Time is not an observable in standard quantum theory. In an operational setup, one can still use dynamical systems to measure time autonomously, so called clocks that generate information about the time passed. However, existing measures of clock accuracy do not capture the amount of information produced by a clock and some clock signals that require a lot of knowledge about time are assigned a low accuracy.
In this talk, I present a new measure of clock accuracy that captures the amount of information a collection of clocks generates. By identifying a set of “worst” clocks that mark the zero-point in time information, we can base this measure on a relative entropy between clock collections.
This new information-Content of clocks links nicely to exiting measures of accuracy. It gives rise to many interesting questions about the dynamics generating the signal and the nature of time itself.