[net.physics] Does nonlinear mean non-local?

gjphw@iham1.UUCP (01/22/85)

   In these discussions concerning nonlinear phenomena, I have been
 puzzled by the association between nonlinear and non-local.  For
 example, it is my understanding that phenomena such as solitons, which
 are waves in nonlinear media, are quite localized.  Conversely, the
 spatial extent of a particle wavefunction, which leads to the Aspect
 experiment that refutes hidden variable theories, arises from a linear
 Schroedinger equation.

   In other words, it does not appear that nonlinear phenomena are
 necessarily non-local, and non-local phenomena are not necessary
 nonlinear in origin.  Or, have I missed this issue entirely?

   Another example of nonlinear phenomena occurs in systems with memory
 (which might be considered non-local in time).  This is better known
 as hysteresis (e.g., magnetization in iron).

-- 

                                    Patrick Wyant
                                    AT&T Bell Laboratories (Naperville, IL)
                                    *!iham1!gjphw