The White House is honoring Robert Fischell, a scientist and inventor whose 2005 donation established the University of Maryland's Fischell Department of Bioengineering, with the National Medal of Technology and Innovation for his work developing medical devices. Read More

A team of researchers led by Duke University and the University of Maryland has been tapped by the nation’s “Q Branch” to take quantum computing efforts to the next level using one of the field’s leading technologies—ion traps. Read More

A team of researchers led by Duke University and the University of Maryland has been tapped by the nation’s “Q Branch” to take quantum computing efforts to the next level using one of the field’s leading technologies—ion traps.

The Intelligence Advanced Research Projects Activity (IARPA) invests in high-risk, high-payoff research programs to tackle some of the most difficult challenges in the intelligence community. One of these challenges is dealing with encryption. Codes considered unbreakable by today’s best supercomputers could be handled in a matter of hours by quantum computers.

The basic building blocks of a quantum device are qubits. These are the quantum mechanical analogue of a traditional logical bit, which can be in a “1” or a “0” state. Quantum physics allows for qubits to take on multiple configurations simultaneously (e.g. an equally-weighted superposition of 0 and 1), which is forbidden in conventional computing. When scientists in the 1990s proved that this strange property could be harnessed for solving certain tasks, such as decryption, the quantum information revolution began.

While researchers have proven that robust qubits can be built, scaling them into large networks while detecting and correcting errors remains a challenge.

IARPA awarded the Duke/Maryland/Georgia Tech partnership a five-year, $31.9 million grant through its program dubbed LogiQ. Their goal is to bring together a large number of atomic qubits to realize modular “super-qubits” that can be scaled up while correcting for errors. This major multi-year award is led by Jungsang Kim (Duke University), Christopher Monroe (University of Maryland and the Joint Quantum Institute) and Ken Brown (Georgia Tech).

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University of Maryland physicists have developed a new cloaking material that can become transparent to microwave radiation with the flip of a switch. Because many wireless communication devices rely on microwaves, the new material could be used to design more efficient communications networks. Additionally, the material has unique properties that could help bridge the gap between modern digital computers and next-generation “quantum” computers.

The new material can be selectively tuned to respond to a wide range of microwave wavelengths, making it more versatile than many previous attempts at cloaking technology. The achievement is described in a paper published on December 18, 2015 in the journal Physical Review X. The UMD researchers teamed with HYPRES, an advanced electronics company based in Elmsford, NY, on the project.

“Prior to this work, other cloaking materials were only effective at a single wavelength, which is not realistically useful,” said Daimeng Zhang, lead author of the study and a graduate student in electrical and computer engineering at UMD. “Our material is transparent across a broad range of microwave wavelengths. Also, we can turn the microwave transparency on and off. This hasn’t been explored before.”

This schematic illustrates a new self-cloaking metamaterial developed by University of Maryland physicists in collaboration with HYPRES, Inc. An array of miniature devices (circular structures) called rf-SQUIDs can become transparent to microwave radiation with the flip of a switch. At left, the material is in transparent mode and allows microwaves to travel freely. At right, the material is in opaque mode and prevents microwaves from traversing the barrier. Image credit: Sean Kelley/JQI (Click image to download hi-res version.)

This schematic illustrates a new self-cloaking metamaterial developed by University of Maryland physicists in collaboration with HYPRES, Inc. An array of miniature devices (circular structures) called rf-SQUIDs can become transparent to microwave radiation with the flip of a switch. At left, the material is in transparent mode and allows microwaves to travel freely. At right, the material is in opaque mode and prevents microwaves from traversing the barrier. Image credit: Sean Kelley/JQI (Click image to download hi-res version.)

The cloaking material developed at UMD cannot make other objects (or people) disappear. Instead, by selectively becoming transparent to microwave radiation, it can either shield or expose a target to incoming microwaves. For this reason, the researchers use the terms “auto-cloaking” or “self-cloaking” to describe the material.

“In that sense, our material could be said to work in reverse. When the transparency is turned on, any object behind it is visible to microwave detection,” said Steven Anlage, senior author of the study and a professor of physics at UMD. “But when the transparency is turned off, the material becomes a barrier and conceals anything behind it. It’s a good hider.”

The cloaking material is considered a metamaterial, or a “smart” material engineered to have properties not found in nature. Metamaterials are made of an array of “meta-atoms,” which are not atoms in the true chemical sense, but rather the smallest component parts of a metamaterial. The meta-atoms used in the UMD cloaking material are tiny devices—not much wider than a human hair—called Radio Frequency Superconducting QUantum Interference Devices (rf-SQUIDs). Each rf-SQUID exhibits the same properties as the metamaterial, meaning that the technology theoretically can be scaled up to any size.

“Previous attempts at cloaking technology could only respond to one wavelength,” said Melissa Trepanier, a co-author of the study and a graduate student in physics at UMD. “Perhaps more importantly, the wavelength could not be changed after the material was created. This meant that engineers needed to decide on—and commit to—a target wavelength prior to the design and construction phase.”

The UMD researchers solved this problem by designing the rf-SQUIDs with properties that can be tuned by varying the magnetic field applied to the material and/or the temperature of the material.

Zhang, Trepanier and Anlage co-authored the study with Oleg Mukhanov, chief technology officer of HYPRES. The research was supported by the National Science Foundation’s Grant Opportunities for Academic Liaison with Industry (GOALI) program. The GOALI program is designed to fund high-risk/high-reward research projects and enhance collaborations between academic scientists and industry.

Beyond its use for cloaking, the rf-SQUID-based metamaterial might help solve other technological challenges, including the implementation of quantum computers.

“HYPRES is very interested in the interface between quantum computing and classical digital computing, so we are looking for new technology capable of connecting the two,” Mukhanov said. “This new metamaterial has properties that are sensitive to both quantum processes and superconducting digital logic, so it would most likely be cross-compatible.”

“We’re working on the edges of what anyone has done before,” Anlage added. “It’s wild stuff, but there is a lot of potential to help develop cool new technology.”

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This work was supported by the National Science Foundation through the Grant Opportunities for Academic Liaison with Industry (GOALI) program (Award No. ECCS-1158644). The content of this article does not necessarily reflect the views of this organization.

The research paper, “Tunable Broadband Transparency of Macroscopic Quantum Superconducting Metamaterials,” Daimeng Zhang, Melissa Trepanier, Oleg Mukhanov and Steven Anlage, was published on December 18, 2015 in the journal Physical Review X.

A new set of calibration techniques has once again dramatically improved the sensitivity of the Large Underground Xenon (LUX) dark matter experiment, which operates nearly a mile underground at the Sanford Underground Research Facility (SURF) in the Black Hills of South Dakota. Read More