RSS icon
Twitter icon
Facebook icon
Vimeo icon
YouTube icon


March 10, 2017 | People News

Wellstood named new UMD Co-Director of JQI

Physics professor and JQI Fellow Fred Wellstood has been appointed the newest UMD Co-Director of JQI. He assumed the role on March 1."Fred has played a major role in the JQI since its founding," says Gretchen Campbell, the current NIST Co-Director of JQI. "Most recently, his tireless efforts helped to design and ultimately build the new Physical Sciences Center at Maryland that many JQI labs now call home. I look forward to working with him to carefully steward JQI’s future."Wellstood came to UMD in 1991 as an Assistant Professor of Physics after earning his Ph.D. from the University of California, Berkeley. Upon arriving, he joined the Center for Superconductivity Research, now known as the Center for Nanophysics and Advanced Materials, and began a fruitful research career studying experimental superconductivity with an eye toward the applications of superconducting quantum interference devices. He was Associate Chair for Undergraduate Education in the Department of Physics from 1999 to 2004 and helped add two new concentration tracks for physics majors at UMD—meteorology and physics education. Since then he has been intimately involved in revamping undergraduate lab offerings. Wellstood is a Fellow of the American Physical Society and holds nearly a dozen patents.He takes over from JQI Fellow Steve Rolston, who recently became Chair of the Department of Physics. Campbell applauds Rolston's five years of service as Co-Director of JQI. "JQI grew tremendously under Steve’s leadership," she says, "and his guidance helped enhance our leading role in basic quantum physics research. As Chair of the Department of Physics, he can continue to champion the efforts of JQI and the Department as a whole."
March 8, 2017 | PFC | Research News

Ions sync up into world's first time crystal

Consider, for a moment, the humble puddle of water. If you dive down to nearly the scale of molecules, it will be hard to tell one spot in the puddle from any other. You can shift your gaze to the left or right, or tilt your head, and the microscopic bustle will be identical—a situation that physicists call highly symmetric.That all changes abruptly when the puddle freezes. In contrast to liquid water, ice is a crystal, and it gains a spontaneous rigid structure as the temperature drops. Freezing fastens neighboring water molecules together in a regular pattern, and a simple tilt of the head now creates a kaleidoscopic change.In 2012, Nobel-prize winning physicist Frank Wilczek, a professor at the Massachusetts Institute of Technology, proposed something that sounds pretty strange. It might be possible, Wilczek argued, to create crystals that are arranged in time instead of space. The suggestion prompted years of false starts and negative results that ruled out some of the most obvious places to look for these newly named time crystals.Now, five years after the first proposal, a team of researchers led by physicists at the Joint Quantum Institute and the University of Maryland have created the world's first time crystal using a chain of atomic ions. The result, which finally brings Wilczek's exotic idea to life, was reported in Nature on March 9.
February 24, 2017 | People News

JQI graduate student named ARCS Endowment Fellow

Zachary Eldredge, a physics graduate student at JQI and QuICS, has been awarded an Endowment Fellowship by the Achievement Awards for College Scientists (ARCS) Foundation. The fellowship comes with $15,000 of financial support and is renewable. "I’m very thankful to the Foundation, as well as to the university for nominating me and helping me put together my application," Eldredge says. He will be honored at an awards reception at the National Academy of Science in October.The ARCS Foundation is a national organization dedicated to supporting STEM education in the United States. ARCS partners with more than 50 colleges and universities in 16 regional chapters across the country—including the Metropolitan Washington Chapter, through which Eldredge received his fellowship. Rather than soliciting applications, the ARCS Foundation allows its partner institutions to select some of their top students in science, engineering and medical research as candidates for the award. Since its inception in 1958, the Foundation has provided more than $100 million of financial support to thousands of scholars.Eldredge is a third year graduate student at JQI, having earned an undergraduate degree in physics from the University of Oklahoma in 2014. He currently works with JQI and QuICS Fellow Alexey Gorshkov on finding new ways to generate entanglement and use it as a quantum resource.
February 24, 2017 | PFC | Research News

