we all know that there is upper limit for speed that is speed of light, but is there a lower limit, I mean is there quanta for speed.
Thank you that helped.There is no quanta for speed.
The effective "lower limit" for speed will be the uncertainty principle, because of the wave-particle duality. The speed of a particle can be arbitrarily close to zero as long as the uncertainty in the position is sufficiently large (i.e. the particle is delocalized).
If a particle is confined to any discrete region of space, there will be a lower limit on its velocity. Hope this helps.