  A photon-like wavepacket based on novel solutions of Maxwell's equations is
proposed. It is believed to be the first 'classical' model that contains so
many of the accepted quantum features. In this new work, novel solutions to
Maxwell's classical equations in dispersive guides are considered where local
helical twists with an arbitrary angular frequency W modulate a classical mode
(angular frequency w, group velocity vg). The modal field patterns are
unchanged, apart from the twist, provided that the helical velocity vh equals
vg. Pairs of resonating retarded and advanced waves with modal and helical
frequencies (w,W) and (w,-W)respectively, trap one temporal period of the
underlying classical mode forming a photon-like packet provided W = (M+1/2)w:
'Schrodinger' frequencies. This theory supports experimental evidence that the
photon velocity does not change with M in dispersive systems. Promotion and
demotion increase or decrease the helical frequencies in units of w. An energy
of interaction between retarded and advanced waves in the wave-packet is also
proportional to these helical frequencies W = (M+1/2)w similar to Planck's law.
Group velocity and polarisation are unaffected by the value of M. Advanced
waves enable phase and polarisation to be predicted along all future paths and
may help to explain the outcomes of experiments on delayed-choice interference
and entanglement, without causality being violated.
