Quantum computer components 'coalesce' to 'converse'

ScienceDaily (Oct. 26, 2011) — If quantum computers are ever to be realized, they likely will be made of different types of parts that will need to share information with one another, just like the memory and logic circuits in today's computers do. However, prospects for achieving this kind of communication seemed distant -- until now. A team of physicists working at the National Institute of Standards and Technology (NIST) has shown for the first time how these parts might communicate effectively.

The goal to develop quantum computers -- a long-awaited type of computer that could solve otherwise intractable problems, such as breaking complex encryption codes -- has inspired scientists the world over to invent new devices that could become the brains and memory of these machines. Many of these tiny devices use particles of light, or photons, to carry the bits of information that a quantum computer will use.

But while each of these pieces of hardware can do some jobs well, none are likely to accomplish all of the functions necessary to build a quantum computer. This implies that several different types of quantum devices will need to work together for the computer or network to function. The trouble is that these tiny devices frequently create photons of such different character that they cannot transfer the quantum bits of information between one another. Transmuting two vastly different photons into two similar ones would be a first step toward permitting quantum information components to communicate with one another over large distances, but until now this goal has remained elusive.

However, the team has demonstrated that it is possible to take photons from two disparate sources and render these particles partially indistinguishable. That photons can be made to "coalesce" and become indistinguishable without losing their essential quantum properties suggests in principle that they can connect various types of hardware devices into a single quantum information network. The team's achievement also demonstrates for the first time that a "hybrid" quantum computer might be assembled from different hardware types.

The team connected single photons from a "quantum dot," which could be useful in logic circuits, with a second single-photon source that uses "parametric down conversion," which might be used to connect different parts of the computer. These two sources typically produce photons that differ so dramatically in spectrum that they would be unusable in a quantum network. But with a deft choice of filters and other devices that alter the photons' spectral shapes and other properties, the team was able to make the photons virtually identical.

"We manipulate the photons to be as indistinguishable as possible in terms of spectra, location and polarization -- the details you need to describe a photon. We attribute the remaining distinguishability to properties of the quantum dot," says Glenn Solomon, of NIST's Quantum Measurement Division. "No conceivable measurement can tell indistinguishable photons apart. The results prove in principle that a hybrid quantum network is possible and can be scaled up for use in a quantum network."

The research team includes scientists from the NIST/University of Maryland Joint Quantum Institute (JQI) and Georgetown University. The NSF Physics Frontier Center at JQI provided partial funding.

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The above story is reprinted from materials provided by National Institute of Standards and Technology (NIST).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Sergey Polyakov, Andreas Muller, Edward Flagg, Alex Ling, Natalia Borjemscaia, Edward Van Keuren, Alan Migdall, Glenn Solomon. Coalescence of Single Photons Emitted by Disparate Single-Photon Sources: The Example of InAs Quantum Dots and Parametric Down-Conversion Sources. Physical Review Letters, 2011; 107 (15) DOI: 10.1103/PhysRevLett.107.157402

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Electromobility: New components going for a test run

ScienceDaily (Oct. 17, 2011) — The future belongs to electrical cars -- that's what most experts think. Unfortunately, there are still a lot of problems that have not been solved. This is the reason why researchers at 33 Fraunhofer institutes put their heads together in the Fraunhofer System Research for Electromobility project to move electromobility one big step ahead.

This two-year project was completed on July 30, 2011, and the demonstrator vehicles they came up with were showcased at the final event in Papenburg, Germany, on September 2, 2011, on the ATP test track.

In the future, it will be whisper-quiet on road because in the long run electric cars will replace the internal combustion engine. But there are still some unanswered questions. For instance, how do you store the electricity in cars? Or what power networks do you need? And anyway, how do you pay for charging your battery? Two years ago, researchers from 33 Fraunhofer institutes joined forces to answer these and many other questions while coordinating the various components of electrical cars. The idea behind this partnership is supporting the German car and supply industry to make sure they stay on top in electromobility for a long time to come. This is why this project was funded by the German Federal Ministry of Education and Research with 34.5 million euros from its Economic Policy Program II.