Destabilized solitons perform a disappearing act

When your heart beats, blood courses through your veins in waves of pressure. These pressure waves manifest as your pulse, a regular rhythm unperturbed by the complex internal structure of the body. Scientists call such robust waves solitons, and in many ways they behave more like discrete particles than waves. Soliton theory may aid in the understanding of tsunamis, which—unlike other water waves—can sustain themselves over vast oceanic distances.Solitons can arise in the quantum world as well. At most temperatures, gas atoms bounce around like billiard balls, colliding with each other and rocketing off into random directions. Near absolute zero, however, certain kinds of atoms suddenly start behaving according to the very different rules of quantum mechanics, and begin a kind of coordinated dance. Under pristine conditions, solitons can emerge inside these ultracold quantum fluids, surviving for several seconds.Curious about how solitons behave in less than pristine conditions, scientists at NIST’s Physical Measurement Laboratory, in collaboration with researchers at the Joint Quantum Institute (JQI), have added some stress to a soliton’s life. They began by cooling down a cloud of rubidium atoms. Right before the gas became a homogenous quantum fluid, a radio-frequency magnetic field coaxed a handful of these atoms into retaining their classical, billiard ball-like state. Those atoms are, in effect, impurities in the atomic mix. The scientists then used laser light to push apart atoms in one region of the fluid, creating a solitary wave of low density—a “dark” soliton.
February 21, 2017 | Research News

Crossing the quantum-chaotic divide

Chaos is all around us, a fact that weather forecasters know all too well.Their job is notoriously difficult because small changes in air pressure or temperature, which ultimately drive winds and weather systems, can have huge consequences on a global scale. This sensitivity to tiny differences is commonly called the butterfly effect, and it makes weather patterns chaotic and hard to predict.Chaos pops up in many other places, too, and scientists have studied its role in physics for more than a century. But only since the 1980s have physicists investigated the connections between chaos and quantum mechanics—the most fundamental theory we have about the building blocks of the universe.One wrinkle in studying quantum chaos is that quantum physics itself seems to forbid chaotic behavior. The rules that govern the quantum world are actually too simple to give rise to the same kind of unpredictability as the weather. This prompted researchers to examine the differences between ordinary chaotic systems and their quantum counterparts more closely, a task that has been stalled because scientists lack the mathematical tools to quantify chaos in a quantum setting.Now, researchers from the Joint Quantum Institute (JQI) and the Condensed Matter Theory Center (CMTC) at the University of Maryland have used a promising diagnostic tool to characterize one of the simplest systems that physicists use to study chaos. This new diagnostic tracks the emergence of quantum interference effects and shows that they eventually destroy ordinary chaotic behavior. The work, performed by JQI and CMTC graduate student Efim Rozenbaum and two collaborators, was published online in Physical Review Letters on Feb. 21.
January 25, 2017 | Research News

Heads up, high school class of '19: New measurement unit definitions are coming

Next year, scientists expect to change the way we define the basic units with which we measure our universe. An article by scientists at the National Institute of Standards and Technology (NIST) written for teachers will help ensure high school physics students are hip to the news.The brief, six-page article, which appears in this month’s issue of The Physics Teacher, is designed to be a resource for teachers who are introducing the International System of Units (SI) into their classrooms. The SI, as the modern form of the metric system, has seven fundamental units, including the meter and the second. It is expected that in 2018, for the first time in history, all seven of these units will be defined in terms of fundamental constants of the universe such as the speed of light or the charge of a single electron. Only recently were all the relevant fundamental constants known with sufficient certainty to make such a redefinition possible, and the authors are eager to help students realize the change’s importance.
January 19, 2017 | PFC | Research News

