Atomic Antennas Transmit Quantum Information Across a Microchip

Atomic Antennas Transmit Quantum Information Across a Microchip

  12:48:00 AM    Science Lover

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The Austrian research group led by physicist Rainer Blatt suggests a fundamentally novel architecture for quantum computation. They have experimentally demonstrated quantum antennas, which enable the exchange of quantum information between two separate memory cells located on a computer chip. This offers new opportunities to build practical quantum computers.

Quantum antennae enable the exchange of quantum 
information between two separate memory cells located 
on a computer chip. (Credit: Harald Ritsch)

 

The researchers have published their work in the scientific journal Nature.

Six years ago scientists at the University of Innsbruck realized the first quantum byte -- a quantum computer with eight entangled quantum particles; a record that still stands. "Nevertheless, to make practical use of a quantum computer that performs calculations, we need a lot more quantum bits," says Prof. Rainer Blatt, who, with his research team at the Institute for Experimental Physics, created the first quantum byte in an electromagnetic ion trap. "In these traps we cannot string together large numbers of ions and control them simultaneously."

To solve this problem, the scientists have started to design a quantum computer based on a system of many small registers, which have to be linked. To achieve this, Innsbruck quantum physicists have now developed a revolutionary approach based on a concept formulated by theoretical physicists Ignacio Cirac and Peter Zoller. In their experiment, the physicists electromagnetically coupled two groups of ions over a distance of about 50 micrometers. Here, the motion of the particles serves as an antenna. "The particles oscillate like electrons in the poles of a TV antenna and thereby generate an electromagnetic field," explains Blatt. "If one antenna is tuned to the other one, the receiving end picks up the signal of the sender, which results in coupling." The energy exchange taking place in this process could be the basis for fundamental computing operations of a quantum computer.

Antennas amplify transmission

"We implemented this new concept in a very simple way," explains Rainer Blatt. In a miniaturized ion trap a double-well potential was created, trapping the calcium ions. The two wells were separated by 54 micrometers. "By applying a voltage to the electrodes of the ion trap, we were able to match the oscillation frequencies of the ions," says Blatt.

"This resulted in a coupling process and an energy exchange, which can be used to transmit quantum information." A direct coupling of two mechanical oscillations at the quantum level has never been demonstrated before. In addition, the scientists show that the coupling is amplified by using more ions in each well. "These additional ions function as antennas and increase the distance and speed of the transmission," says Rainer Blatt, who is excited about the new concept. This work constitutes a promising approach for building a fully functioning quantum computer.

"The new technology offers the possibility to distribute entanglement. At the same time, we are able to target each memory cell individually," explains Rainer Blatt. The new quantum computer could be based on a chip with many micro traps, where ions communicate with each other through electromagnetic coupling. This new approach represents an important step towards practical quantum technologies for information processing.

The quantum researchers are supported by the Austrian Science Fund FWF, the European Union, the European Research Council and the Federation of Austrian Industries Tyrol.

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ADHD Is a Genetic Disorder Children With ADHD More Likely to Have Missing or Duplicated Segments of DNA

ADHD Is a Genetic Disorder Children With ADHD More Likely to Have Missing or Duplicated Segments of DNA

  10:23:00 AM    Science Lover

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New research provides the first direct evidence that attention-deficit/hyperactivity disorder (ADHD) is a genetic condition. Scientists at Cardiff University found that children with ADHD were more likely to have small segments of their DNA duplicated or missing than other children.

In a new study, children with ADHD were more likely to have small segments of their DNA duplicated or missing than other children. (Credit: iStockphoto/Zmeel Photography)

The study also found significant overlap between these segments, known as copy number variants (CNVs), and genetic variants implicated in autism and schizophrenia, proving strong evidence that ADHD is a neurodevelopmental disorder -- in other words, that the brains of children with the disorder differ from those of other children.

The research, published in the journal The Lancet, was largely funded by the Wellcome Trust, with additional support from Action Medical Research, the Medical Research Council and the European Union.

"We hope that these findings will help overcome the stigma associated with ADHD," says Professor Anita Thapar. "Too often, people dismiss ADHD as being down to bad parenting or poor diet. As a clinician, it was clear to me that this was unlikely to be the case. Now we can say with confidence that ADHD is a genetic disease and that the brains of children with this condition develop differently to those of other children."

ADHD is one of the most common mental health disorders in childhood, affecting around one in 50 children in the UK. Children with ADHD are excessively restless, impulsive and distractible, and experience difficulties at home and in school. Although no cure exists for the condition, symptoms can be reduced by a combination of medication and behavioural therapy.

