I'll clarify that when he says sub-nanosecond timesteps, he means way sub-nanoscale timesteps. Femtosecond timesteps are used at the molecular dynamics level.

I'll clarify that when he says sub-nanosecond timesteps, he means way sub-nanoscale timesteps. Femtosecond timesteps are used at the molecular dynamics level. Even smaller ones are used at the QM level.