varies appreciably [adverb placement]

[yashar]

Hello

Please consider the below sentence.

If A ‎is ‎small relative to the time B‎, over which the density matrix of the system varies appreciably, then over a time duration of ‎B ‎the ‎correlation ‎functions ‎becomes ‎small ‎and ‎the ‎density ‎matrix ‎of ‎the ‎system ‎won't ‎change.

I want to know if the placement of the adverb appreciably is correct. I read somewhere that adverbs usually come before the main verb of the sentence. However, I saw in a scientific book that the adverb appreciably came after the main verb.
Are there other rules which tell us how to use adverbs in a sentence?

Thank You

 

[owlman5]

English permits considerable freedom in the placement of adverbs, yashar. Your placement of "appreciably" looks fine to me.

 

[jtm2292]

I think in scientific writing, in this particular case, the position of the adverb "appreciably" is best after "varies", which is what you wrote in your post. To me, it sounds slightly conversational to place the adverb before the word "varies". I think the usage is just stylistic however, and the meaning of the sentence isn't changed in any significant way. It just sounds more declarative (which scientific writing often strives for) versus conversational in my opinion. Also, placing it after puts emphasis on the adverb rather than the verb, which seems in this case to be more important.