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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.
November 17, 2016 | People News

Luis Orozco receives honorary doctorate from INAOE

JQI Fellow Luis Orozco received an honorary doctorate from INAOE, Instituto Nacional de Astrofisica, Optica y Electronica. INAOE is a public research center sponsored by the National Council of Science and Technology of Mexico. Orozco accepted the award on November 11, 2016 at a ceremony in Mexico marking the INAOE's 45th anniversary. An announcement accompanying the ceremony, which lauds Orozco's extensive collaboration with the Mexican scientific community and notes his dedication to mentoring students, is available  on the institute's site. 
November 14, 2016 | PFC | Research News

Atomic beltway could solve problems of cosmic gravity

When is a traffic jam not a traffic jam? When it's a quantum traffic jam, of course. Only in quantum physics can traffic be standing still and moving at the same time. A new theoretical paper from scientists at the National Institute of Standards and Technology (NIST) and the University of Maryland suggests that intentionally creating just such a traffic jam out of a ring of several thousand ultracold atoms could enable precise measurements of motion. If implemented with the right experimental setup, the atoms could provide a measurement of gravity, possibly even at distances as short as 10 micrometers—about a tenth of a human hair's width.
October 28, 2016 | People News | Research News

Artificial atoms shed light on the future of security

From credit card numbers to bank account information, we transmit sensitive digital information over the internet every day. Since the 1990s, though, researchers have known that quantum computers threaten to disrupt the security of these transactions. That’s because quantum physics predicts that these computers could do some calculations far faster than their conventional counterparts. This would let a quantum computer crack a common internet security system called public key cryptography. This system lets two computers establish private connections hidden from potential hackers. In public key cryptography, every device hands out copies of its own public key, which is a piece of digital information.  Any other device can use that public key to scramble a message and send it back to the first device. The first device is the only one that has another piece of information, its private key, which it uses to decrypt the message. Two computers can use this method to create a secure channel and send information back and forth. A quantum computer could quickly calculate another device’s private key and read its messages, putting every future communication at risk. But many scientists are studying how quantum physics can fight back and help create safer communication lines.
October 20, 2016 | Research News

Move over, lasers: Scientists can now create holograms using neutrons

For the first time, a team including scientists from the National Institute of Standards and Technology (NIST) and JQI have used neutron beams to create holograms of large solid objects, revealing their interior details in ways that ordinary holograms do not.Holograms—flat images that look like three-dimensional objects—owe their striking look to interfering waves. Both matter and light behave like waves at the smallest scales, and just like water waves traveling on the surface of the pond, waves of matter or light can combine to create information-rich interference patterns.Illuminating an object with a laser can create an optical hologram. But instead of merely photographing the light reflected from the object, a hologram records how the reflected light waves interfere with each other. The resulting patterns, based on the waves’ phase differences, or relative positions of their peaks and valleys, contain far more information about an object’s appearance than a simple photo. Generally, though, they don’t reveal much about its interior.
October 14, 2016 | PFC | Research News

A closer look at Weyl physics

The 2015 discovery of a Weyl semimetal—and the Weyl fermions it harbored—provoked a flurry of activity from researchers around the globe. A quick glance at a recent physics journal or the online arXiv preprint server testifies to the topic’s popularity. The arXiv alone has had more than 200 papers on Weyl semimetals posted in 2016.Researchers at JQI and the Condensed Matter Theory Center (CMTC) at the University of Maryland have been interested in Weyl physics since before last summer’s discovery, publishing 18 papers on the topic over the past two years. In all, more than a dozen scientists at Maryland have been working to understand the fundamental properties of these curious new materials.