libs out there

Do you know or have done with physics research know any libs for dowbload, i don't know any physics research but will do some day.
later, i gess, please tell what you have used
thank you

Not sure if I totally understand what you're asking, but if you're looking for physics middleware/libraries then you could look at something like the Tokamak or NovodeX physics SDKs?

http://ode.org/