It's still a single flow of time right? So more like two time-scales than two time dimensions? e.g. day and night cycle plus monthly cycles happening together on the same time variable. Have I understood this all wrong?
That’s how I read it too. More that they’re encoding another aspect into their pulsing. But “multidimensional time atoms” is probably a much more appealing headline.
Yep, this is it. The key is not that there are two time dimensions but two independent time translation symmetries, each which translates the system by a different period of time corresponding to the two frequencies in their pulse. The two time dimensions is an analogy that’s useful for the theoretical treatment of such a system.
Fourier series is one way of separating out multiple time-scales, especially when they are regular and periodic. The example I gave will be amenable to that because the cycles are very periodic. But the different timescales don't have to be periodic. They can be quasi periodic, or completely irregular. They just have to run at different speeds.
That's what I said too. The article seems to describe scales rather than dimensions. They specifically say there's just one flow of time. But as one the comments below says, there are two time-translation symmetries. Which in certain contexts can be thought of as multiple scales. It is also very common in the real world