'Quantum Data Buffering' Scheme Demonstrated; Potentially Useful For Quantum Computers

Closeup of two "quantum images" created with the help of a "pump" laser beam. The two images are "entangled," so that if there is a change in the intensity in one region ("pixel") of the image, there would be an identical change in the intensity in the corresponding pixel in the second image. In this experiment, one of the images is delayed on its arrival to a detector, so that the correlations between the two images can be out of sync by up to 27 nanoseconds, something that is potentially useful for managing data to a future "quantum computer."

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Pushing the envelope of Albert Einstein's "spooky action at a distance," known as entanglement, researchers at the Joint Quantum Institute (JQI) of the Commerce Department's National Institute of Standards and Technology (NIST) and the University of Maryland have demonstrated a "quantum buffer," a technique that could be used to control the data flow inside a quantum computer. Quantum computers could potentially speed up or expand present capabilities in decrypting data, searching large databases, and other tasks.
The new research is published in the Feb. 12 issue of the journal Nature.
"If you want to set up some sort of communications system or a quantum information-processing system, you need to control the arrival time of one data stream relative to other data streams coming in," says JQI's Alberto Marino, lead author of the paper. "We can accomplish the delay in a compact setup, and we can rapidly change the delay if we want, something that would not be possible with usual laboratory apparatus such as beamsplitters and mirrors," he says.

This new work follows up on the researchers' landmark creation in 2008 of pairs of multi-pixel quantum images. A pair of quantum images is "entangled," which means that their properties are linked in such a way that they exist as a unit rather than individually. In the JQI work, each quantum image is carried by a light beam and consists of up to 100 "pixels." A pixel in one quantum image displays random and unpredictable changes say, in intensity, yet the corresponding pixel in the other image exhibits identical intensity fluctuations at the same time, and these fluctuations are independent from fluctuations in other pixels. This entanglement can persist even if the two images are physically disconnected from one another.
By using a gas cell to slow down one of the light beams to 500 times slower than the speed of light, the group has demonstrated that they could delay the arrival time of one of the entangled images at a detector by up to 27 nanoseconds. The correlations between the two entangled images still occur—but they are out of sync. A flicker in the first image would have a corresponding flicker in the slowed-down image up to 27 nanoseconds later.
While such "delayed entanglement" has been demonstrated before, it has never been accomplished in information-rich quantum images. Up to now, the "spooky action at a distance" has usually been delayed in single-photon systems.
"What gives our system the potential to store lots of data is the combination of having multiple-pixel images and the possibility of each pixel containing 'continuous' values for properties such as the intensity," says co-author Raphael Pooser.
To generate the entanglement, the researchers use a technique known as four-wave mixing, in which incoming light waves are mixed with a "pump" laser beam in a rubidium gas cell to generate a pair of entangled light beams. In their experiment, the researchers then send one of the entangled light beams through a second cell of rubidium gas where a similar four-wave mixing process is used to slow down the beam. The beam is slowed down as a result of the light being absorbed and re-emitted repeatedly in the gas. The amount of delay caused by the gas cell can be controlled by changing the temperature of the cell (by modifying the density of the gas atoms) and also by changing the intensity of the pump beam for the second cell.
This demonstration shows that this type of quantum buffer could be particularly useful for quantum computers, both in its information capacity and its potential to deliver data at precisely defined times.
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Adapted from materials provided by National Institute of Standards and Technology.

Compact Biosensor For Wide-ranging Applications Under Development

This portable magnetoresistive biosensor system utilizes an IC chip with an embedded giant magnetoresistance sensor array called the Bead ARray Counter (BARC). BARC detects paramagnetic microparticles that are used to label protein or DNA molecules of interest in a sandwich-based assay. The BARC chip is housed in an assay cartridge which contains an integrated fluid cell, microfludics bus and a PCMCIA connector to quickly interface with the compact Bead Array Sensor System (cBASS). cBASS includes a low power electromagnet, an automated fluidic system, and supporting electronics, all of which is controlled by a computer through a USB interface.

