A couple questions: is mass quantized? Energy is quantized, and momentum has eigenvalues for its operator so I took that to mean that momentum is also quantized. If those two are true (might not be! I'm new to this :tongue:), following E^2 = (pc)^2 + (mc^2)^2 Would that not mean that mass is also quantized? And the actual question I wanted to ask: Is there an operator associated with mass?