Gerald Gabrielse

Gerald Gabrielse is an American physicist and the George Vasmer Leverett Professor of Physics at Harvard University. He is primarily known for his experiments trapping and investigating antimatter, measuring the electron g-factor,^[1] and measuring the electron electric dipole moment.^[2] He has been described as "a leader in super-precise measurements of fundamental particles and the study of anti-matter."^[3]

Career

Gabrielse attended Trinity Christian College and then Calvin College, graduating with a B.S. (honors) in 1973. He then completed his M.S. (1975) and Ph.D. (1980) in physics from the University of Chicago under Henry Gordon Berry. Gabrielse became a postdoc at the University of Washington in Seattle in 1978 under Hans Dehmelt,^[4] and joined the faculty in 1985. He became Professor of Physics at Harvard University in 1987, and the chair of the Harvard Physics Department in 2000. He is currently the George Vasmer Leverett Professor of Physics at Harvard.

In November 2015, it was announced that the Gabrielse group would be moving to Northwestern University in 2017 as part of the newly created Center for Fundamental Physics at Low Energy. Gabrielse will the first Director of the center.^[5]

Research

Antimatter research

Gabrielse was a pioneer in the field of low energy antiproton and antihydrogen physics by proposing the trapping of antiprotons from a storage ring, cooling them in collisions with trapped electrons,^[6] and the use of these to form low energy antihydrogen atoms.^[7] He led the TRAP team that realized the first antiproton trapping,^[8] the first electron cooling of trapped antiprotons, and the accumulation of antiprotons in a 4 Kelvin apparatus.^[9] The demonstrations and methods made possible an effort that grew to involve 4 international collaborations of physicists working at CERN's Antiproton Decelerator. In 1999, Gabrielse's TRAP team made the most precise test of the Standard Model's fundamental CPT theorem by comparing the charge-to-mass ratio of a single trapped antiproton with that of a proton to a precision of 9 parts in 10¹¹.^[10] The precision of the resulting confirmation of the Standard Model prediction exceeded that of earlier comparisons by nearly a factor of 10⁶.

Gabrielse now leads the ATRAP team at CERN, one of the two teams that first produced slow antihydrogen atoms and suspended them in a magnetic trap.^[11][12] Both TRAP and ATRAP teams used trapped antiprotons within a nested Penning trap device to produce antihydrogen atoms slow enough to be trapped in a magnetic trap. The team made the first one-particle comparison of the magnetic moments of a single proton and a single antiproton.^[13][14] Their comparison, to a precision of 5 parts per million, was 680 times more precision than previous measurements.^[15]

Precision measurement

In 2006, Gabrielse's group used a single trapped electron to measure the electron magnetic moment to 0.76 parts per trillion,^[16] which was 15 times more precise than a measurement that had stood for about 20 years.^[17] Two years later, the team improved the measurement uncertainty by a further factor of 3.^[1]

In 2014, Gabrielse, as part of the ACME collaboration with John Doyle at Harvard and David DeMille at Yale, measured the electron electric dipole moment to over an order of magnitude over the previous measurement using a beam of thorium monoxide,^[18] a result which had implications for the viability of supersymmetry.^[19]

Other research contributions

Gabrielse was also one of the discoverers of the Brown-Gabrielse invariance theorem,^[20] relating the free space cyclotron frequency to the measureable eigenfrequencies of an imperfect Penning trap. The theorem's applications include precise measurements of magnetic moments and precise mass spectrometry.^[21] It also makes sideband mass spectrometry possible, a standard tool of nuclear physics.^[22]

Gabrielse has also invented a self-shielding superconducting solenoid that uses flux conservation and a carefully chosen geometry of coupled coils to cancel strong field fluctuations due to external sources. The device was responsible for the success of the precise comparison of antiproton and proton, and also enables magnetic resonance imaging (MRI) systems to locate changing magnetic fields from external sources, such as elevators.^[23]

Religious views

Gabrielse identifies himself as a scientist who is Reformed Christian. In an interview, he said:

I do not believe that science and the Bible are in conflict. However, it is possible to misunderstand the Bible and to misunderstand science. It is important to figure out what of each might be misunderstood.^[24]

He has also delivered lectures on the relation between science and religion. In 2006 Gabrielse delivered a lecture titled "God of Antimatter" in the Faraday Institute for Science and Religion in Emmanuel College, Cambridge, discussing his research into antimatter as well as his personal experience with Christianity.^[25] He was awarded the Trotter Prize in 2013 and gave the Trotter Lecture for that year.^[26]

Trivia

• On an episode of Late Night with Conan O'Brien that aired on February 21, 2007, Jim Carrey and Conan O'Brien humorously discussed content from a paper entitled, "Stochastic Phase-Switching of a Parametrically-Driven Electron in a Penning Trap"^[27] Gerald Gabrielse said that it was 'perhaps the most obscure paper I've ever written'.^[28]
• Working at CERN, Gabrielse trapped the first antiprotons in 1986. Dan Brown's subsequent novel Angels & Demons, and the movie made from it, use antimatter trapped at CERN as an important plot point.

Awards

• Fellow of the American Physical Society (1992)
• Distinguished Alumnus Award, Trinity College (1999)
• Levenson Prize for Excellence in the Education of Undergraduates, Harvard University (2000)
• Davisson-Germer Prizeof the American Physical Society (2002)^[29]
• George Ledlie Prize, Harvard University (2004)
• Humboldt Research Award, Germany (2005)
• Distinguished Alumni Award, Calvin College (2006)^[30]
• Inducted into the National Academy of Sciences (2007)^[31]
• Källén Lecturer, Lund, Sweden (2007)
• William H. Zachariasen Lecturer at the University of Chicago (2007-2008)
• Poincaré Lecturer, Paris (2007)
• Premio Caterina Tomassoni and Felice Pietro Chisesi Prize, Italy (2008)
• Julius Edgar Lilienfeld Prize of the American Physical Society (2011)
• Trotter Prize, Texas A&M University (2013)^[26]

References

External links

• Scientific publications of Gerald Gabrielse on INSPIRE-HEP