Professor Ulrich Buller is the Senior Vice President for Research at Fraunhofer Gesellshaft. He describes the idea behind system research: "We take care of overarching aspects starting with generating the energy and going all the way down to business models." Professor Holger Hanselka is the director of the Fraunhofer Institute for Structural Durability and System Reliability LBF and the project coordinator. He goes into detail: "We have defined a total of five concentrations: issues of decentralized power generation and power transport to vehicles, energy storage, vehicle engineering and system integration. We're talking about new value-added chains and getting people to accept the idea of electromobility. We added the concentration of 'function, reliability, testing and launch' in 2011."

After the project was over, the institutes involved unveiled their findings on the ATP test track in Papenburg, Germany, on September 2; researchers invited visitors for a test ride in the experimental vehicles. This is where the first and second generation of Fraunhofer's Frecc0 developmental vehicles are ready for testing. Both of these electrical cars are based upon Artega GT, a two-seater sports car. Franz-Josef Wöstmann, division director at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen, Germany, says: "We installed commercially available components into the Frecc0 1.0 and concentrated on streamlining the way these components interact." This Fraunhofer Institute took on project management for building the Frecc0 demonstrator vehicle.

Frecc0 2.0 contains components recently developed by these scientists. A case in point are wheel hub motors that the researchers from IFAM conceived in teamwork with their colleagues at the Fraunhofer Institute for Integrated Systems and Device Technology IISB, the Fraunhofer Institute for Mechanics of Materials IWM and the Fraunhofer Institute for Structural Durability and System Reliability LBF. Franz-Josef Wöstmann stresses, "We engineered the motor from the onset for the European market and we selected a diameter to make sure it has room in a 15-inch wheel rim. In turn, the engine is adapted to the available construction space. This is why we had to come up with completely new components with maximum power density -- starting with the power electronics through setting up the cooling right down to the design."

Totally new vehicle designs are possible since the researchers moved the entire drive train -- the entire engine including the center tunnel, cardan shaft and transmission -- out of the car and into the wheel hubs or even eliminated them altogether. For instance, the passenger compartment on a vehicle that is about the same size as a VW Passat would be as big as an S-Class Mercedes. Another advantage is the fact that every wheel gets the performance it needs. This means greater safety for each passenger because each individual wheel cannot only be separately braked, but also accelerated. That gives the wheel hub motor torque vectoring, an advancement over today's ESP. Franz-Josef Wöstmann adds that "all components in the wheel hub motor are designed for series production."

Another innovation is the cast coil. Now, Fraunhofer researchers can cast coils with a new technique instead of winding them as previously. This has the benefit that the installation space in the drive motor is used more efficiently. In contrast to the lot fill factor of approximately 55 percent normal today, experts achieve lot fill factors in excess of 90 percent. This permits higher power density and greater efficiency with an equally large coil installation space. Much smaller coils can be used due to the higher lot fill factors, or aluminum can be used with the same dimensions if engine output is supposed to stay the same. Felix Horch from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials explains: "Thanks to this new production technology, we can substantially reduce the installation space, weight and price for coils."

Incidentally, Fraunhofer scientists were not the only ones to use the Frecc0 as a test platform. In the future, automobile manufacturers and suppliers will be able to use Frecc0 together with the Fraunhofer Institute for Manufacturing Technology and Advanced Materials for testing or advancing new components.

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Note: ScienceDaily reserves the right to edit materials for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Electromobility: New components going for a test run

ScienceDaily (Oct. 17, 2011) — The future belongs to electrical cars -- that's what most experts think. Unfortunately, there are still a lot of problems that have not been solved. This is the reason why researchers at 33 Fraunhofer institutes put their heads together in the Fraunhofer System Research for Electromobility project to move electromobility one big step ahead.

This two-year project was completed on July 30, 2011, and the demonstrator vehicles they came up with were showcased at the final event in Papenburg, Germany, on September 2, 2011, on the ATP test track.