Probe for nanofibers has atom-scale sensitivity

Optical fibers are the backbone of modern communications, shuttling information from A to B through thin glass filaments as pulses of light. They are used extensively in telecommunications, allowing information to travel at near the speed of light virtually without loss.These days, biologists, physicists and other scientists regularly use optical fibers to pipe light around inside their labs. In one recent application, quantum research labs have been reshaping optical fibers, stretching them into tiny tapers. For these nanometer-scale tapers, or nanofibers, the injected light still makes its way from A to B, but some of it is forced to travel outside the fiber’s exterior surface. The exterior light, or evanescent field, can capture atoms and then carry information about that light-matter interaction to a detector.Fine-tuning such evanescent light fields is tricky and requires tools for characterizing both the fiber and the light. To this end, researchers from JQI and the Army Research Laboratory (ARL) have developed a novel method to measure how light propagates through a nanofiber, allowing them to determine the nanofiber’s thickness to a precision less than the width of an atom. The technique, described in the January 20, 2017 issue of the journal Optica, is direct and fast, but also preserves the integrity of the fiber. 
December 21, 2016 | People News | Research News

A quantum year in review

If the looming holiday lull leaves you yearning for news from the quantum world, JQI has you covered. Below we present an overview of our major research and outreach activities from the past year, which marked JQI’s tenth anniversary.In 2016, JQI students, postdocs and Fellows published more than 120 academic papers, about half of which were enabled by the National Science Foundation's Physics Frontier Center at JQI. This year’s publications continued a strong record of scientific output and included work on an innovative quantum computer module powered by atomic ions, a potential application for an exotic new material and the dawning age of quantum machine learning, among many other topics. Many JQI scientists past and present received awards and honors recognizing their research and professional activities.  
December 6, 2016 | People News

CMTC to kick off annual research symposium

This week, the Condensed Matter Theory Center (CMTC) hosts its annual symposium, which brings attendees up to speed on the Center’s latest research interests. The symposium, which features 11 technical talks spanning two days, begins Dec. 7 and is open to all. This year’s talks cover a range of topics in condensed matter theory, reflecting the diverse interests of CMTC faculty, postdocs and students. These include Weyl semimetals, many-body localization and Majorana fermions—particles that played a leading role in a workshop that CMTC hosted at the end of October.  “CMTC wants to work on the most exciting frontier topics in the field because that’s what excites and enthuses the young researchers,” says Sankar Das Sarma, the director of CMTC and a JQI Fellow. CMTC, which has held a symposium every year since 2006, invites all of its members to present their latest work, provided that the results have been written up in a research paper.  The symposium follows on the heels of CMTC’s October Majorana workshop, which brought together nearly 40 experts on the physics of certain semiconductor-superconductor junctions. Attendees critically examined the experimental evidence for Majorana quasiparticles at the ends of nanowires in such systems, concluding that no other explanation of experimental results seems consistent. The quasiparticles predicted to live in these systems could be useful for building a future quantum computer. Das Sarma says that the workshop was a success and hopes that CMTC can host a similar meeting in future years. 
November 18, 2016 | People News

Das Sarma receives third consecutive honor as influential researcher

For the third year running, JQI Fellow and Distinguished University Professor of Physics Sankar Das Sarma has been identified as a Highly Cited Researcher. The annual distinction, previously compiled by Thomson Reuters IP & Science and now assembled by Clarivate Analytics, honors scientists who publish extensively and whose citation counts rank in the top 1 percent in a given year and field.Das Sarma, who is also the director of the Condensed Matter Theory Center at UMD, studies everything from exotic low-temperature materials to robust ways of building and operating future quantum computers. He has been regularly recognized for his prolific publication record, with similar honors dating back to 2001.A physics faculty member at UMD since 1980, Das Sarma received his undergraduate degree in physics in 1973 from Presidency College in Kolkata, India and his Ph.D. in theoretical physics in 1979 from Brown University.