Phonon

Here's the most extreme example of beat and no-beat I've found. Perhaps the ultimate example possible, I don't know. It's called a phonon, and it's a quantum of vibration, as a photon is a quantum of light.

“Qubit excited-state probability, Pe, as a function of interaction time, τ, and detuning, Δ, showing state transfer between the qubit and the resonator, in which a qubit excitation is exchanged with a phonon in the mechanical resonator (left, simulations; right, experiment). The red dash–dot line is at the resonator frequency, fr.” (701)
Aaron D. O’Connell et al., “Quantum Ground State and Single Phonon Control of a Mechanical Ground Resonator,” Nature 464 (March 17, 2010), 697–703 (701).

“Pulse sequence to generate coherent phonon states. With the qubit at its resting frequency, an on-resonance Gaussian pulse of fixed duration (5.0 ns) and variable amplitude is applied to the resonator. The qubit is then tuned to Δ = 0 and left for an interaction time τ; the qubit excited-state probability, Pe, is then evaluated. b, Measured Pe as a function of pulse amplitude and interaction time, τ.” (702)

What this means: When you pass one phonon into this chilled (nearly 0K) tiny tuning fork 30 microns long (slightly visible to the naked eye), it vibrates and does not vibrate simultaneously.

That's like having a Cantor set where the lines and the gaps are superimposed on each other. To achieve this magic you have to pass the phonon through a qubit. A qubit, unlike a classical switch, can be ON, OFF, or BOTH OFF AND ON.

Incidental stuff that makes me excited, maybe you can help. A quantum NOR gate would be what? Someone help me out here. A classical NOR gate corresponds to logical NOR: if both inputs are below a certain threshold (neither...nor) the gate is ON. Presumably you could build a quantum NOR gate in which the gate could be ON or OFF simultaneously as well as ON or OFF simply, based on the same input. Yes? Just wondering, crazy dark designs...