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August 20, 2016 | People News

Remembering Katharine Blodgett Gebbie 1932-2016

See also NIST official obituary with video tribute and interviewThe members of the JQI join many in saying farewell and paying tribute to their esteemed colleague. Katharine Gebbie spent her career at the National Institute of Standards and Technology (NIST) and was the Director of the Physics and Physical Measurement Laboratories, where she oversaw the work that led to four Nobel Prizes in Physics (William Phillips, Eric Cornell, Jan Hall, and David Wineland). This achievement was directly due to her management style, which placed the science and scientists above all else.
August 3, 2016 | PFC | Research News

Programmable ions set the stage for general-purpose quantum computers

Quantum computers promise speedy solutions to some difficult problems, but building large-scale, general-purpose quantum devices is a problem fraught with technical challenges.To date, many research groups have created small but functional quantum computers. By combining a handful of atoms, electrons or superconducting junctions, researchers now regularly demonstrate quantum effects and run simple quantum algorithms—small programs dedicated to solving particular problems.But these laboratory devices are often hard-wired to run one program or limited to fixed patterns of interactions between their quantum constituents. Making a quantum computer that can run arbitrary algorithms requires the right kind of physical system and a suite of programming tools. Atomic ions, confined by fields from nearby electrodes, are among the most promising platforms for meeting these needs.In a paper published as the cover story in Nature on August 4, researchers working with Christopher Monroe, a Fellow of the Joint Quantum Institute and the Joint Center for Quantum Information and Computer Science at the University of Maryland, introduced the first fully programmable and reconfigurable quantum computer module. The new device, dubbed a module because of its potential to connect with copies of itself, takes advantage of the unique properties offered by trapped ions to run any algorithm on five quantum bits, or qubits—the fundamental unit of information in a quantum computer.
August 3, 2016 | PFC | People News

Federal report urges commitment to quantum research

A government report, authored by experts from a variety of federal agencies, has recommended that the US treat quantum information science as a national priority.
June 24, 2016 | PFC | Research News

Ultra-cold atoms may wade through quantum friction

Theoretical physicists studying the behavior of ultra-cold atoms have discovered a new source of friction, dispensing with a century-old paradox in the process. Their prediction, which experimenters may soon try to verify, was reported recently in Physical Review Letters.The friction afflicts certain arrangements of atoms in a Bose-Einstein Condensate (BEC), a quantum state of matter in which the atoms behave in lockstep. In this state, well-tuned magnetic fields can cause the atoms to attract one another and even bunch together, forming a single composite particle known as a soliton.
June 6, 2016 | PFC | Research News

Disorder grants a memory to quantum spins

Nature doesn’t have the best memory. If you fill a box with air and divide it in half with a barrier, it’s easy to tell molecules on the left from molecules on the right. But after removing the barrier and waiting a short while, the molecules get mixed together, and it becomes impossible to tell where a given molecule started. The air-in-a-box system loses any memory of its initial conditions.The universe has been forgetting its own initial state since the Big Bang, a fact linked to the unrelenting forward march of time. Systems that forget where they started are said to have thermalized, since it is often—but not always—an exchange of heat and energy with some other system that causes the memory loss. For example, a melting ice cube forgets its orderly arrangement of water molecules when heat from its surroundings splits the cube’s crystal bonds. In some sense, the initial information about the ice cube—the structure of the crystal, the distance between molecules, etc.—leaks away.The opposite case is localization, where information about the initial arrangement sticks around. Such a situation is rare, like an ice cube that never melts, but one example is Anderson localization, in which particles or waves in a crystal are trapped near impurities. They tend to bounce off defects in the crystal and scatter in random directions, yielding no net movement. If there are enough impurities in a region, the particles or waves never escape.Since the discovery of Anderson localization in 1958, it has been an open question whether interacting collections of quantum particles can also localize, a phenomenon known as many-body localization. Now, researchers working with JQI and QuICS Fellow Christopher Monroe have directly observed this localization in a system of 10 interacting ions, trapped and zapped by electric fields and lasers. Their findings are one of the first direct observations of many-body localization in a quantum system, and they open up the possibility of studying the phenomenon with more ions. The results were published June 6 in Nature Physics.
May 23, 2016 | People News