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Scientists at the Naval Research Laboratory (NRL) are partnering with industry to develop a sensor system for biomolecules that could make a significant contribution to a variety of fields such as healthcare, veterinary diagnostics, food safety, environmental testing, and national security.
NRL has developed a highly sensitive, portable biosensor system called the compact Bead Array Sensor System (cBASS®). This innovative instrument utilizes a special integrated sensor chip, called the Bead ARray Counter (BARC®), which contains an embedded array of giant magnetoresistive sensors. With 64, 200 µm diameter sensors on the chip, BARC® has the potential to detect 64 different target analytes.
Through the efforts of Dr. Lloyd Whitman, former head of the Surface Nanoscience and Sensor Technology Section at NRL, the NRL-developed technology has been licensed to Seahawk Biosystems Corporation in Rockville, Maryland, for further development in veterinary diagnostic, clinical diagnostic, and environmental applications.

Researchers at NRL began working on the magnetoelectronic biosensor concept more than a decade ago, under the leadership of Dr. Richard Colton and former NRL researcher Dr. David Baselt. Dr. Baselt used a quantum-mechanical effect called giant magnetoresistance (GMR). In simplistic terms, GMR materials are magnetic field-dependent resistors, i.e. their resistance changes when subjected to an externally applied magnetic field. GMR devices are typically constructed of alternating magnetic and non-magnetic metal thin-film multilayers that are only nanometers in thickness.
Dr. Baselt looked specifically at a type of GMR called multilayer GMR in which the resistance of two thin antiferromagnetically exchange-coupled layers, separated by a thin non-magnetic conducting layer, can be altered by changing the moments of the ferromagnetic layers from anti-parallel to parallel. This change decreases the spin-dependent interfacial scattering of charge carriers resulting in a decrease in the resistance of the GMR material.
Dr. Baselt realized this very sensitive phenomenon could have potential in the development of sensors for biological materials which are naturally biochemically specific, but are not usually magnetic. By attaching tiny paramagnetic particles to biomolecules, such as proteins or single-stranded DNA, scientists could then perform standard sandwich-type immuno or nucleic acid hybridization assays over the GMR sensors.
The GMR sensors, each covered with complementary protein or single-stranded DNA (the "probe"), could then detect the magnetically labeled biomolecules (the "target") the assays were designed to identify.
A decade in the making, the instrumentation that reads the BARC® chip is called the "compact Bead Array Sensor System" (cBASS®). NRL's current engineering team is led by Dr. Cy Tamanaha, working with Dr. Jack Rife, Mr. Matthew Kniller, and Mr. Michael Malito. The engineering team has worked to make many improvements to cBASS®, including:
• a new quick assembly assay cartridge with an integrated microfluidic cell, PCMCIA interface and kinematic microfluidics bus;
• an onboard fully automated fluidic valve and pumping system;
• a new electromagnet design with lower power requirements;
• a faster data exchange via USB with the controlling computer; and
• a rechargeable battery unit for enhanced portability (they have shrunk cBASS® down to approximately the size of a shoebox).

Ultimately, the success of the NRL's magnetoelectronic biosensor depends on the performance of the microbead label assays whose continued development is currently spearheaded by Dr. Shawn Mulvaney with the assistance of Ms. Kristina Myers. Over the past several years, NRL has made significant strides in surface biofunctionalization and assay development. With these advances, they have achieved high sensitivity and speed; low, non-specific binding with femtomolar DNA and attomolar protein detection, typically in less than 10 minutes.
One important characteristic of the NRL-developed assays is that the size of the microbead labels allows for either magnetoelectronic detection with GMR sensors, or optical enumeration with image processing software via a standard low-power microscope. The detection sensitivity under each method is nearly identical. However, there are differences in the two methods related to the size of the detection system and the cost of the consumables used.
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Adapted from materials provided by Naval Research Laboratory.

Robot Playmates Monitor Emotional State Of Children With Autism

Wired participant demonstrates plays the nerf basketball game.

