Wolfgang Ketterle

Last updated
Wolfgang Ketterle
Wolfgang Ketterle at a symposium at Brown University, 2007
Born (1957-10-21) 21 October 1957 (age 62)
NationalityGermany, United States
Alma mater Heidelberg
Max Planck Institute of Quantum Optics
Known for Bose–Einstein condensates
Awards Benjamin Franklin Medal (2000)
Nobel Prize for Physics (2001)
Scientific career
Fields Physics
Institutions University of Heidelberg
Doctoral advisor Herbert Walther
Hartmut Figger
Doctoral students Kendall B. Davis
Marc-Oliver Mewes
Dan Stamper-Kurn
Martin Zwierlein

Wolfgang Ketterle (born 21 October 1957) is a German physicist and professor of physics at the Massachusetts Institute of Technology (MIT). His research has focused on experiments that trap and cool atoms to temperatures close to absolute zero, [1] and he led one of the first groups to realize Bose–Einstein condensation in these systems in 1995. [2] For this achievement, as well as early fundamental studies of condensates, he was awarded the Nobel Prize in Physics in 2001, together with Eric Allin Cornell and Carl Wieman. [3]



Ketterle was born in Heidelberg, Baden-Württemberg, and attended school in Eppelheim and Heidelberg. [4] In 1976 he entered the University of Heidelberg, before transferring to the Technical University of Munich two years later, where he gained the equivalent of his master's diploma in 1982. [4] [5] In 1986 he earned a PhD in experimental molecular spectroscopy under the supervision of Herbert Walther and Hartmut Figger at the Max Planck Institute for Quantum Optics in Garching, before conducting postdoctoral research at Garching and the University of Heidelberg. [5] In 1990 he joined the group of David E. Pritchard in the Research Laboratory of Electronics at MIT (RLE). [4] He was appointed to the MIT physics faculty in 1993 and, since 1998, he has been John D. MacArthur Professor of Physics. [5] In 2006, he was appointed Associate Director of RLE and began serving as director of MIT's Center for Ultracold Atoms. [5]

After achieving Bose–Einstein condensation in dilute gases in 1995, his group was in 1997 able to demonstrate interference between two colliding condensates, [6] as well as the first realization of an "atom laser", the atomic analogue of an optical laser. [7] In addition to ongoing investigations of Bose–Einstein condensates in ultracold atoms, his more recent achievements have included the creation of a molecular Bose condensate in 2003, [8] as well as a 2005 experiment providing evidence for "high-temperature" superfluidity in a fermionic condensate. [9]

Ketterle is also a runner, and was featured in the December 2009 issue of Runner's World's "I'm a Runner". [10] Ketterle spoke of taking his running shoes to Stockholm when he received the Nobel Prize and happily running in the early dusk. Ketterle completed the 2013 Boston Marathon with a time of 2:49:16, [11] and in 2014, in Boston, ran a personal record of 2:44:06.

Ketterle serves on the Board of Trustees of the Center for Excellence in Education (CEE), [12] and participates in the Distinguished Lecture Series of CEE's flagship program for high-school students, the Research Science Institute (RSI), which Ketterle's own son Jonas attended in 2003. Ketterle sits on the International Scientific Advisory Committee of Australia's ARC Centre of Excellence in Future Low-Energy Electronics Technologies. [13]

Ketterle is one of the 20 American recipients of the Nobel Prize in Physics to sign a letter addressed to President George W. Bush in May of 2008, urging him to "reverse the damage done to basic science research in the Fiscal Year 2008 Omnibus Appropriations Bill" by requesting additional emergency funding for the Department of Energy’s Office of Science, the National Science Foundation, and the National Institute of Standards and Technology. [14]

Personal life

Since 2011, Ketterle has been married to Michèle Plott. He has five children, three with Gabriele Ketterle, to whom he was married from 1985 to 2001. [4]


Related Research Articles

Bose–Einstein condensate state of matter of a dilute gas of bosons cooled to temperatures very near absolute zero

A Bose–Einstein condensate (BEC) is a state of matter which is typically formed when a gas of bosons at low densities is cooled to temperatures very close to absolute zero (-273.15 °C). Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which point microscopic quantum phenomena, particularly wavefunction interference, become apparent macroscopically. A BEC is formed by cooling a gas of extremely low density, about one-hundred-thousandth (1/100,000) the density of normal air, to ultra-low temperatures.

