• Question: why do quantum computers have to be at room temperature?

    Asked by roirry to Steven on 14 Jun 2015.
    • Photo: Steven Thomson

      Steven Thomson answered on 14 Jun 2015:

      Great question!

      Quantum computers don’t actually have to be at room temperature. The real problem is that most of the ideas we have for making quantum computers work right now require really low temperatures, around -200C. If we get quantum computers to work at -200C that would still be amazing, but it wouldn’t be very practical, because liquid nitrogen coolant isn’t easy to come by. It’s dangerous, expensive, and if you let the computer heat up it would stop working and could take days to cool it back down again. Imagine restarting your computer and being told it would take a whole day!

      What would be great is if everyone could have a quantum computer in their home, or in their pocket, or on their wrists like a watch. As long as we need to keep them cooled with liquid nitrogen, quantum computers would have to stay in special facilities with a trained team of scientists making sure they stayed cold all the time. If we could make them work at room temperature without needing elaborate, dangerous coolant like liquid nitrogen, then everyone could have a quantum computer!