JQI researchers attend 47th DAMOP meeting in Providence

Dozens of JQI Fellows, postdoctoral researchers and graduate students are in Providence, R.I. this week for the 47th meeting of the American Physical Society's Division of Atomic, Molecular and Optical Physics (DAMOP). They will be delivering talks and posters on everything from the anomalous behavior of driven Rydberg atoms to running quantum algorithms in a programmable system of trapped ions. A session of invited talks given by three winners of DAMOP prizes is scheduled for Tuesday morning. It will be closed out by the 2015 Maria Goeppert Mayer Award winner, JQI Co-Director Gretchen Campbell, who will talk about her work on superfluid atom circuits.Check out a full list of JQI contributions by using the "Affiliation Search" at the DAMOP meeting online program.
May 23, 2016 | PFC | Research News

Quantum cycles power cold-atom pump

The idea of a pump is at least as old as the ancient Greek philosopher and scientist Archimedes. More than 2000 years ago, Archimedes allegedly invented a corkscrew pump that could lift water up an incline with the turn of a handle. Versions of the ancient invention still bear his name and are used today in agriculture and industry.Modern pumps have achieved loftier feats. For instance, in the late 1990s, NIST developed a device that could pump individual electrons, part of a potential new standard for measuring capacitance.While pumps can be operated mechanically, electrically or via any other source of energy, they all share the common feature of being driven by a periodic action. In the Archimedean pump, that action is a full rotation of the handle, which draws up a certain volume of water. For the NIST electron pump, it is a repeating pattern of voltage signals, which causes electrons to hop one at a time between metallic islands.But physicists have sought for decades to build a different kind of pump—one driven by the same kind of periodic action but made possible only by the bizarre rules of quantum mechanics. Owing to their physics, these pumps would be immune to certain imperfections in their fabrication.Now, a team of physicists working in collaboration with JQI Fellow Ian Spielman and NIST postdoctoral researcher Hsin-I Lu has created just such a pump. By periodically jostling many individual atoms, the researchers were able to shift an entire atomic cloud without any apparent overall motion by its constituents. The team is the first to test this predicted behavior, which arises in what they call a geometric charge pump. The work follows close on the heels of two recent papers that examined topological charge pumps, which demonstrate a distinct but related effect. The new result was published May 20 in Physical Review Letters.
May 10, 2016 | Research News

Novel gate may enhance power of Majorana-based quantum computers

Quantum computers hold great potential, but they remain hard to build because their basic components—individual quantum systems like atoms, electrons or photons—are fragile. A relentless and noisy background constantly bombards the computer’s data. One promising theoretical approach, known as topological quantum computing, uses groups of special particles confined to a plane to combat this environmental onslaught. The particles, which arise only in carefully crafted materials, are held apart from each other so that the information they store is spread out in space. In this way, information is hidden from its noisy environment, which tends to disrupt small regions at a time. Such a computer would perform calculations by moving the particles around one another in a plane, creating intricate braids with the paths they trace in space and time. Although evidence for these particles has been found in experiments, the most useful variety found so far appear only at the ends of tiny wires and cannot easily be braided around one another. Perhaps worse for the prospect of quantum computing is that these particles don’t support the full power of a general quantum computer—even in theory. Now, researchers at JQI and the Condensed Matter Theory Center (CMTC) at the University of Maryland, including JQI Fellows Sankar Das Sarma and Jay Deep Sau, have proposed a way to dispense with both of these problems. By adding an extra process beyond ordinary braiding, they discovered a way to give a certain breed of topological particles all the tools needed to run any quantum calculation, all while circumventing the need for actual braiding. The team described their proposal last month in Physical Review X.
May 3, 2016 | People News

Christopher Monroe elected to National Academy of Sciences

University of Maryland Physics Professor Christopher Monroe has been elected to the National Academy of Sciences. Monroe, who is also a Distinguished University Professor, the Bice Zorn Professor of Physics, and a fellow of the Joint Quantum Institute and the Joint Center for Quantum Information and Computer Science, is one of 84 new members and 21 foreign associates elected in 2016. He joins a select group of 2,291 scientists around the country elected by their peers and recognized for their influential research. He is a scientific leader in trapping atomic ions and studying how to use their quantum properties for information processing.