Major European Investment for Building Block Quantum Computer

(Originally published by TU Delft)

December 07, 2012

To construct the first quantum computer switch has long been the ambition of nano scientists Leo Kouwenhoven and Lieven Vandersypen from TU Delft and Carlo Beenakker from Leiden University. Since 2004, the trio has been working on the physical foundation of the potentially superfast quantum computer, with the support of NWO-FOM. They now feel the time is right to make the move towards producing a working computer circuit, partly based on the recently discovered Majorana particle. The European Union today announced they would finance the study with 15 million euros.

In their new lab, the scientists think they may counter the biggest obstacle to creating a quantum computer, quantum decoherence. Quantum particles have the unique property of being able to be or to do two things at the same time, but they are very sensitive to disturbances by other particles in their environment. This disruption causes the quantum state to be lost.

"The key question is: how do you ensure that this does not happen? This is very hard to achieve with one qubit, let alone in a circuit of thousands or even millions of qubits that are needed to build a quantum computer. If decoherence takes place in just one of those qubits, the whole quantum computation fails," says Leo Kouwenhoven. "The research in Delft and Leiden is now so advanced that we expect to build an experimental computer circuit in the coming years in which the quantum state is protected. Our recent discovery of the Majorana particle will play an important role. If this works, we will have the most important building block for the quantum computer."

Today's computers are based on the principle that numbers, called bits, may be 0 or 1. By constantly adding and subtracting, the computer ultimately reaches the result of a calculation. A quantum computer operates differently. It is based on quantum mechanics, where particles can have two properties simultaneously. The bits in a quantum computer (qubits) can be 0 and 1 at one and the same time. This allows a calculation, which would normally consist of successive steps, to be done all at once and therefore much quicker.

The research is funded by an ERC Synergy Grant, a new European subsidy for collaborating scientists. To combine all needed expertise, the team is complemented by the Delft researchers Erik Bakker, Leonardo DiCarlo, Ronald Hanson and Yuli Nazarov. An important part of the grant will be used for the realization of a new laboratory (see illustration). After three selection rounds, of the 700 applications that were submitted early 2012, only 1.5% were awarded a grant.