Scientists rotate electron spin with electric field

Nov 01, 2007
Scientists rotate electron spin with electric field
An electron microscope photo of a nanostructure similar to that used in the experiment. The light-grey colors show the metal structure (made of gold) used to create an electric trap (white lines) for the electrons. A voltage (V) that changes with time is applied to the rightmost piece of metal. As a result, the electron, which is locked in the right trap, feels an electric field. This electric field causes the electron to move (white dotted line), so that the position of the electron changes with time. Credit: TU Delft

Researchers at the Delft University of Technology’s Kavli Institute of Nanoscience and the Foundation for Fundamental Research on Matter (FOM) have succeeded in controlling the spin of a single electron merely by using electric fields. This clears the way for a much simpler realization of the building blocks of a (future) super-fast quantum computer.

The scientists will publish their work in Science Express on Thursday 1 November.

Controlling the spin of a single electron is essential if this spin is to be used as the building block of a future quantum computer. An electron not only has a charge but, because of its spin, also behaves as a tiny magnet.

In a magnetic field, the spin can point in the same direction as the field or in the opposite direction, but the laws of quantum mechanics also allow the spin to exist in both states simultaneously. As a result, the spin of an electron is a very promising building block for the yet-to-be-developed quantum computer; a computer that, for certain applications, is far more powerful than a conventional computer.

At first glance it is surprising that the spin can be rotated by an electric field. However, we know from the Theory of Relativity that a moving electron can ‘feel’ an electric field as though it were a magnetic field. Researchers Katja Nowack and Dr. Frank Koppens therefore forced an electron to move through a rapidly-changing electric field. Working in collaboration with Prof. Yuli V. Nazarov, theoretical researcher at the Kavli Institute of Nanoscience Delft, they showed that it was indeed possible to turn the spin of the electron by doing so.

The advantage of controlling spin with electric fields rather than magnetic fields is that the former are easy to generate. It will also be easier to control various spins independently from one another - a requirement for building a quantum computer - using electric fields. The team, led by Dr. Lieven Vandersypen, is now going to apply this technique to a number of electrons.

Source: Delft University of Technology

Explore further: The unifying framework of symmetry reveals properties of a broad range of physical systems

add to favorites email to friend print save as pdf

Related Stories

Magnetic memories on the right track

4 hours ago

Computer hard drives store data by writing magnetic information onto their surfaces. In the future, magnetic effects may also be used to improve active memory in computers, potentially eliminating the need ...

Molecular engineers record an electron's quantum behavior

Aug 14, 2014

A team of researchers led by the University of Chicago has developed a technique to record the quantum mechanical behavior of an individual electron contained within a nanoscale defect in diamond. Their technique ...

Recommended for you

What time is it in the universe?

Aug 29, 2014

Flavor Flav knows what time it is. At least he does for Flavor Flav. Even with all his moving and accelerating, with the planet, the solar system, getting on planes, taking elevators, and perhaps even some ...

Watching the structure of glass under pressure

Aug 28, 2014

Glass has many applications that call for different properties, such as resistance to thermal shock or to chemically harsh environments. Glassmakers commonly use additives such as boron oxide to tweak these ...

Inter-dependent networks stress test

Aug 28, 2014

Energy production systems are good examples of complex systems. Their infrastructure equipment requires ancillary sub-systems structured like a network—including water for cooling, transport to supply fuel, and ICT systems ...

Explainer: How does our sun shine?

Aug 28, 2014

What makes our sun shine has been a mystery for most of human history. Given our sun is a star and stars are suns, explaining the source of the sun's energy would help us understand why stars shine. ...

User comments : 0