Scientists realize quantum bit with a bent nanotube

July 29, 2013
Scientists realize quantum bit with a bent nanotube

One of the biggest challenges in quantum science is to build a functioning quantum bit, the basic element for the quantum computer. An important theoretical candidate for such a quantum bit is using a bent carbon nanotube. Scientists at the Delft University of Technology and the Foundation for Fundamental Research on Matter (FOM), led by Professor Leo Kouwenhoven, have succeeded for the first time to create a working quantum bit using a carbon nanotube. On July 28 they published their results in Nature Nanotechnology.

Quantum computer

Quantum computers have the advantage that they can be much faster than "ordinary" supercomputers for various calculations. An ordinary computer bit has the value '1 'or '0', but a quantum bit uses the state of a single electron, which due to the extraordinary properties of the quantum world can take both values at the same time. "We call that a 'superposition''' says PhD student Fei Pei who carried out part of the measurements. "The main problem that quantum physicists have to deal with is that the superposition can be disturbed quickly by external factors, for instance by other particles around the quantum bit."

Bent tubes

Carbon nanotubes of a few in diameter have exceptional properties that make them a very suitable material for hosting quantum bits, but so far no one could manipulate and 'read' a single electron in a nanotube. The scientists from Delft have achieved that. They were inspired by the work of colleagues from Copenhagen who showed in 2010 theoretically that the of an electron can be controlled in a bent nanotube, and carried on their own work from 2012. Back then the Delft scientists showed how to read the electron quantum states in a nanotube. Putting both ideas together created a 'functioning' quantum bit.

"The next challenge would be to improve the stability of this as currently we can not maintain the superposition state long enough, "said Pei. "We will now focus on reducing the disturbance, so to extend the lifetime of the superposition".

Explore further: Efficient distributed quantum computing

More information: Nature Nanotechnology DOI: 10.1038/nnano.2013.140

Related Stories

Efficient distributed quantum computing

February 21, 2013

(—A quantum computer doesn't need to be a single large device but could be built from a network of small parts, new research from the University of Bristol has demonstrated. As a result, building such a computer ...

Hide and seek with a quantum compass

March 11, 2013

How would you look for something that can be in two 'places' at once? The answer, according to Oxford University research into a quantum phenomenon called superposition, seems to be to ask where it isn't rather than where ...

Quantum computers counting on carbon nanotubes

March 21, 2013

Carbon nanotubes can be used as quantum bits for quantum computers. A study by physicists at the Technische Universitaet Muenchen has shown how nanotubes can store information in the form of vibrations. Up to now, researchers ...

Recommended for you

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

'Material universe' yields surprising new particle

November 25, 2015

An international team of researchers has predicted the existence of a new type of particle called the type-II Weyl fermion in metallic materials. When subjected to a magnetic field, the materials containing the particle act ...

Exploring the physics of a chocolate fountain

November 24, 2015

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, answering the age-old question of why the falling 'curtain' of chocolate surprisingly pulls inwards rather than going straight ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.