Quantum-dot techniques have produced the first examples of quantum computing in a semiconductor at Purdue University. Researchers demonstrated that traditional GaAs fabrication equipment can be used to fashion quantum dots -— each representing a single qubit —- in domains as small as 50 nm in diameter.

Two of the dots were placed close enough for the team to observe quantum-spin interactions, a discovery that might lead to semiconductor-based quantum computers.

The researchers plan to put their chip to work by demonstrating that it can manifest quantum entanglement. If they can show entanglement, and if their measurements show that the dots are maintaining a coherence period long enough to do a quantum calculation, they plan to build a real quantum computer

In theory, tiny quantum dots can be used to create computers that fit hundreds of millions of qubits onto chips.