Cloud Computing

Researchers have succeeded in combining the power of quantum computing with the security of quantum cryptography and have shown that perfectly secure cloud computing can be achieved using the principles of quantum mechanics. They have performed an experimental demonstration of quantum computation in which the input, the data processing, and the output remain unknown to the quantum computer.

The international team of scientists will publish the results of the experiment, carried out at the Vienna Center for Quantum Science and Technology (VCQ) at the University of Vienna and the Institute for Quantum Optics and Quantum Information (IQOQI), in the forthcoming issue of Science.

Quantum computers are expected to play an important role in future information processing since they can outperform classical computers at many tasks. Considering the challenges inherent in building quantum devices, it is conceivable that future quantum computing capabilities will exist only in a few specialized facilities around the world -- much like today's supercomputers. Users would then interact with those specialized facilities in order to outsource their quantum computations. The scenario follows the current trend of cloud computing: central remote servers are used to store and process data -- everything is done in the "cloud." The obvious challenge is to make globalized computing safe and ensure that users' data stays private.

The latest research, to appear in Science, reveals that quantum computers can provide an answer to that challenge. "Quantum physics solves one of the key challenges in distributed computing. It can preserve data privacy when users interact with remote computing centers," says Stefanie Barz, lead author of the study. This newly established fundamental advantage of quantum computers enables the delegation of a quantum computation from a user who does not hold any quantum computational power to a quantum server, while guaranteeing that the user's data remain perfectly private. The quantum server performs calculations, but has no means to find out what it is doing -- a functionality not known to be achievable in the classical world.

The scientists in the Vienna research group have demonstrated the concept of "blind quantum computing" in an experiment: they performed the first known quantum computation during which the user's data stayed perfectly encrypted. The experimental demonstration uses photons, or "light particles" to encode the data. Photonic systems are well-suited to the task because quantum computation operations can be performed on them, and they can be transmitted over long distances.

The process works in the following manner. The user prepares qubits -- the fundamental units of quantum computers -- in a state known only to himself and sends these qubits to the quantum computer. The quantum computer entangles the qubits according to a standard scheme. The actual computation is measurement-based: the processing of quantum information is implemented by simple measurements on qubits. The user tailors measurement instructions to the particular state of each qubit and sends them to the quantum server. Finally, the results of the computation are sent back to the user who can interpret and utilize the results of the computation. Even if the quantum computer or an eavesdropper tries to read the qubits, they gain no useful information, without knowing the initial state; they are "blind."

The research at the Vienna Center for Quantum Science and Technology (VCQ) at the University of Vienna and at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences was undertaken in collaboration with the scientists who originally invented the protocol, based at the University of Edinburgh, the Institute for Quantum Computing (University of Waterloo), the Centre for Quantum Technologies (National University of Singapore), and University College Dublin
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Batteries

Looking toward improved batteries for charging electric cars and storing energy from renewable but intermittent solar and wind, scientists at Oak Ridge National Laboratory have developed the first high-performance, nanostructured solid electrolyte for more energy-dense lithium ion batteries.

Today's lithium-ion batteries rely on a liquid electrolyte, the material that conducts ions between the negatively charged anode and positive cathode. But liquid electrolytes often entail safety issues because of their flammability, especially as researchers try to pack more energy in a smaller battery volume. Building batteries with a solid electrolyte, as ORNL researchers have demonstrated, could overcome these safety concerns and size constraints.

"To make a safer, lightweight battery, we need the design at the beginning to have safety in mind," said ORNL's Chengdu Liang, who led the newly published study in the Journal of the American Chemical Society. "We started with a conventional material that is highly stable in a battery system -- in particular one that is compatible with a lithium metal anode."

The ability to use pure lithium metal as an anode could ultimately yield batteries five to 10 times more powerful than current versions, which employ carbon based anodes.

"Cycling highly reactive lithium metal in flammable organic electrolytes causes serious safety concerns," Liang said. "A solid electrolyte enables the lithium metal to cycle well, with highly enhanced safety."

The ORNL team developed its solid electrolyte by manipulating a material called lithium thiophosphate so that it could conduct ions 1,000 times faster than its natural bulk form. The researchers used a chemical process called nanostructuring, which alters the structure of the crystals that make up the material.

