|Image Source: Joint Quantum Institute|
The first quantum-logic device made from silicon has been unveiled by researchers in Australia and Japan. Their controlled-not (CNOT) gate, which is a fundamental component of a quantum computer, was made using conventional semiconductor manufacturing processes. The researchers now plan to scale up the technology to create a full-scale quantum-computer chip.
|Spin doctors: Menno Veldhorst (left) and Andrew Dzurak with the equipment used to cool and monitor their CNOT gate.|
Quantum computers exploit the weird laws of quantum mechanics to perform some calculations much faster than conventional computers – at least in principle. The main challenge facing physicists trying to build quantum computers is how to preserve fragile quantum bits (qubits) of information, which tend to deteriorate rapidly in real-world devices.
One approach is to use the spin of the electron – which can point up or down – as a qubit. Spin qubits have been made from tiny pieces of semiconductor called quantum dots, and quantum-logic devices have been made by coupling these qubits together. Unfortunately, the spin states in these devices rapidly deteriorate – or "decohere" – by interacting with nuclear spins in the compound-semiconductor materials normally used to make quantum dots.
Physics World: Silicon quantum logic gate is a first, Hamish Johnston