Laser cooling Cooling techniques involving lasers

Laser cooling includes a number of techniques in which atomic and molecular samples are cooled down to near absolute zero. Laser cooling techniques rely on the fact that when an object absorbs and re-emits a photon its momentum changes. For an ensemble of particles, their thermodynamic temperature is proportional to the variance in their velocity. That is, more homogeneous velocities among particles corresponds to a lower temperature. Laser cooling techniques combine atomic spectroscopy with the aforementioned mechanical effect of light to compress the velocity distribution of an ensemble of particles, thereby cooling the particles.

Carl Wieman Nobel prize winning US physicist

Carl Edwin Wieman is an American physicist and educationist at Stanford University. In 1995, while at the University of Colorado Boulder, he and Eric Allin Cornell produced the first true Bose–Einstein condensate (BEC) and, in 2001, they and Wolfgang Ketterle were awarded the Nobel Prize in Physics. Wieman currently holds a joint appointment as Professor of Physics and Professor in the Stanford Graduate School of Education, as well as the DRC Professor in the Stanford University School of Engineering.

Eric Allin Cornell American physicist

Eric Allin Cornell is an American physicist who, along with Carl E. Wieman, was able to synthesize the first Bose–Einstein condensate in 1995. For their efforts, Cornell, Wieman, and Wolfgang Ketterle shared the Nobel Prize in Physics in 2001.

Supersolid spatially ordered material with superfluid properties

A supersolid is a spatially ordered material with superfluid properties. In the case of helium-4, it has been conjectured since the 1960s that it might be possible to create a supersolid. Starting from 2017, a definitive proof for the existence of this state was provided by several experiments using atomic Bose-Einstein condensates. The general conditions required for supersolidity to emerge in a certain substance are a topic of ongoing research.

Deborah S. Jin American physicist

Deborah Shiu-lan Jin was an American physicist and fellow with the National Institute of Standards and Technology (NIST); Professor Adjunct, Department of Physics at the University of Colorado; and a fellow of the JILA, a NIST joint laboratory with the University of Colorado.

Lene Hau Danish physicist

Lene Vestergaard Hau is a Danish physicist who is currently the Mallinckrodt Professor of Physics and of Applied Physics at Harvard University. She received a PhD from Aarhus University. In 1999, she led a Harvard University team who, by use of a Bose–Einstein condensate, succeeded in slowing a beam of light to about 17 metres per second, and, in 2001, was able to stop a beam completely. Later work based on these experiments led to the transfer of light to matter, then from matter back into light, a process with important implications for quantum encryption and quantum computing. More recent work has involved research into novel interactions between ultracold atoms and nanoscopic-scale systems. In addition to teaching physics and applied physics, she has taught Energy Science at Harvard, involving photovoltaic cells, nuclear power, batteries, and photosynthesis. As well as her own experiments and research, she is often invited to speak at international conferences, and is involved in structuring the science policies of various institutions. She was keynote speaker at EliteForsk-konferencen 2013 in Copenhagen, which was attended by government ministers, as well as senior science policy and research developers in Denmark. In acknowledgment of her many achievements, Discover Magazine recognized her in 2002 as one of the 50 most important women in science.

Rudolf Grimm Austrian physicist

Rudolf Grimm is an experimental physicist from Austria. His work centres on ultracold atoms and quantum gases. He was the first scientist worldwide who, with his team, succeeded in realizing a Bose–Einstein condensation of molecules.

