale by weighing a gamma ray as well as to provide a new route to the most precise determination of the fine structure constant, alpha.  This experiment also led to the discovery of an important correction to the well-knows cyclotron frequency formula that is caused by the ion’s finite polarizability, and performed the most accurate test of E=mc2.

Pritchard’s group has made pioneering determinations of potentials for van der Waals molecules NaNe and KAr, these violate the rules you learned in high school chemistry that rare gases like Ne and Ar are chemically inert and do not form molecules.  The interaction potentials were determined both by scattering of ground state and laser-excited alkali atoms from the rare gas targets, and also by spectroscopy (laser and rf) on these molecules which were made by expanding high pressure gas into a vacuum.  Pritchard was a pioneer in the application of tunable lasers to physics and chemistry, being the first to demonstrate high resolution spectroscopy in which the system being studied absorbed two laser photons simultaneously.  His group also made measurements of atom-molecule collisions using the Doppler shift to select velocity and analyze scattering angles, and applied lasers to study atomic line broadening.

Pritchard’s professional activities have included Director, Interbuild Corporation (1968-1973), Director, Optical Society of America (1996-2000); Head, M.I.T. Physics-Industry Forum (1981-1984), (Organized 2 day Symposia in Optics for this in 1982 and 1989); Divisional Associate Editor, Phys. Rev. Lett. (1983- 1987); N.A.S. Committee on Atomic, Molecular, and Optical Science (1989-1992); and N.I.S.T. Visiting Committee for J.I.L.A. (1989-1993, chair 1994-1995).  He has served as American Physical Society representative to Joint Council on Quantum Electronics (1986-1992) and International Council on Quantum Electronics (1989-1992); APS Laser Science Topical Group Steering Committee (1988-1991); and within the Division of Atomic, Molecular, and Optical Physics has served on the Program Committee (1974-1977), (1981-1982), (1983-1985) (1989-1993), Publication Committee (1980-1983,1987, chairman 1988) Executive Committee (1988-1991), and Broida Prize Committee (Vice Chairman, Chairman 1983-1987, 1992). He has contributed to the organization of a number of scientific meetings including General Organizing Committee, International Conference on Collisions of Electron and Atomic Physics (1977-1981); Local Organizing Committee, International Conference on Atomic Physics (1980); Organizer (with H. Rabitz), Symposium on “Quantum Number Dependence of Cross Sections” @ Las Vegas, A.C.S. Meeting 3/30/82- 4/2/82; instigator and organizer of Workshop on Controlling Atoms, D.E.A.P. Meeting 5/28/84-5/29/84, Storrs, CT.; Co-Chairman of Program Committee (with C. Shank), International Quantum Electronics Conference ’87; Co-Chairman (with Arto Nurmikko), First Quantum Electronics and Laser Sciences Conference ’89, and program committees including a Nobel Symposium (1994), Gordon Conference (1991 & 93), Int’l Workshops on Atom Optics (1992-..) Int’l Conf. on Laser Physics (1995), Snowbird (1997).  Most recently he was the Chair of the International Conference on Atomic Physics (MIT 2002) and a founding lecturer at the associated Summer School.  He has  recently served on the AAPT committees for Research In Physics Education (2003-2006) Undergraduate Education (2007- 2010), and Educational Technology (2011- ).  He is a member of the National Research Committee on Undergraduate Physics Education.