Am. Chervyakov et Vv. Nesterenko, IS IT POSSIBLE TO ASSIGN PHYSICAL MEANING TO HELD THEORY WITH HIGHER DERIVATIVES, Physical review. D. Particles and fields, 48(12), 1993, pp. 5811-5817
To overcome the difficulties with the energy indefiniteness in field t
heories with higher derivatives, we propose to use a mechanical analog
y-the Timoshenko theory of the transverse flexural vibrations of beams
or rods well known in mechanical engineering. This enables one to int
roduce the notion of ''mechanical'' energy in such field models that i
s wittingly positive definite. This approach can be applied at least t
o the higher derivative models which effectively describe the extended
localized solutions in the usual first order held theories (vortex so
lutions in Higgs models and so on). Any problems with negative norm gh
ost states and unitarity violation do not arise here.