Impact factors exist to quantify the "impact of a paper."
Does a similar metric exist for quantifying the pace of change (obviously determined by quantity of high-impact factor papers) in a particular field (physics, in particular)?
Although far from perfect, Citation half life is one citation-based indicator often used to quantify how quickly a field or journal is moving. It basically looks at how long a paper takes to get half of all its citations. So for example, a fast moving field might have a citation half-life of 4 years, whereas a slower moving field might have a citation half-life of over 10 years.
In the Journal Citation Reports you can see these values for each journal.
Of course, there is the question of what exactly this means. For example, I believe fields like statistics and mathematics have much longer citation half lives, perhaps because seminal articles remain important.
Understanding citation half-life is also important when you want to compare impact factors for journals across fields, or compare citation counts and h-indexes across scholars.
I don't think that is any meaningful metric.
Take medicine, for example. It is a very conservative, slow moving field, and yet, one of the fields that publishes the most. On the other end we have things like computer vision and machine learning research, that publish a relatively small share, but are advancing at an astonishing rate (for example, in deep learning, almost everything older than 5 years is completely outdated now).
If you want a more useful metric of pace of change one could look at the number of research level books relative to the normal volume of journal publications. Writing a book takes a long time, and only makes sense in fields that are going to remain stable for a few years; but I am not aware of anyone keeping track of this.
While not global and not generally used, if at all, the UK Research Excellence Framework (REF) divided research into 36 fields and assessed the "excellence" of "every" university in the UK. From this, the "research power" can be calculated. While there is no agreed upon standard, it is something like the ‘grade point average’ [GPA]) multiplied by the full-time equivalent (FTE) number of researchers submitted. While this is usually used to create league tables of departments or universities, there is no reason one could not create a league table of fields that ignores the university.
That said, it is important to note that most academics, I believe, would argue there is no reason to create such a meaningless number.