Home  |  Top News  |  Most Popular  |  Video  |  Multimedia  |  News Feeds  |  Feedback
  Medicine  |  Nature & Earth  |  Biology  |  Technology & Engineering  |  Space & Planetary  |  Psychology  |  Physics & Chemistry  |  Economics  |  Archaeology
Top > Technology & Engineering > Contextuality Puts the 'Magic' in… >
Contextuality Puts the 'Magic' in Quantum Computing

Published: June 11, 2014.
By Canadian Institute for Advanced Research

A new theoretical advance explains where the power of quantum computation comes from, and will help researchers design and build better computers and algorithms.

The strange properties of quantum mechanics give quantum computers the potential to perform some computations exponentially faster than conventional computers. But where the extra power comes from – and how best to take advantage of it – is in many ways still an open question.

A new paper in the journal Nature by CIFAR Fellow Joseph Emerson of the program in Quantum Information Science, along with colleagues at the Institute of Quantum Computing at the University of Waterloo, is a step towards solving the questions.

The paper shows that a quantum property called contextuality is the key. Contextuality refers to the fact that in quantum systems, a measurement will necessarily affect the thing being measured. For instance, if you want to measure the spin of a particle, it's wrong to think that there is a "real" spin just waiting to be revealed. Instead, the very act of measuring the spin helps determine what it will be.

"One way of thinking about contextuality is that inevitably measurements involve some kind of disturbance. I'm not just learning about some definite property the system had prior to the measurement. I can be learning about some property the system had, but only in a way that depends on how I did the measurement."

One of the leading approaches for quantum computing uses a technique called fault-tolerant stabilizer computation. It's a way of correcting errors that occur in quantum computers as the quantum states interact with the environment. By using a process called "magic-state distillation," quantum computers can be made to function dependably despite the noise introduced by the environment.

Emerson's paper shows that the only kinds of "magic states" that will yield quantum computational power are those that rely on contextuality.

"Ultimately this should be a tool for experimentalists, to set the bar for what they have to achieve if they want to build a quantum computer that is useful, perhaps as a litmus test for a quantum computer's viability," Emerson says.

Although the mathematical proof of the power of contextuality is limited for now to a particular kind of quantum computation, Emerson thinks that future work might show that it's a general feature of all quantum computation.

Emerson says that the result builds on earlier work from a collaboration with CIFAR Senior Fellow Daniel Gottesman (Perimeter Institute), which grew out of contact they had through the CIFAR program.

"The CIFAR quantum information network and CIFAR funding were both instrumental to developing this result, which was a collective effort from several members of my research group," Emerson says.

Show Reference »

Translate this page: Chinese French German Italian Japanese Korean Portuguese Russian Spanish

All comments are reviewed before being posted. We cannot accept messages that refer a product, or web site.If you are looking for a response to a question please use our another feedback page.
Related »


Quantum Computers: Trust Is Good, Proof Is Better
By University of Vienna

UCSB Physicists Demonstrate the Quantum Von Neumann Architecture
By University of California - Santa Barbara

UCSB Researchers Make Headway in Quantum Information Transfer Via Nanomechanical Coupling
By University of California - Santa Barbara
Diamonds Are a Quantum Computer's Best Friend
By Vienna University of Technology
The Quantum Computer is the Holy Grail of quantum technology. Its computing power would eclipse even the fastest classical computers we have today. A team of researchers from TU …

Scientists Find Way to Maintain Quantum Entanglement in Amplified Signals
By Moscow Institute of Physics and Technology
Dramatic Simplification Paves the Way for Building a Quantum Computer
By University of Bristol
Dr Xiao-Qi Zhou and colleagues at the University of Bristol's Centre for Quantum Photonics and the University of Queensland, Australia, have shown that controlled operations — ones that are …

Quantum Manipulation: Filling the Gap Between Quantum And Classical World
By Science China Press
Into the Quantum Internet at the Speed of Light
By University of Innsbruck
Thanks to the strange laws of quantum mechanics, quantum computers would be able to carry out certain computational tasks much faster than conventional computers. Among the most promising technologies …
A Study Lays the Foundations for Tomographics Applied to the Quantum World
By Carlos III University of Madrid
Any physical system - be it an electron, a molecule of water, a virus, a human being, a whole planet – is characterized at each moment in time distinctively …
More » 
© Newsline Group  |  About  |  Privacy Policy  |  Feedback  |  Mobile  |  Japanese Edition
All contents are copyright of their owners except U.S. Government works. U.S. Government works are assumed to be in the public domain unless otherwise noted. Everything else copyright ScienceNewsline.