In the future, it will be whisper-quiet on road because in the long run electric cars will replace the internal combustion engine. But there are still some unanswered questions. For instance, how do you store the electricity in cars? Or what power networks do you need? And anyway, how do you pay for charging your battery? Two years ago, researchers from 33 Fraunhofer institutes joined forces to answer these and many other questions while coordinating the various components of electrical cars. The idea behind this partnership is supporting the German car and supply industry to make sure they stay on top in electromobility for a long time to come. This is why this project was funded by the German Federal Ministry of Education and Research with 34.5 million euros from its Economic Policy Program II.

Professor Ulrich Buller is the Senior Vice President for Research at Fraunhofer Gesellshaft. He describes the idea behind system research: "We take care of overarching aspects starting with generating the energy and going all the way down to business models." Professor Holger Hanselka is the director of the Fraunhofer Institute for Structural Durability and System Reliability LBF and the project coordinator. He goes into detail: "We have defined a total of five concentrations: issues of decentralized power generation and power transport to vehicles, energy storage, vehicle engineering and system integration. We're talking about new value-added chains and getting people to accept the idea of electromobility. We added the concentration of 'function, reliability, testing and launch' in 2011."

After the project was over, the institutes involved unveiled their findings on the ATP test track in Papenburg, Germany, on September 2; researchers invited visitors for a test ride in the experimental vehicles. This is where the first and second generation of Fraunhofer's Frecc0 developmental vehicles are ready for testing. Both of these electrical cars are based upon Artega GT, a two-seater sports car. Franz-Josef Wöstmann, division director at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen, Germany, says: "We installed commercially available components into the Frecc0 1.0 and concentrated on streamlining the way these components interact." This Fraunhofer Institute took on project management for building the Frecc0 demonstrator vehicle.

Frecc0 2.0 contains components recently developed by these scientists. A case in point are wheel hub motors that the researchers from IFAM conceived in teamwork with their colleagues at the Fraunhofer Institute for Integrated Systems and Device Technology IISB, the Fraunhofer Institute for Mechanics of Materials IWM and the Fraunhofer Institute for Structural Durability and System Reliability LBF. Franz-Josef Wöstmann stresses, "We engineered the motor from the onset for the European market and we selected a diameter to make sure it has room in a 15-inch wheel rim. In turn, the engine is adapted to the available construction space. This is why we had to come up with completely new components with maximum power density -- starting with the power electronics through setting up the cooling right down to the design."

Totally new vehicle designs are possible since the researchers moved the entire drive train -- the entire engine including the center tunnel, cardan shaft and transmission -- out of the car and into the wheel hubs or even eliminated them altogether. For instance, the passenger compartment on a vehicle that is about the same size as a VW Passat would be as big as an S-Class Mercedes. Another advantage is the fact that every wheel gets the performance it needs. This means greater safety for each passenger because each individual wheel cannot only be separately braked, but also accelerated. That gives the wheel hub motor torque vectoring, an advancement over today's ESP. Franz-Josef Wöstmann adds that "all components in the wheel hub motor are designed for series production."

Another innovation is the cast coil. Now, Fraunhofer researchers can cast coils with a new technique instead of winding them as previously. This has the benefit that the installation space in the drive motor is used more efficiently. In contrast to the lot fill factor of approximately 55 percent normal today, experts achieve lot fill factors in excess of 90 percent. This permits higher power density and greater efficiency with an equally large coil installation space. Much smaller coils can be used due to the higher lot fill factors, or aluminum can be used with the same dimensions if engine output is supposed to stay the same. Felix Horch from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials explains: "Thanks to this new production technology, we can substantially reduce the installation space, weight and price for coils."

Incidentally, Fraunhofer scientists were not the only ones to use the Frecc0 as a test platform. In the future, automobile manufacturers and suppliers will be able to use Frecc0 together with the Fraunhofer Institute for Manufacturing Technology and Advanced Materials for testing or advancing new components.

