Scalable silicon qubits operate under practical conditions

PhD students Luca Petit and Gertjan Eenink working at the hot qubit setup.v

QuTech, a collaboration between TU Delft and TNO, has managed to control qubits in silicon at temperatures over 50 times higher than previously. The increase to practical temperatures represents a crucial leap towards a functional quantum computer.

The separation between qubits and electronics causes problems when scaling up the number of qubits. Currently, a separate cable is needed to connect each qubit to its controlling electronics. This is no longer feasible when making the millions of qubits needed to obtain a working quantum computer.

The challenge is to find a temperature at which both the qubits and the electronics can function. Researchers make fast progress in reducing the temperature at which the electronics can operate. For example, QuTech and Intel recently developed a chip that can control qubits at low temperatures.

This is the first time that it has been possible to control qubits in silicon at a higher temperature, and above one Kelvin. The increase in temperature may seem like a small step, but it’s a huge leap when it comes to the available cooling capacity. Furthermore, at these temperatures the qubits no longer have to work in a vacuum, but can be immersed in a liquid, which makes everything much more practical.

The researchers have published their findings in Nature.

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