re:Flow of energy

["James W. Wheeler" <jwheeler@eagle.lhup.edu>]

Thank you.
question 1:  Can photons flow?  
question 2:  Can there be a flux of luminous energy?
question 3:  Is a particle a lump or a distribution or ...?
question 4:  Do particles flow?
question 5:  Can there be a flux of particles?
etc...
question inf:  Can energy flow?
question inf+1: Can there be a flux of energy?

On Thu, 4 Sep 1997, David Bowman wrote:

> James Wheeler asked:
>
> > What is a photon? What is an elementary particle?  What is mass?
>
> A photon is single-particle exitation of the Maxwell 4-potential field which
> itself is a real representation (i.e. its own uncharged antiparticle) of the
> adjoint representation of the U(1) gauge group which also forms a massless 
> spin-1 unitary representation of the Poincare' group.
>
> E. Wigner has defined an elementary particle as an irreducible continuous 
> unitary representation of the Poincare' group.
>
> Mass is the (Lorentz) invariant magnitude of the energy-momentum 4-vector
> (actually covariant 1-form) of some object.  This magnitude (when written in
> mass units) is the object's internal (or rest) energy divided by c^2.  The
> internal energy is the energy of the object when viewed from a frame for which
> the object's total momentum is zero.
>
> (These definitions ignore any subtleties that may occur in a general
> relativistic curved spacetime context.)
>
> David Bowman
> dbowman@gtc.georgetown.ky.us