Elihu Boldt, Physics Adjunct Professor, Dies at 77

Details

Category: Department News

Published: Tuesday, October 14 2008 13:52

Elihu A. Boldt, 77, a NASA astrophysicist who helped launch Goddard Space Flight Center's program in X-ray astronomy, died Sept. 12 at Doctors Community Hospital in Lanham after an apparent heart attack.

He was a Greenbelt resident and an adjunct physics professor at the University of Maryland. He was a fellow of the American Physical Society, among other professional affiliations, and served on scientific panels and committees.

For the full obituary:

http://www.washingtonpost.com/wp-dyn/content/article/2008/09/18/AR2008091803604.html

Richard E. Prange: 1932 - 2008

Details

Category: Department News

Published: Wednesday, October 01 2008 16:38

Prof. Richard E. Prange, a superb condensed matter theorist and great friend to many of us, died suddenly on Wednesday afternoon, Sept. 24, of an apparent heart attack. This is a great loss to our community, where Prof. Prange spent virtually his whole professorial career; he joined the department in 1961.

On September 23--his 76th birthday--he attended the physics colloquium; afterward he and Sankar Das Sarma had a vigorous discussion about that day's topic, the physics of graphene. Richard was his usual incisive self.

On Wednesday morning, he left Washington to drive to Philadelphia where his wife, Prof. Madeleine Joullié, is a Professor of Chemistry at the University of Pennsylvania. They maintained homes in both cities. En route, he stopped for an errand at a store in suburban Philadelphia. While at the store, he collapsed, and efforts to revive him were not successful.

Richard Prange loved the Department of Physics passionately, and was instrumental in its growth and strength during the past five decades. His cross-disciplinary intellectual breadth was a key to UMD physics becoming a top department in all areas of physics. His generosity and unfailing support were inspiring.

The Department hosted a memorial Tuesday, November 18, at 3:00p.m. in the West Chapel.

For more information please contact Anne Suplee at 301-405-5944 or This email address is being protected from spambots. You need JavaScript enabled to view it..

Condolences may be sent to Dr. M.Joullié, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104-6323 or This email address is being protected from spambots. You need JavaScript enabled to view it..

Plans are being formulated for a lasting tribute in Richard's memory, perhaps a fellowship or scholarship or some other means to support the department that he loved (and its students). Donations may be sent to the Physics Department, with checks made out to the University of Maryland College Park Foundation and designated for the “Department of Physics/in memory of Dr. Richard Prange". For inquiries, please contact the chair's office, 301-405-5946 or This email address is being protected from spambots. You need JavaScript enabled to view it..

Roald Sagdeev Elected to the American Philosophical Society

Details

Category: Department News

Published: Thursday, September 18 2008 09:00

Roald Sagdeev, Distinguished University Professor, has been elected a member of the American Philosophical Society. Election to the Society honors extraordinary accomplishments in all fields. Founded in 1745 by Benjamin Franklin, the APS has played an important role in American cultural and intellectual life for over 250 years.

"Spooky Action-at-a-Distance" with Individual Atoms

Details

Category: Research News

Published: Monday, September 15 2008 10:53

By: Christopher Monroe

Albert Einstein never liked Quantum Mechanics, with its fuzzy superpositions and confused states of reality. In 1935, he and colleagues Boris Podolsky and Nathan Rosen proposed a thought experiment that they believed would finally show cracks in the new quantum theory. The essentials of their famed proposal can be seen by cconsidering two “quantum coins,” that are prepared in a strange superposition of being both heads-up and both tails-up at the same time. When such coins are brought far apart from each other and then measured, quantum mechanics predicts that the only possible results can be HH and TT – the orientation of the coins always matches in perfect correlation. But when either individual coin is observed, its value is expected to be totally random (H or T). What’s interesting here is that while an individual coin is in an indeterminate state until observed, the observer immediately knows that orientation of the other coin, and this knowledge happens faster than the speed of light can traverse the distance between the coins.

Einstein called this quantum behavior “spooky action-at-a-distance,” and concluded that either quantum mechanics is incomplete, or it is just very weird. We now know, thanks to John Bell in 1964, that if quantum mechanics is indeed incomplete, than any more complete theory must be just as weird, so we might as well stick with quantum mechanics. Bell devised a measure of this weirdness: an inequality involving measured pair-correlations that is violated for situations like the one considered by Einstein, Podolsky and Rosen.

This weird type of quantum state the Einstein introduced is now known as an “entangled state,” and the spooky action-at-a-distance that he bemoaned is now the central resource in the field of Quantum Information Science. Replace the coins by quantum bits that can be in the state 0 and 1 simultaneously, and these qubits can be used for superfast computing applications, or fundamentally secure communication. Qubits are now being investigated in a variety of physical systems, from individual atoms and photons, to superconducting circuits and semiconductor quantum dots.

Recently, a team of researchers from the University of Maryland Department of Physics and Joint Quantum Institute have observed for the first time, quantum entanglement of individual atoms separated by a large distance [Moehring, et al., Nature 449, 68, (2007)]. Two atoms, held in electromagnetic traps one meter apart, were synchronized with a laser pulse, and the resulting emitted light was interfered on a beamsplitter and detected. This detection produced an entangled state of the two atoms, where qubits were stored in the magnetic orientation of each atom. This entanglement (the correlations of the atomic-scale magnets and the randomness of each one individually) was directly verified by measuring the magnetic orientation with a separate laser, resulting in a clear violation of Bell inequalities. This type of quantum linking between atomic qubits may ultimately lead to the fabrication of a large-scale quantum computer, where atomic memories will be able to store exponentially-rich amounts of data and be connected through optical interconnects as demonstrated here. In the nearer term, this is among the most promising roads to a “quantum repeater,” where qubits can be propagated over very large (or even geographic) distances with the use of optical fibers.