An atom laser is a coherent state of propagating atoms. They are created out of a Bose–Einstein condensate of atoms that are output coupled using various techniques. Much like an optical laser, an atom laser is a coherent beam that behaves like a wave. There has been some argument that the term "atom laser" is misleading. Indeed, "laser" stands for "Light Amplification by Stimulated Emission of Radiation" which is not particularly related to the physical object called an atom laser, and perhaps describes more accurately the Bose–Einstein condensate (BEC). The terminology most widely used in the community today is to distinguish between the BEC, typically obtained by evaporation in a conservative trap, from the atom laser itself, which is a propagating atomic wave obtained by extraction from a previously realized BEC. Some ongoing experimental research tries to obtain directly an atom laser from a "hot" beam of atoms without making a trapped BEC first.

Magneto-optical trap device in physics to trap atoms in vacuum

A magneto-optical trap (MOT) is an apparatus that uses laser cooling with magneto-optical trapping in order to produce samples of cold, trapped, neutral atoms at temperatures as low as several microkelvins, two or three times the recoil limit . By combining the small momentum of a single photon with a velocity and spatially dependent absorption cross section and many absorption-spontaneous emission cycles, atoms with initial velocities of hundreds of metres per second can be slowed to tens of centimetres per second.

Daniel Kleppner, born 1932, is the Lester Wolfe Professor Emeritus of Physics at MIT and co-director of the MIT-Harvard Center for Ultracold Atoms. His areas of science include Atomic, Molecular, and Optical Physics, and his research interests include Experimental Atomic Physics, Laser Spectroscopy, and High Precision Measurements. He is the winner of the 2005 Wolf Prize in Physics, the 2007 Frederic Ives Medal, and the 2014 Benjamin Franklin Medal. Prof. Kleppner has also been awarded the National Medal of Science (2006). Together with Robert J. Kolenkow, he authored a popular introductory mechanics textbook for advanced students. Kleppner graduated from Williams College with a B.A. in 1953, Cambridge University with a B.A. in 1955, and Harvard University with a Ph.D. in 1959.

Ultracold atoms are atoms that are maintained at temperatures close to 0 kelvin, typically below several tens of microkelvin (µK). At these temperatures the atom's quantum-mechanical properties become important.

David Edward Pritchard is physics professor at the Massachusetts Institute of Technology (MIT). Professor Pritchard carried out pioneering experiments on the interaction of atoms with light that led to the creation of the field of atom optics. His demonstration of the diffraction of a beam of atoms by a grating made of light waves opened the way to studies of the diffraction, reflection, and focusing of matter waves, similar to those with light waves. He has applied atom optics to basic studies of quantum theory, to new methods for studying the properties of atoms, and to the creation of devices such as the atom interferometer and atom wave gyroscope.

Jook Walraven Dutch physicist

Joannes Theodorus Maria (Jook) Walraven is a Dutch experimental physicist at the Van der Waals-Zeeman Institute for experimental physics in Amsterdam. From 1967 he studied physics at the University of Amsterdam. Both his doctoral research and PhD research was with Isaac Silvera, on the subject of Bose-Einstein Condensation. Because of the difficulty of his research subject, his promotion took six years instead of four. The aim of his PhD research was to make a gas of atomic hydrogen, which could become the world's first quantum gas. This might then be a suitable candidate for a Bose-Einstein condensate (BEC).

The MIT School of Science is one of the five schools of the Massachusetts Institute of Technology, located in Cambridge, Massachusetts, United States. The School is composed of 6 academic departments who grant SB, SM, and PhD or ScD degrees; as well as a number of affiliated laboratories and centers. As of 2019, the Dean of Science is Professor Michael Sipser. With approximately 275 faculty members, 1100 graduate students, 700 undergraduate majors, 500 postdocs, and 400 research staff, the School is the second largest at MIT. As of 2019, 12 faculty members and 14 alumni of the School have won Nobel Prizes.

