Why can't we define a time related operator?

[Demystifier]

I was under the impression that unparticles are still a speculative line of research. Is this no longer the case?

This requires a more extensive response/discussion, which might be off-topic (or at the wrong level) for this thread. Do you already have an old thread for these papers which could be reactivated, or should we start a new one?

Unparticles are indeed speculative, in the sense that there is no evidence that they exist in nature. But they are a consistent theoretical concept demonstrating that some features we are not used to are possible at least in principle.

Concerning the other topic, you may start a new thread and I will be happy to contribute to it.