"Think about it in terms of a big crystal of quartz vs. very fine beach sand," said coauthor Adam Rondinone. "You can have the same total volume of material, but it's broken up into very small particles that are packed together. It's made of the same atoms in roughly the same proportions, but at the nanoscale the structure is different. And now this solid material conducts lithium ions at a much greater rate than the original large crystal."

The researchers are continuing to test lab scale battery cells, and a patent on the team's invention is pending.

"We use a room-temperature, solution-based reaction that we believe can be easily scaled up," Rondinone said. "It's an energy-efficient way to make large amounts of this material."

The study is published as "Anomalous High Ionic Conductivity of Nanoporous β-Li3PS4," and its ORNL coauthors are Zengcai Liu, Wujun Fu, Andrew Payzant, Xiang Yu, Zili Wu, Nancy Dudney, Jim Kiggans, Kunlun Hong, Adam Rondinone and Chengdu Liang. The work was sponsored by the Division of Materials Sciences and Engineering in DOE's Office of Science
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Geothermal

A new method for capturing significantly more heat from low-temperature geothermal resources holds promise for generating virtually pollution-free electrical energy. Scientists at the Department of Energy's Pacific Northwest National Laboratory will determine if their innovative approach can safely and economically extract and convert heat from vast untapped geothermal resources.

The goal is to enable power generation from low-temperature geothermal resources at an economical cost. In addition to being a clean energy source without any greenhouse gas emissions, geothermal is also a steady and dependable source of power.

"By the end of the calendar year, we plan to have a functioning bench-top prototype generating electricity," predicts PNNL Laboratory Fellow Pete McGrail. "If successful, enhanced geothermal systems like this could become an important energy source." A technical and economic analysis conducted by the Massachusetts Institute of Technology estimates that enhanced geothermal systems could provide 10 percent of the nation's overall electrical generating capacity by 2050.

PNNL's conversion system will take advantage of the rapid expansion and contraction capabilities of a new liquid developed by PNNL researchers called biphasic fluid. When exposed to heat brought to the surface from water circulating in moderately hot, underground rock, the thermal-cycling of the biphasic fluid will power a turbine to generate electricity.

To aid in efficiency, scientists have added nanostructured metal-organic heat carriers, or MOHCs, which boost the power generation capacity to near that of a conventional steam cycle. McGrail cited PNNL's nanotechnology and molecular engineering expertise as an important factor in the development, noting that the advancement was an outgrowth of research already underway at the lab.

"Some novel research on nanomaterials used to capture carbon dioxide from burning fossil fuels actually led us to this discovery," said McGrail. "Scientific breakthroughs can come from some very unintuitive connections."

PNNL is receiving $1.2 million as one of 21 DOE Energy Efficiency and Renewable Energy grants through the Geothermal Technologies Program.

Some of the research was conducted in EMSL, DOE's Environmental Molecular Sciences Laboratory on the PNNL campus
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Solar Power

"Many analysts project a higher cost for solar photovoltaic energy because they don't consider recent technological advancements and price reductions," says Joshua Pearce, Adjunct Professor, Department of Mechanical and Materials Engineering. "Older models for determining solar photovoltaic energy costs are too conservative."

Dr. Pearce believes solar photovoltaic systems are near the "tipping point" where they can produce energy for about the same price other traditional sources of energy.

Analysts look at many variables to determine the cost of solar photovoltaic systems for consumers, including installation and maintenance costs, finance charges, the system's life expectancy, and the amount of electricity it generates.

Dr. Pearce says some studies don't consider the 70 per cent reduction in the cost of solar panels since 2009 . Furthermore, he says research now shows the productivity of top-of-the-line solar panels only drops between 0.1 and 0.2 percent annually, which is much less than the one per cent used in many cost analyses.

Equipment costs are determined based on dollars per watt of electricity produced. One 2010 study estimated the this cost at $7.61, while a 2003 study set the amount at $4.16. According to Dr. Pearce, the real cost in 2011 is under $1 per watt for solar panels purchased in bulk on the global market, though he says system and installation costs vary widely.

Dr. Pearce has created a calculator program available for download online that can be used to determine the true costs of solar energy.

The Queen's study was co-authored by grad students Kadra Branker and Michael Pathak and published in the December edition of Renewable and Sustainable Energy Reviews
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