The condition is highly heritable -- children with ADHD are statistically more likely to also have a parent with the condition and a child with an identical twin with ADHD has a three in four chance of also having the condition. Even so, until now there has been no direct evidence that the condition is genetic and there has been much controversy surrounding its causes, which some people have put down to poor parenting skills or a sugar-rich diet.

The team at Cardiff University analysed the genomes of 366 children, all of whom had been given a clinical diagnosis of ADHD, against over 1,000 control samples in search of variations in their genetic make-up that were more common in children with the condition.

"Children with ADHD have a significantly higher rate of missing or duplicated DNA segments compared to other children and we have seen a clear genetic link between these segments and other brain disorders," explains Dr Nigel Williams. "These findings give us tantalising clues to the changes that can lead to ADHD."

The researchers found that rare CNVs were almost twice as common in children with ADHD compared to the control sample -- and even higher for children with learning difficulties. CNVs are particularly common in disorders of the brain.

There was also significant overlap between CNVs identified in children with ADHD and regions of the genome which are known to influence susceptibility to autism and schizophrenia. Whilst these disorders are currently thought to be entirely separate, there is some overlap between ADHD and autism in terms of symptoms and learning difficulties. This new research suggests there may be a shared biological basis to the two conditions.

The most significant overlap was found at a particular region on chromosome 16 which has been previously implicated in schizophrenia and other major psychiatric disorders and spans a number of genes including one known to play a role in the development of the brain .

"ADHD is not caused by a single genetic change, but is likely caused by a number of genetic changes, including CNVs, interacting with a child's environment," explains Dr Kate Langley. "Screening children for the CNVs that we have identified will not help diagnose their condition. We already have very rigorous clinical assessments to do just that."

Dr John Williams, Head of Neuroscience and Mental Health at the Wellcome Trust, which has supported Professor Thapar's work for ten years, says: "These findings are testament to the perseverance of Professor Thapar and colleagues to prove the often unfashionable theory that ADHD is a brain disorder with genetic links. Using leading-edge technology, they have begun to shed light on the causes of what is a complex and often distressing disorder for both the children and their families."

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A robot that can take decisions

A robot that can take decisions

  10:02:00 PM    Science Lover

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Robots that can make their own decisions have so far been confined to science fiction movies, but a child sized figure with big eyes and a white face is trying hard to turn fiction into reality.

Its name is iCub and scientists are hoping it will learn how to adapt its behavior to changing circumstances, offering new insights into the development of human consciousness.

Six versions of the iCub exist in laboratories across Europe, where scientists are painstakingly tweaking its electronic brain to make it capable of learning, just like a human child.

"Our goal is to really understand something that is very human - the ability to cooperate, to understand what somebody else wants us to do, to be able to get aligned with them and work together," said research director Peter Ford Dominey.

iCub is about 1 meter high, with an articulated trunk, arms and legs made up of intricate electronic circuits. It has a white face with the hint of a nose and big round eyes that can see and follow moving objects.

"Shall we play the old game or play a new one?" iCub asked Dominey during a recent experiment at a laboratory in Lyon, in southeastern France. Its voice was robotic, unsurprisingly, though it did have the intonation of a person asking a question. The "game" consisted of one person picking up a box, revealing a toy that was placed underneath. Then another person picked up the toy, before putting it down again. Finally, the first person put the box back down, on top of the toy.

Having watched two humans perform this action, iCub was able to join in the fun.

"The robot is demonstrating that it can change roles. It can play the role of either the first person in the interaction or the second," said Dominey, who receives European Union funding for his work with iCub.

"These robots will be a huge tool for analytical philosophy and philosophy of mind," said Dominey, whose background is in computational neuroscience - in layman's terms, building computer models for different brain functions.

Dominey said after years of research he had understood that such models needed to be "unleashed into the world" and given vision and motor control in order to interact with humans. "Is perception consciousness? The ability to understand that somebody has a goal, is that consciousness?" he asked. "These kinds of questions, we will be able to ask with much more precision because we can have a test bed, this robot, or zombie, that we can use to implement things," he said, describing working with iCub as "an outstanding pleasure."

In the short term, iCub could be used in hospitals to help patients in need of physiotherapy by playing games with them. In the longer term, iCub could gain enough autonomy to help around the house, making its own assessments of needs.

"People have their habits, loading their dishwasher, putting away their dishes. The goal is that the robot can become like a helper, just like a polite apprentice visitor would come into your house and begin to help you," said Dominey.

Anyone looking to cut down on their household chores will need to be patient, however. "It won't be for tomorrow. It's maybe in the next decade we will begin to see this kind of thing," said the scientist.

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