Superfluidity Non-classical state of matter

Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy. When stirred, a superfluid forms vortices that continue to rotate indefinitely. Superfluidity occurs in two isotopes of helium when they are liquefied by cooling to cryogenic temperatures. It is also a property of various other exotic states of matter theorized to exist in astrophysics, high-energy physics, and theories of quantum gravity. Superfluidity is often coincidental with Bose–Einstein condensation, but neither phenomenon is directly related to the other; not all Bose-Einstein condensates can be regarded as superfluids, and not all superfluids are Bose–Einstein condensates. The semiphenomenological theory of superfluidity was developed by Lev Landau.

Bose–Einstein condensation can occur in quasiparticles, particles that are effective descriptions of collective excitations in materials. Some have integer spins and can be expected to obey Bose–Einstein statistics like traditional particles. Conditions for condensation of various quasiparticles have been predicted and observed. The topic continues to be an active field of study.

Bose–Einstein condensation of polaritons is a growing field in semiconductor optics research, which exhibits spontaneous coherence similar to a laser, but through a different mechanism. A continuous transition from polariton condensation to lasing can be made similar to that of the crossover from a Bose–Einstein condensate to a BCS state in the context of Fermi gases. Polariton condensation is sometimes called “lasing without inversion”.

Spinor condensates are degenerate Bose gases that have degrees of freedom arising from the internal spin of the constituent particles . They are described by a multi-component (spinor) order parameter. Since their initial experimental realisation, a wealth of studies have appeared, both experimental and theoretical, focusing on the physical properties of spinor condensates, including their ground states, non-equilibrium dynamics, and vortices.

Crispin Gardiner New Zealand physicist

Crispin Gardiner is a New Zealand physicist, who has worked in the fields of Quantum Optics, Ultracold Atoms and Stochastic Processes. He has written about 120 journal articles and several books in the fields of quantum optics, stochastic processes and ultracold atoms


  1. "Wolfgang Ketterle". MIT Department of Physics. Retrieved 27 October 2014.
  2. Shachtman, Tom (January 2008). "The Coldest Place in the Universe". Smithsonian Magazine. Retrieved 27 October 2014.
  3. "Nobel Prize in Physics 2001". Nobelprize.org. Nobel Media. Retrieved 27 October 2014.
  4. 1 2 3 4 "Wolfgang Ketterle - Biographical". Nobelprize.org. Nobel Media. Retrieved 27 October 2014.
  5. 1 2 3 4 "Curriculum Vitae - Wolfgang Ketterle" (PDF). Alkali BEC Projects @ MIT. Archived from the original (PDF) on 26 April 2015. Retrieved 27 October 2014.
  6. "Interference of Two Condensates". Alkali BEC Projects @ MIT. Archived from the original on 4 March 2016. Retrieved 27 October 2014.
  7. Ketterle, Wolfgang (20 November 2002). "Nobel lecture: When atoms behave as waves: Bose-Einstein condensation and the atom laser" (PDF). Reviews of Modern Physics. 74 (4): 1131–51. Bibcode:2002RvMP...74.1131K. doi:10.1103/revmodphys.74.1131 . Retrieved 27 October 2014.
  8. "Physicists perform ultracold coup over molecules". MIT News. 18 December 2003. Retrieved 27 October 2014.
  9. "High-Temperature Superfluidity". Atomic Quantum Gases @ MIT. Archived from the original on 8 September 2015. Retrieved 27 October 2014.
  10. Doucleff, Michaeleen (3 November 2009). "I'm A Runner: Wolfgang Ketterle, Ph.D." Runner's World. Retrieved 27 October 2014.
  11. "2013 Boston Marathon Top Finishers". registration.baa.org. Retrieved 27 October 2014.
  12. "Board of Trustees". Center for Excellence in Education. Retrieved 27 October 2014.
  13. "Prof Ketterle biography". Centre for Future Low-Energy Electronics Technologies. Retrieved 9 November 2017.
  14. "A Letter from America's Physics Nobel Laureates" (PDF).