quantum computing

JQI Fellow Vladimir Manucharyan has received a 2019 Google Faculty Research Award. It is the second consecutive year that Manucharyan, who is also an Associate Professor of Physics at UMD, has earned the honor. This year’s award will continue to support research by Manucharyan and his team into quantum computing hardware based on superconducting circuits. They are pursuing the development of special quantum bits—called fluxonium qubits—for use in a new generation of computers.

JQI Fellow Mohammad Hafezi and JQI Graduate Researchers Alireza Seif and Hwanmun Kim have received an award from Google to support research identifying and developing problems that simple quantum computers might help solve. The work could bridge the divide between demonstrating quantum supremacy, as Google claimed to do in October, and building practical quantum computers that can run established algorithms.“It is an exciting time when industry and academia work together on quantum problems,” Hafezi says. “I am looking forward to collaborating with the Google AI team,” he adds, referring to Google’s artificial intelligence research arm.

Researchers at the University of Maryland (UMD) have trained a small hybrid quantum computer to reproduce the features in a particular set of images. The result, which was published Oct. 18, 2019 in the journal Science Advances, is among the first demonstrations of quantum hardware teaming up with conventional computing power—in this case to do generative modeling, a machine learning task in which a computer learns to mimic the structure of a given dataset and generate examples that capture the essential character of the data.

Scientists at the Joint Quantum Institute (JQI) have been steadily improving the performance of ion trap systems, a leading platform for future quantum computers. Now, a team of researchers led by JQI Fellows Norbert Linke and Christopher Monroe has performed a key experiment on five ion-based quantum bits, or qubits. They used laser pulses to simultaneously create quantum connections between different pairs of qubits—the first time these kinds of parallel operations have been executed in an ion trap. The new study, which is a critical step toward large-scale quantum computation, was published on July 24 in the journal Nature.    

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.

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.  

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.

Two independent teams of scientists, including one from the Joint Quantum Institute, have used more than 50 interacting atomic qubits to mimic magnetic quantum matter, blowing past the complexity of previous demonstrations. The results appear in this week’s issue of Nature.As the basis for its quantum simulation, the JQI team deploys up to 53 individual ytterbium ions—charged atoms trapped in place by gold-coated and razor-sharp electrodes. A complementary design by Harvard and MIT researchers uses 51 uncharged rubidium atoms confined by an array of laser beams. With so many qubits these quantum simulators are on the cusp of exploring physics that is unreachable by even the fastest modern supercomputers. And adding even more qubits is just a matter of lassoing more atoms into the mix.

Large-scale quantum computers, which are an active pursuit of many university labs and tech giants, remain years away. But that hasn’t stopped some scientists from thinking ahead, to a time when quantum computers might be linked together in a network or a single quantum computer might be split up across many interconnected nodes.A group of physicists at the University of Maryland, working with JQI Fellow Christopher Monroe, are pursuing the second goal, attempting to wire up isolated modules of trapped atomic ions with light. They imagine many modules, each with a hundred or so ions, linked together to form a quantum computer that is inherently scalable: If you want a bigger computer, simply add more modules to the mix.In a paper published recently in Physical Review Letters, Monroe and his collaborators reported on putting together many of the pieces needed to create such a module. It includes two different species of ions: an ytterbium ion for storing information and a barium ion for generating the light that communicates with other nodes.This dual-species approach isolates the storage and communication tasks of a network node. With a single species, manipulating the communication ion with a laser could easily corrupt the storage ion. In several experiments, the researchers demonstrated that they could successfully isolate the two ions from each other, transfer information between them and capture light generated by both ions. 

Deep within solids, individual electrons zip around on a nanoscale highway paved with atoms. For the most part, these electrons avoid one another, kept in separate lanes by their mutual repulsion. But vibrations in the atomic road can blur their lanes and sometimes allow the tiny particles to pair up. The result is smooth and lossless travel, and it’s one way to create superconductivity.But there are other, less common ways to achieve this effect. Scientists from the University of Maryland (UMD), the University of California, Irvine (UCI) and Fudan University have now shown that tiny magnetic tremors lead to superconductivity in a material made from metallic nano-layers. And, beyond that, the resulting electron pairs shatter a fundamental symmetry between past and future. Although the material is a known superconductor, these researchers provide a theoretical model and measurement, which, for the first time, unambiguously reveals the material’s exotic nature.