Steven Chu

Steven Chu (Chinese:朱棣文; pinyin: Zhū diwen; born February 28, 1948 in St. Louis, Missouri, USA) is an American physicist.

In 1997 he received the Nobel Prize for physics. His main field is the influence of atoms using lasers. He was director of the Lawrence Berkeley National Laboratory until his appointment as energy minister and holds professorships at Berkeley and Stanford.

In the cabinet of U.S. President Barack Obama Chu held from 2009 to 2013 the Office of the Secretary of Energy.


Chu comes from a family of academics Chinese descent who immigrated in 1943 by way of France to the United States. His father was a chemistry professor at Brooklyn Polytechnic, and Chu grew up near Garden City on. Chu initially studied at the University of Rochester, where he received his bachelors degree. He then moved to the University of California, Berkeley with the intention to specialize in theoretical physics. Instead he dealt with Eugene Commins with the measurement of parity violation of the (forbidden in quantum electrodynamics) magnetic dipole transition in thallium atoms that were possible after the electroweak theory in the standard model ( the original proposal for such experiments came from Claude Bouchiat and Marie -Anne Bouchiat in France 1974) and expressed in a weak asymmetry of the absorption right -and left- polarized light. For the experiment, Chu had to deal intensively with the construction of lasers. The experiment took some time to complete, and during that time he was a post-doc in 1976 - his experimental work was recognized as sufficient qualification. First results published the group in 1979, but at that time neutral currents were detected already at SLAC in high energy physics.

From 1978 he worked at Bell Laboratories in Murray Hill (New Jersey), where he began experiments to accurately measure the spectra of positronium, the " hydrogen atom " of quantum electrodynamics consisting of positron and electron. The experiment ( with Allen Mills ) was successful, but also took several years to complete. It was at that time one of the most accurate experiments on quantum electrodynamics.

In 1983 he was Head of the Department of Quantum Electronics Research of Bell Laboratories in Holmdel. At this time he planned to deal with Solid State Physics ( picosecond laser pulses for the study of exciton excitations), but was then ( inspired by work of his colleague Arthur Ashkin at Bell Labs, which it has since 1970 worked ) for the development of optical traps and its further out with laser cooling method for "capture" of atoms, which eventually earned him the Nobel Prize.

In 1987 he became the successor of Theodor Hänsch Professor of Physics and Applied Physics at Stanford University. There he directed from 1990 to 1993 and 1999 to 2001, the physics department and turned and biophysical research on.

In 2004 he became director of the Lawrence Berkeley National Laboratory and took this to a professorship at Berkeley. At Stanford, he is still out as a teacher, with the status on extended leave ( term of office).

Today he is a professor at the University of California, Berkeley. From 20 January 2009 to April 22, 2013 he was Secretary of Energy ( Secretary of Energy ) in the Obama administration.

In the speech to both houses of Congress on the occasion of the health reform in 2009 was Chu Designated Survivor. He would have been in case of an attack on the Capitol, the highest ranking survivor and the succession of Barack Obama would have joined the company as President. Chu was in 2013 in the State of the Union address again Designated Survivor.


Chu developed numerous methods and devices for optical and atomic physics measurements. So he measured using lasers, the parity violation in thallium atoms and with the Doppler free two-photon spectroscopy, he examined positronium and muonium ( with Mills, he measured in 1982 the difference between the 1s and 2s levels of positronium with an accuracy of a few parts in a billion ). His most important scientific achievement was the mid- 1980s, the laser cooling of atoms. It is a central component of magneto-optical atom traps.

Later Chu worked on refining these methods for atomic clocks after the fountain principle and Bose -Einstein condensates. He participated in high-precision measurements of the gravitational constant and the fine structure constant, and used some of his optical methods in biophysical studies, such as the manipulation of single DNA molecules with optical tweezers ( optical tweezers, 1989) or in the polymer dynamics.

1982, demonstrated the possibility of propagation of pulses in the absorbent media to a group velocity which is greater than the speed of light in the medium with Wong.

He was one of the first signatories of the petition for Project Steve, a campaign that advocates informing the conventional scientific view about the theory of evolution in schools and turned so popular in the U.S. against the alternative concepts of creationism and intelligent design.

Commitment to energy supply and climate change

Chu has long advocated an intensification of research in the field of renewable energies and the development of nuclear power, as he is of the opinion that a shift from fossil fuels is gone essential to combat global warming.

Chu also warned that global warming could make agriculture in the State of California impossible even within this century. He is a member of the Copenhagen Climate Council ( Copenhagen Climate Council ), an association of business and science representatives, which was created to give a boost to the UN Climate Change Conference in Copenhagen in December 2009.

Chu played an important role in the development of the successful bid for the Energy Biosciences Institute, a BP -funded $ 500 million joint project of the University of Berkeley, the Lawrence Berkeley Lab and the University of Illinois. This caused in Berkeley for a controversy with those who fear that such cooperation could damage the reputation of the university for academic integrity.

Awards and honors

Chu received the 1987 Broida Prize for laser spectroscopy of the American Physical Society, 1993 King Faisal Prize for Science and the 1995 Humboldt Research Award from the Alexander von Humboldt Foundation, which also a Wolfgang -Paul- lecture was organized, which he 1998 at the Physics Institute of the University of Bonn held. He is a member of the National Academy of Sciences.

In 1997, Chu, together with William D. Phillips and Claude Cohen-Tannoudji the Nobel Prize in Physics for the cool and trap atoms with laser light.