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The day that robot playmates help children with autism learn the social skills that they naturally lack has come a step closer with the development of a system that allows a robot to monitor a child's emotional state.
"There is a lot of research going on around the world today trying to use robots to treat children with autism spectrum disorders (ASD). It has shown that the children are attracted to robots, raising the promise that appropriately designed robots could play an important role in their treatment," says Nilanjan Sarkar, associate professor of mechanical engineering at Vanderbilt University. "However, the efforts so far have been quite limited because they haven't had a way to monitor the emotional state of the children, which would allow the robot to respond automatically to their reactions."

If these limitations can be overcome, the use of robots to treat children with ASD could have a significant social and financial impact. One baby in every 150 born today in the United States is diagnosed with ASD, making it more common than pediatric cancer, diabetes and AIDS combined. Currently, treatment of these children involves a combination of behavioral, educational, physical, occupational and speech therapies, sometimes accompanied by medication for co-occurring conditions such as anxiety, irritability, bi-polar and other disorders. The average cost of caring for one person with autism for life is $3.2 million. In total, autism currently costs the U.S. more than $90 billion per year, and that cost is projected to double by 2017 due to the growing population of those affected.
Over the last five years, Sarkar has developed a method that uses physiological measurements, including heart rate, galvanic skin response, temperature and muscle response, to monitor the emotional state of individuals. His original motivation was to improve human-robot interactions. When his nephew was diagnosed with autism, however, Sarkar got the idea of applying the technique to aid children with ASD. So he sought out one of the leading authorities on the subject, Wendy Stone, professor of pediatrics and investigator at Vanderbilt's Kennedy Center, and they formed a partnership to develop this new approach.
"I'm always interested in creative ways to study and treat autism, so, when Nilanjan approached me, I was willing to listen," says Stone. "He had clearly done his homework and his proposal sounded like a great idea."
This fall, Sarkar and Stone published two papers – one in the IEEE Transactions on Robotics and one in the International Journal of Human-Computer Studies – that describe the results of their first set of experiments, which were conducted with six children ranging in age from 13 to 16 years who had been diagnosed with ASD. A battery of physiological sensors were attached to the participants and they were asked to play two games. One was the computer game Pong. The other was a variant of Nerf basketball with the hoop and backboard attached to the end of a robotic arm that moves it back and forth or up and down. Graduate students Changchun Liu and Karla Conn participated in the studies.
The researchers report that the physiological data they gathered can be used to develop an affective model for each individual that can predict his or her emotional states of liking, anxiety and engagement with an accuracy of better than 80 percent. Furthermore, they showed that this information can be used in real time to alter the game configuration in ways that significantly increase the children's degree of engagement.
"That's the part that really nailed me," says Stone, "that the robot can read the physiological cues of the person playing the game, control the distance and angle of the hoop, and that the person reported a more positive mood when the computer was responsive to his needs."
The ability to accurately monitor a child's emotional state is particularly important in treating ASD, Stone says: "Children with autism are not necessarily giving the kind of emotional cues that we know how to read. They are not necessarily good reporters of their inner feelings. If we know that the child is becoming upset or anxious, then we can help the child identify his or her own emotional state and implement strategies for monitoring and control. It is a concrete way to help them identify their own feelings."
One of the most encouraging results of their preliminary research was discovering that the affective model works accurately in different settings. The model was based on the readings they took as the children played Pong. The game was changed in several ways: Ball and paddle speeds were varied, and computer-based opponents of different skill levels were introduced. This allowed the researchers to induce emotions of interest, boredom, anxiety and engagement in each of the participants. The model was then used to predict how each child would react to changes in the computer game. When they switched to robot basketball, they found that the model's predictions were equally accurate.
"The model is about as good at identifying a child's emotional state as an experienced therapist. When a child gets a new therapist, as often happens, there is a learning curve as the new therapist gets to know the child, whereas the accuracy of the model should continue to improve over time," Sarkar points out.
A robot's ability to provide consistent and predictable responses should be particularly useful for treating ASD. Each child has individual triggers. For example, one child may not like direct eye contact. Another might be upset by loud voices and sounds. Yet another may react when people get too close. Once a particular trigger is identified, a robot could be programmed to increase the stimulus at such a gradual rate that the child doesn't notice it. The robot could also be programmed to back off when it senses that its responses are beginning to bother the child. In this fashion, it could build up the child's tolerance to the problem stimulus. "Robots can be programmed to respond with a consistency that is difficult for humans to achieve," Sarkar points out.
According to the autism expert, something that robots lack may also be an advantage in this setting. "I've always been interested in the idea of teaching social skills in a non-social situation that is less threatening. The children can be distracted by a lot of sensory stimuli coming at them. Social stimuli are particularly complex and can confuse them. So alternative methods of teaching that can subtract the social component could be very helpful as a beginning step," Stone says.
In the future, the researchers foresee technologies like robots and virtual reality environments as taking over some of the burden of the behavioral therapy that is one of the most time-consuming and expensive aspects of ASD treatment.
"This approach holds great promise," says Stone. "It will involve many steps and this is just the beginning. There are lots of different possible applications. So it is just a matter of finding the resources to explore them all."
The research was supported by a grant from the Marino Autism Research Institute.
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Adapted from materials provided by Vanderbilt University.

