Physicists Move One Step Closer to Quantum Computer

Rice University physicists have created a tiny "electron superhighway" that could one day be useful for building a quantum computer, a new type of computer that will use quantum particles in place of the digital transistors found in today's microchips.In a recent paper in Physical Review Letters, Rice physicists Rui-Rui Du and Ivan Knez describe a new method for making a tiny device called a "quantum spin Hall topological insulator." The device, which acts as an electron superhighway, is one of the building blocks needed to create quantum particles that store and manipulate data.

Today's computers use binary bits of data that are either ones or zeros. Quantum computers would use quantum bits, or "qubits," which can be both ones and zeros at the same time, thanks to the quirks of quantum mechanics.

This quirk gives quantum computers a huge edge in performing particular types of calculations, said Du, professor of physics and astronomy at Rice. For example, intense computing tasks like code-breaking, climate modeling and biomedical simulation could be completed thousands of times faster with quantum computers.

"In principle, we don't need many qubits to create a powerful computer," he said. "In terms of information density, a silicon microprocessor with 1 billion transistors would be roughly equal to a quantum processor with 30 qubits."

In the race to build quantum computers, researchers are taking a number of approaches to creating qubits. Regardless of the approach, a common problem is making certain that information encoded into qubits isn't lost over time due to quantum fluctuations. This is known as "fault tolerance."

The approach Du and Knez are following is called "topological quantum computing." Topological designs are expected to be more fault-tolerant than other types of quantum computers because each qubit in a topological quantum computer will be made from a pair of quantum particles that have a virtually immutable shared identity. The catch to the topological approach is that physicists have yet to create or observe one of these stable pairs of particles, which are called "Majorana fermions" (pronounced MAH-yor-ah-na FUR-mee-ons).

The elusive Majorana fermions were first proposed in 1937, although the race to create them in a chip has just begun. In particular, physicists believe the particles can be made by marrying a two-dimensional topological insulator -- like the one created by Du and Knez -- to a superconductor.

Topological insulators are oddities; although electricity cannot flow through them, it can flow around their narrow outer edges. If a small square of a topological insulator is attached to a superconductor, Knez said, the elusive Majorana fermions are expected to appear precisely where the materials meet. If this proves true, the devices could potentially be used to generate qubits for quantum computing, he said.

Knez spent more than a year refining the techniques to create Rice's topological insulator.

How the Brain Makes Memories

The brain learns through changes in the strength of its synapses -- the connections between neurons -- in response to stimuli. Now, in a discovery that challenges conventional wisdom on the brain mechanisms of learning, UCLA neuro-physicists have found there is an optimal brain "rhythm," or frequency, for changing synaptic strength. And further, like stations on a radio dial, each synapse is tuned to a different optimal frequency for learning.The findings, which provide a grand-unified theory of the mechanisms that underlie learning in the brain, may lead to possible new therapies for treating learning disabilities.

The study appears in the current issue of the journal Frontiers in Computational Neuroscience.

"Many people have learning and memory disorders, and beyond that group, most of us are not Einstein or Mozart," said Mayank R. Mehta, the paper's senior author and an associate professor in UCLA's departments of neurology, neurobiology, physics and astronomy. "Our work suggests that some problems with learning and memory are caused by synapses not being tuned to the right frequency."

A change in the strength of a synapse in response to stimuli -- known as synaptic plasticity -- is induced through so-called "spike trains," series of neural signals that occur with varying frequency and timing. Previous experiments demonstrated that stimulating neurons at a very high frequency (e.g., 100 spikes per second) strengthened the connecting synapse, while low-frequency stimulation (e.g., one spike per second) reduced synaptic strength.

These earlier experiments used hundreds of consecutive spikes in the very high-frequency range to induce plasticity. Yet when the brain is activated during real-life behavioral tasks, neurons fire only about 10 consecutive spikes, not several hundred. And they do so at a much lower frequency -- typically in the 50 spikes-per-second range.

In other words, said Mehta, "spike frequency refers to how fast the spikes come. Ten spikes could be delivered at a frequency of 100 spikes a second or at a frequency of one spike per second."

Until now, researchers had been unable to conduct experiments that simulated more naturally occurring levels. But Mehta and co-author Arvind Kumar, a former postdoctoral fellow in his lab, were able to obtain these measurements for the first time using a sophisticated mathematical model they developed and validated with experimental data.

Contrary to what was previously assumed, Mehta and Kumar found that when it comes to stimulating synapses with naturally occurring spike patterns, stimulating the neurons at the highest frequencies was not the best way to increase synaptic strength.