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Story Source:

The above story is reprinted from materials provided by Fraunhofer-Gesellschaft.

Note: ScienceDaily reserves the right to edit materials for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

'Biological circuit' components developed; New microscope technique for measuring them

ScienceDaily (June 9, 2011) — Electrical engineers have long been toying with the idea of designing biological molecules that can be directly integrated into electronic circuits. University of Pennsylvania researchers have developed a way to form these structures so they can operate in open-air environments, and, more important, have developed a new microscope technique that can measure the electrical properties of these and similar devices.

The research was conducted by Dawn Bonnell, Trustee Chair Professor and director of the Nano/Bio Interface Center, graduate students Kendra Kathan-Galipeau and Maxim Nikiforov and postdoctoral fellow Sanjini Nanayakkara, all of the Department of Materials Science and Engineering in Penn's School of Engineering and Applied Science. They collaborated with assistant professor Bohdana Discher of the Department of Biophysics and Biochemistry at Penn's Perelman School of Medicine and Paul A. O'Brien, a graduate student in Penn's Biotechnology Masters Program.

Their work was published in the journal ACS Nano.

The development involves artificial proteins, bundles of peptide helices with a photoactive molecule inside. These proteins are arranged on electrodes, which are common feature of circuits that transmit electrical charges between metallic and non-metallic elements. When light is shined on the proteins, they convert photons into electrons and pass them to the electrode.

"It's a similar mechanism to what happens when plants absorb light, except in that case the electron is used for some chemistry that creates energy for the plant," Bonnell said. "In this case, we want to use the electron in electrical circuits."

Similar peptide assemblies had been studied in solution before by several groups and had been tested to show that they indeed react to light. But there was no way to quantify their ambient electrical properties, particularly capacitance, the amount of electrical charge the assembly holds.

"It's necessary to understand these kinds of properties in the molecules in order to make devices out of them. We've been studying silicon for 40 years, so we know what happens to electrons there," Bonnell said. "We didn't know what happens to electrons on dry electrodes with these proteins; we didn't even know if they would remain photoactive when attached to an electrode."

Designing circuits and devices with silicon is inherently easier than with proteins. The electrical properties of a large chunk of a single element can be measured and then scaled down, but complex molecules like these proteins cannot be scaled up. Diagnostic systems that could measure their properties with nanometer sensitivity simply did not exist.

The researchers therefore needed to invent both a new way of a measuring these properties and a controlled way of making the photovoltaic proteins that would resemble how they might eventually be incorporated into devices in open-air, everyday environments, rather than swimming in a chemical solution.

To solve the first problem, the team developed a new kind of atomic force microscope technique, known as torsional resonance nanoimpedance microscopy. Atomic force microscopes operate by bringing an extremely narrow silicon tip very close to a surface and measuring how the tip reacts, providing a spatial sensitivity of a few nanometers down to individual atoms.

"What we've done in our version is to use a metallic tip and put an oscillating electric field on it. By seeing how electrons react to the field, we're able to measure more complex interactions and more complex properties, such as capacitance," Bonnell said.

Bohdana Discher's group designed the self-assembling proteins much as they had done before but took the additional step of stamping them onto sheets of graphite electrodes. This manufacturing principle and the ability to measure the resulting devices could have a variety of applications.

"Photovoltaics -- solar cells -- are perhaps the easiest to imagine, but where this work is going in the shorter term is biochemical sensors," Bonnell said.

Instead of reacting to photons, proteins could be designed to produce a charge when in the presence of a certain toxins, either changing color or acting as a circuit element in a human-scale gadget.

This research was supported by the Nano/Bio Interface Center and the National Science Foundation.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Pennsylvania.

