Extremely rapid; so rapid that it may include to occur in femtoseconds or in a attosecond.(adjective)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "ultrarapid" in a sentence
"Five of the six guests were convinced that dramatic advances in a number of areas, including chemistry, optics, and computing, would be harnessed into an affordable bench-top instrument for ultrarapid DNA sequencing in the near future."
"The solution thus is that codeine is bioactivated by CYP2D6 into morphine, certain patients show an ultrarapid form of this metabolism, which leads to a life-threatening intoxication see Gasche et al."
"Looking further ahead one can see, for example, the possibility of building ultrarapid trains that run on superconducting tracks."