Kinematic variables in noncommutative phase space and parameters of noncommutativity

Abstract

We consider a space with noncommutativity of coordinates and noncommutativity of momenta. It is shown that coordinates in noncommutative phase space depend on mass therefore they can not be considered as kinematic variables. Also, noncommutative momenta are not proportional to a mass as it has to be. We find conditions on the parameters of noncommutativity on which these problems are solved. It is important that on the same conditions the weak equivalence principle is not violated, the properties of kinetic energy are recovered, and the motion of the center-of-mass of composite system and relative motion are independent in noncommutative phase space.