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March 6, 2019 | PFC | Research News

Ion experiment aces quantum scrambling test

Researchers at the Joint Quantum Institute have implemented an experimental test for quantum scrambling, a chaotic shuffling of the information stored among a collection of quantum particles. Their experiments on a group of seven atomic ions, reported in the March 7 issue of Nature, demonstrate a new way to distinguish between scrambling—which maintains the amount of information in a quantum system but mixes it up—and true information loss. The protocol may one day help verify the calculations of quantum computers, which harness the rules of quantum physics to process information in novel ways. 
February 1, 2019 | PFC | Research News

Glass fibers and light offer new control over atomic fluorescence

Electrons inside an atom whip around the nucleus like satellites around the Earth, occupying orbits determined by quantum physics. Light can boost an electron to a different, more energetic orbit, but that high doesn’t last forever. At some point the excited electron will relax back to its original orbit, causing the atom to spontaneously emit light that scientists call fluorescence.   Scientists can play tricks with an atom’s surroundings to tweak the relaxation time for high-flying electrons, which then dictates the rate of fluorescence. In a new study, researchers at the Joint Quantum Institute observed that a tiny thread of glass, called an optical nanofiber, had a significant impact on how fast a rubidium atom releases light. The research, which appeared as an Editor’s Suggestion in Physical Review A, showed that the fluorescence depended on the shape of light used to excite the atoms when they were near the nanofiber.
December 20, 2018 | PFC | Research News

Cold atoms offer a glimpse of flat physics

These days, movies and video games render increasingly realistic 3-D images on 2-D screens, giving viewers the illusion of gazing into another world. For many physicists, though, keeping things flat is far more interesting.One reason is that flat landscapes can unlock new movement patterns in the quantum world of atoms and electrons. For instance, shedding the third dimension enables an entirely new class of particles to emerge—particles that that don’t fit neatly into the two classes, bosons and fermions, provided by nature. These new particles, known as anyons, change in novel ways when they swap places, a feat that could one day power a special breed of quantum computer.But anyons and the conditions that produce them have been exceedingly hard to spot in experiments. In a pair of papers published this week in Physical Review Letters, JQI Fellow Alexey Gorshkov and several collaborators proposed new ways of studying this unusual flat physics, suggesting that small numbers of constrained atoms could act as stand-ins for the finicky electrons first predicted to exhibit low-dimensional quirks.
November 30, 2018 | Research News

Researchers see signs of interactive form of quantum matter

News from NIST Researchers at JILA have, for the first time, isolated groups of a few atoms and precisely measured their multi-particle interactions within an atomic clock. They compared the results with theoretical predictions by NIST colleagues Ana Maria Rey and Paul Julienne and concluded that multi-particle interactions occurred."This experiment demonstrates a remarkable ability to both measure and calculate the quantum properties of just a handful of atoms held in single optical lattice cells,” says Julienne, who is also a JQI Fellow. "This type of setup is a superb platform for precision measurement and for controlling many-particle quantum dynamics and entanglement, with applications to few-body physics, many-body physics, and quantum information.”The advance will help scientists control interacting quantum matter, which is expected to boost the performance of atomic clocks, many other types of sensors, and quantum information systems. The research is published online in Nature.
October 26, 2018 | Research News

Fast-flowing electrons may mimic astrophysical dynamos

A powerful engine roils deep beneath our feet, converting energy in the Earth’s core into magnetic fields that shield us from the solar wind. Similar engines drive the magnetic activity of the sun, other stars and even other planets—all of which create magnetic fields that reinforce themselves and feed back into the engines to keep them running.Much about these engines, which scientists refer to as dynamos, remains unknown. That’s partly because the math behind them is doubly difficult, combining the complex equations of fluid motion with the equations that govern how electric and magnetic fields bend, twist, interact and propagate. But it’s also because lab-bound dynamos, which attempt to mimic the astrophysical versions, are expensive, dangerous and do not yet reliably produce the signature self-sustaining magnetic fields of real dynamos.Now, Victor Galitski, a Fellow of the Joint Quantum Institute (JQI), in collaboration with two other scientists, has proposed a radical new approach to studying dynamos, one that could be simpler and safer. The proposal, which was published Oct. 25 in Physical Review Letters, suggests harnessing the electrons in a centimeter-sized chunk of solid matter to emulate the fluid flows in ordinary dynamos.
October 8, 2018 | PFC | Podcast

