What do you mean by 'single qubit operation' within this context? Is there something significant about having a 'single qubit' with quantum coherence properties preserved rather than multiple qubits simultaneously? Doesn't each qubit require its own quantum logic gate? Therefore I would assume that success with multiple qubits is indicative of many single qubit operations being successful? I'm not trying to sound silly here, I genuinely just don't understand. Whenever I read about single qubit operations I've always just thought they were simplifying the description by focusing on one qubit rather than many. I assume that once you get the first one through the rest are pretty quick to follow?
An arbitrary single qubit gate is achieved by rotation in the Bloch sphere. The rotations between the different energy levels of a single qubit are induced by microwave pulses sent to an antenna or transmission line coupled to the qubit, with a frequency resonant with the energy separation between the levels. Individual qubits may be addressed by a dedicated transmission line, or by a shared one if the other qubits are off resonance. The axis of rotation is set by quadrature amplitude modulation of the microwave pulse, while the pulse length determines the angle of rotation.
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https://en.wikipedia.org/wiki/Superconducting_quantum_computing)
On a related note, Mohammad co-authored a paper (Room temperature manipulation of long lifetime spins in metallic-like carbon nanospheres) in 2016 that may be worth reading:
https://www.nature.com/articles/ncomms12232Maybe someone can explain all of this stuff in layman's terms. Sometimes I read paragraphs of this stuff and I think "that makes sense" but if I was asked to explain it I'd feel a bit like Homer Simpson.
(20min delay)