Journal Reference:

Kendra Kathan-Galipeau, Sanjini Nanayakkara, Paul A. O’Brian, Maxim Nikiforov, Bohdana M. Discher, Dawn A. Bonnell. Direct Probe of Molecular Polarization inDe NovoProtein–Electrode Interfaces. ACS Nano, 2011; 110603081000090 DOI: 10.1021/nn200887n

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

'Biological circuit' components developed; New microscope technique for measuring them

ScienceDaily (June 9, 2011) — Electrical engineers have long been toying with the idea of designing biological molecules that can be directly integrated into electronic circuits. University of Pennsylvania researchers have developed a way to form these structures so they can operate in open-air environments, and, more important, have developed a new microscope technique that can measure the electrical properties of these and similar devices.

The research was conducted by Dawn Bonnell, Trustee Chair Professor and director of the Nano/Bio Interface Center, graduate students Kendra Kathan-Galipeau and Maxim Nikiforov and postdoctoral fellow Sanjini Nanayakkara, all of the Department of Materials Science and Engineering in Penn's School of Engineering and Applied Science. They collaborated with assistant professor Bohdana Discher of the Department of Biophysics and Biochemistry at Penn's Perelman School of Medicine and Paul A. O'Brien, a graduate student in Penn's Biotechnology Masters Program.

Their work was published in the journal ACS Nano.

The development involves artificial proteins, bundles of peptide helices with a photoactive molecule inside. These proteins are arranged on electrodes, which are common feature of circuits that transmit electrical charges between metallic and non-metallic elements. When light is shined on the proteins, they convert photons into electrons and pass them to the electrode.

"It's a similar mechanism to what happens when plants absorb light, except in that case the electron is used for some chemistry that creates energy for the plant," Bonnell said. "In this case, we want to use the electron in electrical circuits."

Similar peptide assemblies had been studied in solution before by several groups and had been tested to show that they indeed react to light. But there was no way to quantify their ambient electrical properties, particularly capacitance, the amount of electrical charge the assembly holds.

"It's necessary to understand these kinds of properties in the molecules in order to make devices out of them. We've been studying silicon for 40 years, so we know what happens to electrons there," Bonnell said. "We didn't know what happens to electrons on dry electrodes with these proteins; we didn't even know if they would remain photoactive when attached to an electrode."

Designing circuits and devices with silicon is inherently easier than with proteins. The electrical properties of a large chunk of a single element can be measured and then scaled down, but complex molecules like these proteins cannot be scaled up. Diagnostic systems that could measure their properties with nanometer sensitivity simply did not exist.

The researchers therefore needed to invent both a new way of a measuring these properties and a controlled way of making the photovoltaic proteins that would resemble how they might eventually be incorporated into devices in open-air, everyday environments, rather than swimming in a chemical solution.

To solve the first problem, the team developed a new kind of atomic force microscope technique, known as torsional resonance nanoimpedance microscopy. Atomic force microscopes operate by bringing an extremely narrow silicon tip very close to a surface and measuring how the tip reacts, providing a spatial sensitivity of a few nanometers down to individual atoms.

"What we've done in our version is to use a metallic tip and put an oscillating electric field on it. By seeing how electrons react to the field, we're able to measure more complex interactions and more complex properties, such as capacitance," Bonnell said.

Bohdana Discher's group designed the self-assembling proteins much as they had done before but took the additional step of stamping them onto sheets of graphite electrodes. This manufacturing principle and the ability to measure the resulting devices could have a variety of applications.

"Photovoltaics -- solar cells -- are perhaps the easiest to imagine, but where this work is going in the shorter term is biochemical sensors," Bonnell said.

Instead of reacting to photons, proteins could be designed to produce a charge when in the presence of a certain toxins, either changing color or acting as a circuit element in a human-scale gadget.

This research was supported by the Nano/Bio Interface Center and the National Science Foundation.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Pennsylvania.

Journal Reference:

Kendra Kathan-Galipeau, Sanjini Nanayakkara, Paul A. O’Brian, Maxim Nikiforov, Bohdana M. Discher, Dawn A. Bonnell. Direct Probe of Molecular Polarization inDe NovoProtein–Electrode Interfaces. ACS Nano, 2011; 110603081000090 DOI: 10.1021/nn200887n

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here