Quantum computers, desktop PCs that don't need cooling are coming soon?

Quantum computers

Today's superconducting quantum computers are huge and incredibly problematic machines. They must be isolated from anything that could disrupt an electron's spin off and ruin a calculation. This includes mechanical isolation, in extreme vacuum chambers, where only a few molecules could remain in a cubic meter or two of space. It includes electromagnetic forces - IBM, for example, surrounds its precious quantum bits, or qubits, with mu-metal - a metal alloy with high magnetic permeability - to absorb all magnetic fields.

Also, any atom with a temperature above absolute zero it is by definition in a state of vibration, and any temperature above 10-15 thousandths of a degree above absolute zero would shake the qubits enough to not allow them to maintain "consistency." So most state-of-the-art quantum computers must be cryogenically cooled using complex and expensive equipment for the qubits to hold their state for a certain period of time and become useful.

All these features are obviously not compatible with an inexpensive, portable or easily scalable computer. But an Australian-born startup says it has developed a quantum microprocessor that doesn't need any of those things. Right now it's the size of a rack unit, but it will soon be the size of a decent graphics card, and in a short time it will be small enough to fit mobile devices alongside traditional processors.

In the official documents of Quantum Brilliance, the company in question, we read that: "The quantum diamond computers at room temperature are made up of a series of processor nodes. Each processor node is composed of a vacant nitrogen center (NV), a defect in the diamond lattice consisting of a replacement nitrogen atom adjacent to a vacancy and a nuclear spin cluster - the intrinsic nuclear spin of nitrogen and up a ~ 4 neighboring 13C nuclear spin impurities. Nuclear spins act as computer qubits, while NV centers act as quantum buses that mediate the initialization and reading of qubits and intra- and inter-node multi-qubit operations. Quantum computing is controlled by radiofrequency, microwaves, optical and magnetic fields.

This field itself is not new - indeed, quantum qubits at room temperature have been around experimentally for more than 20 years. Quantum Brilliance's contribution to the field lies in understanding how to produce these little things in a precise and replicable way, as well as in miniaturizing and integrating the control structures needed to get information in and out of qubits - the two key areas that prevented these devices. to scale beyond a few qubits to date.

But how do they perform compared to traditional superconducting quantum computers? Extremely good, it seems. According to Mark Mattingley-Scott, one of the scientists involved in the project, "there is a value that can be applied to the ability of individual qubits to be useful, and that is the time of coherence. Superconducting qubits typically hold their coherence for perhaps 100 to 150 microseconds. In diamonds at room temperature, we are talking about milliseconds. Like, a thousand times longer, and that means you can do a lot more. This is part of the equation; the other part is the error rates. Qubits, basically, have an error rate, even before they lose coherence and drop by sheer randomness. The error rates we get with vacant nitrogen qubits are very, very good. ”

So when will any of these things reach the historic milestone of quantum supremacy, becoming more powerful than any supercomputer at solving specific laboratory tests? In this case, this is not the goal. "We have a clear five-year roadmap to produce something we call quantum utility," said company co-founder Mark Luo.

"Other systems can't be miniaturized, we can miniaturize. So for us it is about producing a quantum computer or quantum accelerator that outperforms a classical computer of the same size, weight and power. It is surpassing components within a supercomputer rather than overtaking entire supercomputers in order to provide commercial utility. "

Diamond quantum accelerators at room temperature could therefore become just another component for a PC, offering quantum functionality when there is an advantage. Quantum Brilliance's vision is in fact to make qubits a component that can be easily integrated into any computer, something like today's high-end graphics cards, mass-produced to work in a wide range of systems at low unit costs. Software developers could therefore use traditional or quantum computing only where each is truly advantageous.