When, for example, a synapse was stimulated with just 10 spikes at a frequency of 30 spikes per second, it induced a far greater increase in strength than stimulating that synapse with 10 spikes at 100 times per second.

"The expectation, based on previous studies, was that if you drove the synapse at a higher frequency, the effect on synaptic strengthening, or learning, would be at least as good as, if not better than, the naturally occurring lower frequency," Mehta said. "To our surprise, we found that beyond the optimal frequency, synaptic strengthening actually declined as the frequencies got higher."

The knowledge that a synapse has a preferred frequency for maximal learning led the researchers to compare optimal frequencies based on the location of the synapse on a neuron. Neurons are shaped like trees, with the nucleus being the base of the tree, the dendrites resembling the extensive branches and the synapses resembling the leaves on those branches.

When Mehta and Kumar compared synaptic learning based on where synapses were located on the dendritic branches, what they found was significant: The optimal frequency for inducing synaptic learning changed depending on where the synapse was located. The farther the synapse was from the neuron's cell body, the higher its optimal frequency.

India unveils $35 tablet computer - world’s cheapest tablet PC

 The world’s cheapest tablet PC, priced at around Rs. 1,200, will now be available to students in the country as part of the government’s programme to expand education through information technology.

The nation of 1.2 billion people announced plans to sell government-subsidized tablets priced at $35 to thousands of needy villagers in the countryside. Named Aakash, or "sky" in Hindi, the tablet has been touted as the cheapest of its kind in the world.

The device followed years of efforts by developer Datawind and the Indian government to design and build a $10 computer that could help millions get online, many for the first time. That ambitious goal wasn't quite met -- the government is actually paying $45 for each tablet from Datawind, and subsidizing it for distribution to students and teachers in the coming months.

But $45 is still a mere fraction of the cost of other blockbuster tablets: the basic iPad tablet costs $499, and the upcoming Amazon Kindle Fire is priced at $199.

The Android-powered device will have a color touchscreen and be capable of handling more basic computing tasks such as word processing, Web browsing and video conferencing.

The company sold 16 million iPhones in the first quarter of 2011.  

Digital diviner who made computing personal- Steve Jobs

Steve Jobs, the 56-year-old iconic co-founder of Apple, breathed his last on Wednesday.

“Technology alone is not enough,” Steve Jobs, the 56-year-old iconic co-founder of Apple, declared last year while unveiling the iPad. “It's technology married with liberal arts, married with humanities, that yields the results that make our hearts sing.” On Wednesday, his own heart stilled as he lost the battle with pancreatic cancer; but the chord he first struck in his garage-based computer venture three decades ago by linking the drive for innovation with the consumer's desire for utilitarian technology will continue to move the world of computing and electronics for many years to come.

A pioneer who made Silicon Valley synonymous with entrepreneurial spirit, innovation and technological excellence, Jobs, launched Apple with his friend, Steve Wozniak, in 1976.

Jobs “died peacefully surrounded by his family,” his wife, Laurene, and four children, said in a statement. In a tribute, Apple said it had “lost a creative and visionary genius and the world [had] lost an amazing human being.”

Tributes poured in from around the world and fans flocked to Apple stores in several countries to mourn the passing of the “leading light” of the digital age, as one industry CEO described him. Flags flew at half mast at the headquarters of the company at Cupertino, California.

Steve Jobs was diagnosed with a rare form of treatable pancreatic cancer in 2003, and underwent surgery. He had a liver transplant six years later with doctors giving him an “excellent prognosis.” In August this year, Jobs stepped down as the CEO of Apple, making way for Tim Cook to take over. He declared that the day had come when he could no longer meet his duties.

U.S. President Barack Obama described Steve Jobs as among the greatest of American innovators — brave enough to think differently, bold enough to believe he could change the world, and talented enough to do it.

Bill Gates, co-founder of Microsoft, said in a statement, “For those of us lucky enough to get to work with Steve, it's been an insanely great honor. I will miss Steve immensely.”

Apple unveils iPhone 4S

Apple Inc. unveiled a new iPhone on Tuesday that is faster and more powerful but stops short of a more radical upgrade. It said Sprint customers will now be able to use one.

The new iPhone 4S has an improved camera with a higher-resolution sensor. The processor is faster, which helps run smoother, more realistic action games. It’s also a “world phone,” which means that Verizon iPhones will be useable overseas, just as AT&T iPhones already are.

There had been speculation that Apple would reveal a more radical revision of the phone, an “iPhone 5.” The no-show leaves room for speculation that Apple will reveal a new model in less than a year, perhaps one equipped to take advantage of Verizon’s and AT&T’s new high-speed data networks.

