Synergy funding for Delft-Leiden quantum computer workshop
Leiden nano-physicist Carlo Beenakker is one of a trio of scientists from Delft and Leiden who have been awarded EUR 15 million of European funding to set up a lab and get the quantum computer off the ground. The Majorana particle is going to help them here.
The two applicants from Delft, Leo Kouwenhoven and Lieven Vandersypen, have been working with Beenakker since 2004 on the design of a quantum computer, with the support of the NWO's FOM foundation. The ‘synergy’ of this new project is that everything – from theoretical quantum physics right up to the ‘nuts and bolts’ of a miniature quantum computer – is under one roof (Delft). The students from Beenakker’s group will consequently also spend some of their time in Delft testing their theories.
In their new lab the three will hopefully be able to overcome the biggest stumbling block to building a quantum computer: quantum decoherence. This is when quantum particles lose the freedom to be able to do two things simultaneously. To prevent this loss, you need to protect the particles from interference from the environment that knocks them back into line.
The researchers are therefore going to build a miniature quantum circuit based on important discoveries that they have made in recent years, including the Majorana particle. Within this circuit they want to create a protective environment for the particles that are in a state of quantum coherence.If it works, it could be the first building block for a whole complex of circuits that together form a quantum computer.
|Today’s computers are based on the principle that numbers, known as bits, can be 0 or 1. By repeatedly adding and subtracting, a computer finally arrives at the solution to a calculation. A quantum computer works differently. It is based on quantum mechanics, whereby particles can have two properties at the same time. It might sound strange but electrons in atoms and molecules can be in two places at the same time or move both clockwise and anticlockwise. According to the laws of quantum mechanics, it is not either-or but both-and. The bits in a quantum computer (qubits) can be 0 and 1 at the same time. This makes it possible to make a calculation in one go that would normally consist of separate consecutive steps.||
About the ERC Synergy Grant
But a quantum computer is much more than just a super-fast computer. It is untroubled by the classic laws of science that limit the possibilities of today’s computers. It could therefore serve as a simulation instrument that would make a whole new form of material design possible. A quantum computer could also help find a way to induce superconductivity at room temperature, which would make energy transport without energy loss possible. With a super-computer biologists would be able to predict how proteins are folded and use this knowledge for medical applications.
Building a quantum computer is extremely difficult, because the state in which a particle can simultaneously have two properties is extremely fragile. The merest thing can upset this state of what is known as superposition. The most important question is therefore how you ensure that this does not happen. It is hard enough to achieve this with one qubit let alone in the circuit of thousands or millions of qubits that make up a quantum computer. If only one of those qubits falls victim to decoherence, this is enough to cause the whole quantum calculation to fail. This is therefore the great challenge the researchers are facing: how to build an enormous, complex system in which it is still possible to use delicate quantum superpositions.
(5 December 2012)
- Millions for Leiden physicists and education specialists in Gravitation programme
- Casimir Research School
- Synergy Grants
Physics (information in Dutch)
Fundamentals of Science is one of the six research themes at Leiden University.