Solid-state quantum computer to start at a temperature above Kelvin

Two groups of researchers independently demonstrated the qubits based on silicon quantum dots operating at temperatures above one Kelvin. One group has also implemented a universal quantum logic on your dvuhserijnom processor. At these temperatures solid-state quantum computing becomes simple and, most importantly, cheap. Both works are published in the journal Nature: 1, 2.

Quantum computers can outperform their classical counterparts in many tasks, from simulations of complex molecules before decomposition of large numbers into Prime factors. However, to solve useful tasks necessary to control millions of qubits that can be a serious engineering problem. Promising superconductors and quantum dots operate at a temperature of tens of millikelvin, and each qubit is controlled by a separate line. When you increase the number of qubits grows and the complexity of the controlling system, which, in turn, heats the CPU, and destroys coherence of the quantum system. Unfortunately, modern cooling devices, cryostats dissolution, not able to cope with this amount of heat, at temperatures of the order of millikelvins the cooling capacity of the cryostat is very low.

One possible solution lies in increasing the working temperature of the qubits to a few degrees Kelvin, enabling the use of pure helium which is much cheaper than the mixes used in cryostats dissolution. Moreover, pure helium has a much higher cooling capacity.

Two groups of physicists under the leadership of Professor Jurica (A. S. Dzurak) and Professor Windhorst (M. Veldhorst) demonstrated qubits based on quantum dots in silicon, operating at temperatures above one Kelvin.

The group of Professor Jurica could very well isolate the qubit from external noise, making it possible to raise the operating temperature to 1.5 Kelvin with a small loss of coherence.

In the experiment, physicists have used two qubit in quantum dots. One of the qubits used for the logical operations and the other was used for non-invasive measurement. Both of the qubit was controlled by microwave fields.

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