Apple is including a “personal assistant” application called Siri in the iPhone 4S. It responds to spoken questions and commands such as “Do I need an umbrella today?” It’s an advanced version of speech-recognition apps found on other phones.

The new iPhone also comes with new mobile software that includes such features as the ability to sync content wirelessly, without having to plug the device to a Mac or Windows machine.

The iPhone announcement came during Apple’s first major product event in years without Steve Jobs presiding. New CEO Tim Cook led the show after Jobs, who has been battling health problems, resigned from the post in August.

Mr. Cook, wearing a navy blue button-down shirt and jeans, opened by calling his nearly 14-year tenure at Apple “the privilege of a lifetime.” Those in the audience clapped as he entered, but the reaction seemed more muted than what Mr. Jobs had recently received.

Mr. Cook said the latest iPhone, which came out in June 2010, sold more quickly than previous models, but the iPhone still has just 5 per cent of the worldwide handset market. Apple is hoping to grow that with the new model.

Apple’s new mobile software, iOS 5, will also be available on October 12 for existing devices the iPhone 4 and 3GS,

Google Earth reaches 1 billion downloads

 The planet’s computer users have downloaded Google Earth more than 1 billion times, the company said on Wednesday in an official blog.

The programme, which offers users a customisable and navigable rendering of the world from Mars to the ocean floor, was bought by Google in 2004 when it acquired the company Keyhole, which invented the first version of the software in 2001.

To celebrate the one-billionth download, Google launched a new website at www.OneWorldManyStories.com, which features “people all over the world who use Google Earth to follow their dreams, discover new and distant places, or make the world a better place.”

“While it’s inspiring to see how Google Earth has touched the lives of so many, we know the best is yet to come,” said Brian McClendon, vice-president of Engineering, Google Earth and Maps.

Jobs was “leading light” of digital age

we can describe Steve Jobs as the “leading light” in the digital age.


Few companies have felt Apple’s rise more so than Japan’s Sony, whose iconic Walkman transformed the music listening experience in the 1980s. But it was slow to embrace the shift to digital downloads.



The Walkman was no match for Apple’s iPod when it launched in 2001.



But Mr. Jobs himself was deeply influenced by Sony and Japan. He counted Sony founder Akio Morita as one of his mentors and was said to have been inspired by the Walkman. “The digital age has lost its leading light, but Steve’s innovation and creativity will inspire dreamers and thinkers for generations,”   Sony Corp. President and Chief Executive Howard Stringer said in a one-sentence statement.



Person of great vision: Acer


Taiwan’s Acer Inc., a leading PC vendor, calls Steve Jobs a “person of great vision, innovation and leadership” as it remembered the late Apple founder’s “huge influence” on the industry.

In a Thursday statement, Acer said Mr. Jobs’ death “is a great loss to Apple as well as the industry.”

Acer was once the world’s No. 3 PC vendor, but the advent of Apple’s iPads cut into PC sales and forced Acer to change directions to meet the challenge early this year.

Mr. Jobs’ death did not have an immediate impact on Hon Hai Industry Precision Co., a key producer of iPhones and iPads. Its share prices rose about 2 percent early Thursday on expectations that recent Apple price cuts will bolster the Taiwanese company’s revenues.



Innovative spirit: Samsung

Samsung is calling rival Steve Jobs an “innovative spirit” who will be remembered forever.

Samsung said Thursday that Mr. Jobs “introduced numerous revolutionary changes to the information technology industry.”

The announcement of Mr., Jobs’ death came a day after Samsung said it would file court injunctions in France and Italy seeking to block the sale of Apple’s latest iPhone. The smartphone giants are locked in an intensifying patent fight.

Samsung says Mr. Jobs’ “innovative spirit and remarkable accomplishments will forever be remembered by people around the world.”

The companies have been at odds since April when Apple took legal actions claiming Samsung’s Galaxy line of smartphones and tablet computers copy the iPhone and iPad.Sony Corp. President and Chief Executive Howard Stringer described Steve Jobs as the “leading light” in the digital age.


Few companies have felt Apple’s rise more so than Japan’s Sony, whose iconic Walkman transformed the music listening experience in the 1980s. But it was slow to embrace the shift to digital downloads.



The Walkman was no match for Apple’s iPod when it launched in 2001.



But Mr. Jobs himself was deeply influenced by Sony and Japan. He counted Sony founder Akio Morita as one of his mentors and was said to have been inspired by the Walkman. “The digital age has lost its leading light, but Steve’s innovation and creativity will inspire dreamers and thinkers for generations,” Mr. Stringer said in a one-sentence statement.