Black holes: The ultimate cosmic whisks

Chaos. Time travel. Quantum entanglement. Each may play a role in figuring out whether black holes are the universe’s ultimate information scramblers. In this episode of Relatively Certain, Chris sits down with Brian Swingle, a QuICS Fellow and assistant professor of physics at UMD, to learn about some of the latest theoretical research on black holes—and how experiments to test some of these theories are getting tantalizingly close.
September 17, 2018 | PFC | Research News

Modified superconductor synapse reveals exotic electron behavior

Electrons tend to avoid one another as they go about their business carrying current. But certain devices, cooled to near zero temperature, can coax these loner particles out of their shells. In extreme cases, electrons will interact in unusual ways, causing strange quantum entities to emerge. At the Joint Quantum Institute (JQI), Jimmy Williams’ group is working to develop new circuitry that could host such exotic states. These states have a feature that may make them useful in future quantum computers: They appear to be inherently protected from the destructive but unavoidable imperfections found in fabricated circuits. As described recently in Physical Review Letters, Williams’ team has reconfigured one workhorse superconductor circuit—a Josephson junction—to include a material suspected of hosting quantum states with boosted immunity.
September 10, 2018 | Research News

Pristine quantum light source created at the edge of silicon chip

The smallest amount of light you can have is one photon, so dim that it’s pretty much invisible to humans. While imperceptible, these tiny blips of energy are useful for carrying quantum information around. Ideally, every quantum courier would be the same, but there isn’t a straightforward way to produce a stream of identical photons. This is particularly challenging when individual photons come from fabricated chips. Now, researchers at the Joint Quantum Institute (JQI) have demonstrated a new approach that enables different devices to repeatedly emit nearly identical single photons. The team, led by JQI Fellow Mohammad Hafezi, made a silicon chip that guides light around the device’s edge, where it is inherently protected against disruptions. Previously, Hafezi and colleagues showed that this design can reduce the likelihood of optical signal degradation. In a paper published online on Sept. 10 in Nature, the team explains that the same physics which protects the light along the chip’s edge also ensures reliable photon production.
August 8, 2018 | People News | Research News

JQI scientists Monroe and Gorshkov are part of a new, $15 million NSF quantum computing project

NSF has announced a $15 million award to a collaboration of seven institutions, including the University of Maryland. The goal: Build the world’s first practical quantum computer."Quantum computers will change everything about the technology we use and how we use it, and we are still taking the initial steps toward realizing this goal," said NSF Director France Córdova. "Developing the first practical quantum computer would be a major milestone. By bringing together experts who have outlined a path to a practical quantum computer and supporting its development, NSF is working to take the quantum revolution from theory to reality."Dubbed the Software-Tailored Architecture for Quantum co-design (STAQ) project, the effort seeks to demonstrate a quantum advantage over traditional computers within five years using ion trap technology.The project is the result of a National Science Foundation Ideas Lab—a week-long, free-form exchange among researchers from a wide range of fields that aims to spawn creative, collaborative proposals to address a given research challenge. The result of each Ideas Lab is interdisciplinary research that is high-risk, high-reward, cutting-edge and unlikely to be funded through traditional grant mechanisms.JQI Fellow Christopher Monroe will lead the team developing the hardware. JQI Fellow Alexey Gorshkov will be involved in the theory side of the collaboration. Text for this news item was adapted from the Duke University and NSF press releases on the award.  
August 2, 2018 | PFC | Research News

Complexity test offers new perspective on small quantum computers

State-of-the-art quantum devices are not yet large enough to be called full-scale computers. The biggest comprise just a few dozen qubits—a meager count compared to the billions of bits in an ordinary computer’s memory. But steady progress means that these machines now routinely string together 10 or 20 qubits and may soon hold sway over 100 or more.In the meantime, researchers are busy dreaming up uses for small quantum computers and mapping out the landscape of problems they’ll be suited to solving. A paper by researchers from the Joint Quantum Institute (JQI) and the Joint Center for Quantum Information and Computer Science (QuICS), published recently in Physical Review Letters, argues that a novel non-quantum perspective may help sketch the boundaries of this landscape and potentially even reveal new physics in future experiments.

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