Safety device or just a must-have gizmo? The parent’s dilemma over pre-teen mobile

"The Tobi phone, unlike most mobiles, can block any numbers sending unwanted text messages"

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It is the modern parental dilemma: at what age should you let your child have his or her first mobile phone? The answer could soon be in single figures with the introduction of a device aimed at “pre-teens”.
Samsung’s Tobi phone, released yesterday at a cost of between £70 and £80, is supposed to ease the minds of concerned parents with several safety features that will make it easier to call parents in an emergency and stop children receiving bullying text messages.
But it is also designed to appeal to primary school pupils, coming in “sweet pink” or “loyal blue” colours with a choice of on-screen themes based on animated characters and the ability to customise the back of the phone with a range of colourful designs. Samsung said that it would be marketing the device at parents but family groups doubt this.
“I’ve always thought that there is a potential market for phones with reduced functionality that can block images and phone numbers,” said John Carr, secretary of the Children’s Charities’ Coalition on Internet Safety. “What is not a good idea is increasing the pressure on parents through marketing to buy more branded goods. In essence, it will be the kids who pick up on it.”
Sue Palmer, author of Detoxing Childhood, which gives advice to parents on how to steer children through the problems of growing up, said: “We have a huge amount of child protection legislation which is protecting their bodies, but nobody is thinking about their minds.
“They’re being brainwashed and leeched on to think that the most important thing in the world is consumption, and their parents are now being brought into the act.”
Samsung defended the phone, saying that the advertising was “aimed squarely at parents” and that it had gained the support of some parents’ groups, such as the Children’s Safety Education Foundation. “A least it gives the parent a chance to sit down and think about the safety issue,” it said.
The Tobi, unlike most phones, can block senders of text messages, so a child can choose to stop receiving messages from a given phone number. Experts pointed out, however, that the phone also has Bluetooth technology, which gives an alternative way for someone to send malicious and offensive messages that cannot be blocked.
Mr Carr said: “Some horrible pictures, sometimes pornographic ones, of kids on the toilet or in the changing rooms, are swapped through Bluetooth.”
Mobile phone makers are finding it increasingly difficult to sell their products because consumer demand is slowing and because the vast majority of people already own a phone. Many pre-teen children are among the last who do not. Research by the regulator Ofcom last year suggested that 65 per cent of girls and 61 per cent of boys between the ages of 8 and 11 owned or had access to a mobile phone. But in the same age range, only 22 per cent of boys and 40 per cent of girls used a mobile phone every day.
Others pointed to health concerns. In 2005 Sir William Stewart, then chairman of the Health Protection Agency and the National Radiological Protection Board, recommended that 9 to 14-year-olds should make only short calls and that younger children should never use mobile phones.

Small talk The Mickey Mouse phone
A planned Disney service aimed at 8 to 14-year-olds was scrapped because of an “adverse retail environment”

Teddyphone
“Child-safety” phone for four-year-olds programmed to call only four numbers.

Hello Kitty phone
Launched last summer in pink. Sanrio insisted that it was aimed at older women

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Source: Times archives