Quantum computing leaps forward using silicon

25 Jun 2010

A breakthrough in quantum computing shows that its very nature – the ability for an electron to exist in two places at once – can be implemented using plain old silicon.

Researchers from the University of Surrey in the UK have been looking at how it is possible to make a quantum computer but in an affordable way.

The science behind quantum computing looks at how quantum properties can be used to represent data, ie in qubits or quantum bits, and these researchers have published an article in Nature showing how they have managed to create a simple working model out of the same material from which ordinary computer chips are made.

Real-life example of Schrodinger’s cat theory

You’ve probably heard of Schrodinger’s cat – the only moggy to be both alive and dead at the same time on account of being in a box that we have no way of seeing through and therefore no way of knowing said cat’s state of existence.

This silicon implementation of quantum computing is a real-life example of Schrodinger’s cat.

“This is a real breakthrough for modern electronics and has huge potential for the future,” explained Professor Ben Murdin, Photonics Group Leader at the University of Surrey.

“Lasers have had an ever increasing impact on technology, especially for the transmission of processed information between computers, and this development illustrates their potential power for processing information inside the computer itself.

Professor Murdin and his team are using a far-infrared, very short, high-intensity pulse from the Dutch-UK FELIX laser to put an electron orbiting within silicon into two states at once. This is known as a quantum superposition state.

“We then demonstrated that the superposition state could be controlled so that the electrons emit a burst of light at a well-defined time after the superposition was created. The burst of light is called a photon echo; and its observation proved we have full control over the quantum state of the atoms,” he added.

Silicon-based quantum computers

With these inroads made it may not be very long before a silicon-based quantum computer can be constructed, allowing for far more powerful and efficient calculations than standard computers that exist today.

“Quantum computers can solve some problems much more efficiently than conventional computers – and they will be particularly useful for security because they can quickly crack existing codes and create un-crackable codes,” Professor Murdin pointed out.

“The next generation of devices must make use of these superpositions to do quantum computations. Crucially our work shows that some of the quantum engineering already demonstrated by atomic physicists in very sophisticated instruments called cold atom traps can be implemented in the type of silicon chip used in making the much more common transistor.”