As if Quantum Computing didn’t have enough issues preventing it from being a workable solution already, new research at MIT has found that ionizing radiation from environmental radioactive materials and cosmic rays can and does interfere with the integrity of quantum computers. The research has been published in Nature: Impact of ionizing radiation on superconducting qubit coherence.
Quantum computers are super powerful because their basic building blocks qubit (quantum bit) is able to simultaneously exist as 0 or 1 (Yes, it makes no sense which is why Eisenstein called it ‘spooky action at a distance’) allowing it process a magnitude more operations in parallel than the regular computing systems. Unfortunately it appears that these qubits are highly sensitive to their environment and even minor levels of radiation emitted by trace elements in concrete walls and cosmic rays can cause them to loose coherence corrupting the calculation/data, this is called decoherence. The longer we can avoid decoherence the more powerful/capable the quantum computer. We have made significant improvements in this over the past two decades, from maintaining it for less than one nanosecond in 1999 to around 200 microseconds today for the best-performing devices.
As per the study, the effect is serious enough to limit the performance to just a few milliseconds which is something we are expected to achieve in the next few years. The only way currently known to avoid this issue is to shield the computer which means putting these computers underground and surrounding it with a 2 ton wall of lead. Another possibility is to use something like a counter-wave of radiation to cancel the incoming radiation similar to how we do noise-canceling. But that is something which doesn’t exist today and will require significant technological breakthrough before it is feasible.
“Cosmic ray radiation is hard to get rid of,” Formaggio says. “It’s very penetrating, and goes right through everything like a jet stream. If you go underground, that gets less and less. It’s probably not necessary to build quantum computers deep underground, like neutrino experiments, but maybe deep basement facilities could probably get qubits operating at improved levels.”
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“If we want to build an industry, we’d likely prefer to mitigate the effects of radiation above ground,” Oliver says. “We can think about designing qubits in a way that makes them ‘rad-hard,’ and less sensitive to quasiparticles, or design traps for quasiparticles so that even if they’re constantly being generated by radiation, they can flow away from the qubit. So it’s definitely not game-over, it’s just the next layer of the onion we need to address.”
Quantum Computing is a fascinating field but it really messes with your mind. So I am happy there are folks out there spending time trying to figure out how to get this amazing invention working and reliable enough to replace our existing Bit based computers.
Source: Cosmic rays can destabilize quantum computers, MIT study warns
– Suramya