The property producing a field has a qualitative and a quantitative aspect. The former may appear as1, 2, 3,..., n possibilities in the source particles. Interaction lines representing the field must reflect these possibilities. Thus, one expects there to be1, 2, 3,..., n respective kinds of lines joining particles. The different lines interact with each other as well as with the particles at their ends. For gravitational fields,n is1; for electromagnetic fields,n is2; for chromodynamic fieldsn is3. Rest mass can be (...) created by itself out of energy. But a positive-negative pair is the minimum possibility with electric charges, and a color-anticolor pair with quarks. A triplet of quarks or antiquarks, together with the appropriate neutrino, could also arise out of energy. (shrink)

A tachyon or a superluminal wave group appears as a spacelike structure through a region in the reference frame in which it is at rest. Such a structure can arise from residue left (a) by a particle or wave group traveling at fundamental speed c or less, or (b) in the creation or separation of particles. Thus, Maund's argument does not prove that tachyons cannot exist. Creation may include lepton-quark production as well as particle-antiparticle production.

In the approximation that every inertial observer experiences a homogeneous, uniform flow of time and sees a space that is Euclidean, the arena of physics is Minkowskian and one speed is the same in all intertial frames. If a given intertial observer finds an infinitesimal source or particle traveling faster than this fundamental speed near a given event, the source must appear in some inertial frame spread over neighboring positions at a given time as a spacelike structure. If this structure (...) persists over a period of proper time, it can be interpreted as a wave group. If it is conserved, it can be interpreted as a line or tube of force. (shrink)